View Full Version : Question on possible causes for overheating
Took the car and drove to Alice's this morning. Was by far the longest trip I've taken and was a good test of my transmission fix a couple of months ago. Anyhow, the car ran really well, except when we were in town stuck in traffic on the way there, and also on the way back home. On the way there when crawling in signal-to-signal traffic the temp went up to around 220 at which point I turned the aux fan switch on, and the temp stabilized until we got on the freeway where it came back down to 180. On the way back, when it was warmer, we got stuck in the same in town traffic and it got kind of stressful. In the center lane with nowhere to go we got stuck at some lights, and the temp started climbing again. Turned the fan switch on, but this time it was no help. Temp got up to above 240 and I really started to freak out. Once out of that traffic the temp dropped back down to normal. Just trying to draw on the collective knowledge base to see what I should be checking. I was going to try re-burping the cooling system to see if it has developed a bubble and check the fuse for the aux fan switch. Not sure how I could check that the fan is turning on automatically when the temp starts up. Other than those I'm kind of at the limit of my personal knowledge base, so any other ideas would be appreciated. I'm running the radiator that FFR offered when I bought the kit back in 2012. Thanks
Jeff Kleiner
05-13-2023, 05:58 PM
Do you have a shroud on it? If not when you aren’t moving you’re only drawing air across the radiator in the circular area that the fan covers. With a shroud sir is pulled across the entire radiator surface.
Jeff
Rdone585
05-13-2023, 06:05 PM
One of the first things is to make sure there is no air in the coolant system. After that ride, and after it cooled down a little, did you check the coolant level? Was it low? If so, you may need to keep working on getting the air out. The next thing to look at is the fan, is it pulling air through the radiator, I suspect it is, but check anyway. As you found, the easiest way to tell if the fan turns on automatically (by thermostat control), is to let it idle in your driveway until the fan turns on. When it does, look at the temperature. The next topic is to make sure your fan is pulling the most it can through your radiator. Did you install a shroud? If not, you could be loosing cooling efficiency because less than optimal air is being pulled. Without a shroud, the air is pulled primarily in front of the fan wings. With a shroud, the air is pulled across the entire radiator surface, thus utilizing the maximum cooling capacity of the radiator.
Hope this help to start your journey towards a cooler ride...
Jeff, I have a Breeze shroud and the piece at the top of the radiator that stops air from going over the top plus I made panels that mount on the frame in front of the F panels that help to stop air from going around the sides. I got the design from Chris, can't remember his screen name. He did his own bodywork a number of years ago and did some really involved threads showing how he did things.
Rdone, I've got the funnel that goes into the highest fill point in the cooling system. You fill it with coolant and run it up to temp. You can tell when the thermostat opens, and I thought I had it fully burped, but maybe not. When I redo this, I'll monitor when the fan starts based on temperature.
Thanks guys for the ideas.
egchewy79
05-13-2023, 07:56 PM
Make sure the fans pulling air as well and not pushing it. Very easy to switch the polarity of the wires.
MB750
05-13-2023, 08:53 PM
Have you subjected the car to very similar conditions in the past and had no issues?
You mention transmission repairs, what were they?
Did you do anything else during the transmission repairs? Anywhere else on the car?
Norm B
05-13-2023, 11:41 PM
Some other items you might want to check. Have a good look at the front of the rad. Make sure there are no obstructions. Check the belt tension. Did you try revving the engine to see if that dropped the temp? Under drive pulleys might not allow the pump to move enough coolant at idle.
Good luck
Norm
Kbl7td
05-14-2023, 04:37 AM
Better fan
https://www.summitracing.com/parts/flx-105390?srsltid=AR57-fAJLTCqL8dBByYCQXV9URc4U6oNE4E7P4YulYwbwuymKGlbVYk bvQM
CraigS
05-14-2023, 07:31 AM
Your fan not coming on itself is a major problem. W/ a 180deg normal temp the fan should come on at about 195. I'd look at the control circuit and especially the temp sensor. In general it should be wired like this.
184494
Some relays will have the power in combined into one pin so 30 is connected internally to 86 and there is no pin 86 that you can see. It is very possible that your second overheat was not really a separate problem. I noticed on mine that, if I let the temp go up til the fan kicked on automatically, it took a long, long time to bring the temp back down when still in traffic. So usually I hit the manual switch when I first slowed or when the fan kicked on by itself. This way the temp would stay at 180 no matter what. BTW you can check this easily in the garage. Start it up and let it idle while watching the temp. Right after you fire it hit the manual switch. The fan should come on no matter the temp. Then let it warm up (fan sw off) to see if it comes on by 200. If not check the electrical circuit. BTW you haven't described your cooling system. I mention that because I never burp the system. I remove the sensor or plug in the intake (mine was just behind the t-stat housing) so air can come out. I fill at the t-filler until liquid comes out that hole and then screw the sensor or plug back in. Usually I can only get a couple more ounces into the t-filler and then I install the pressure cap. I never take the cap off again. All top up coolant goes into the reservoir. Then I fill the reservoir 50% and fire up the engine. I let it warm until the t-stat opens (feel the top rad hose get warm) then shut it off. I watch as it cools to be sure the reservoir never goes dry as coolant is sucked back into the engine. I usually need to add some coolant the first 2 cycles. I go through this warm/cool cycle 3-4 times, the last cycles being short drives around the block. I look for the reservoir (1.5 qt minumum size) to be 1/4 to 1/3 full cold and 2/3 to 3/4 full warm.
Lickity-Split
05-14-2023, 07:40 AM
I had a similar heating situation with my MK4 roadster.
First, contrary to logic, I removed the piece along the top of the radiator thus allowing more air to flow over the radiator into the engine compartment.
Second, I installed a Flex A Lite 3,000 cfm fan like the one mentioned above.
Note: good working coolant recovery tank, and no air in system.
Problem solved for me.
Bob Cowan
05-14-2023, 08:18 AM
Too much base timing or a lean mixture at idle will cause these problems as well.
weendoggy
05-14-2023, 10:18 AM
1) shroud
2) 2600CFM or lager fan...PULLER
3) 185-190° fan thermostat switch, best plumbed in radiator engine inlet side, also intake flow (I have both)
4) what's controlling the "auto" fan response now? Where's the sender?
5) engine thermostat?
6) correct rotation water pump?
I run a SBF347 w/HP, 2600CFM 16" Spal puller and redundant fan control. I was in the same BA traffic yesterday and could barely get mine to 190° and fan did it's job. Also, 3 row non-aluminum radiator to boot. Something is a miss. jmo
WOW! I had hoped to get a couple of responses when I posted, but holy crap! I've got my dance card filled for this week to check all these things out. I'm going to start with those items that require inspection or adjustment and move from there into items that may require replacement. As I, and many others, have said before, this forum is amazing. Thanks for all the input guys. I'll report back once I get the chance to check these things out.
Railroad
05-14-2023, 02:02 PM
At the end of the day, add a bottle of Water Wetter. I know, I know.
He is not moving enough air across the rad with the fan alone......
mrmustang
05-14-2023, 02:29 PM
Took the car and drove to Alice's this morning. Was by far the longest trip I've taken and was a good test of my transmission fix a couple of months ago. Anyhow, the car ran really well, except when we were in town stuck in traffic on the way there, and also on the way back home. On the way there when crawling in signal-to-signal traffic the temp went up to around 220 at which point I turned the aux fan switch on, and the temp stabilized until we got on the freeway where it came back down to 180. On the way back, when it was warmer, we got stuck in the same in town traffic and it got kind of stressful. In the center lane with nowhere to go we got stuck at some lights, and the temp started climbing again. Turned the fan switch on, but this time it was no help. Temp got up to above 240 and I really started to freak out. Once out of that traffic the temp dropped back down to normal. Just trying to draw on the collective knowledge base to see what I should be checking. I was going to try re-burping the cooling system to see if it has developed a bubble and check the fuse for the aux fan switch. Not sure how I could check that the fan is turning on automatically when the temp starts up. Other than those I'm kind of at the limit of my personal knowledge base, so any other ideas would be appreciated. I'm running the radiator that FFR offered when I bought the kit back in 2012. Thanks
What compression is your motor?
What cam do you have installed?
What is your timing at idle?
What thermostat is installed?
Who's water pump is installed, and did you check to see if the vanes are in the correct orientation for your belt set up and it's rotation?
Is there a small 1/8" hole drilled at the 12 O'clock position before it was installed?
Who's radiator is installed?
Which fan is installed?
Bill S.
You have 8 stack EFI, right? Do you not have the ecu controlling the fan? If not I would hook it up that way. It gives you much better fan control.
Hoooper
05-15-2023, 11:11 AM
Im going with a tune issue. The standard fan with a shroud pulls plenty of air to keep even a really wild 331 cool in traffic.
Avalanche325
05-16-2023, 03:01 PM
The only things I can think of that are not mentioned.
You do have a thermostat installed? Not having one moves the coolant through the radiator too fast.
You are not running 100% antifreeze? Not counting the ready to go pre mix.
gbranham
05-17-2023, 09:25 AM
I was thinking incorrect rotation waterpump.
Also, on my first build, I had some overheating issues, and to ensure I knew my fan was kicking on automatically, I wired up a small light on the dash to illuminate when the fan was on. Sometimes, it's hard to hear it. My overheating issues were related to air in the coolant system. Jacking up the front of the car helps when you're burping the system. Milk that lower radiator hose. I'm sure you've read all about burping the system. Good luck...you'll find the culprit!
Going to get into this today. Haven't had any time to get started until now. There have been more than one mention of a water pump with the wrong rotation. Since I did not assemble this engine, and have no way of knowing what was used, is there any way to determine which direction a specific water pump should be rotating short of removing it to check the vanes internally? I'm guessing that this is not the issue, but it would be good to know. Actually, my money is on the fan not coming on either through the fi ecu or the aux switch. When moving along in traffic the temp stayed at 180, but as soon as I was slowed or stopped in traffic the temp would start to climb. I guess I'll find out.
Jeff Kleiner
05-17-2023, 11:11 AM
... There have been more than one mention of a water pump with the wrong rotation. Since I did not assemble this engine, and have no way of knowing what was used, is there any way to determine which direction a specific water pump should be rotating short of removing it to check the vanes internally?
Yes! The bolt circle is different for standard (clockwise when viewed from the front)pumps vs reverse rotation pumps (counterclockwise when viewed from the front). Standard rotation bolt circle is 1.75", reverse rotation bolt circle is 2.0625".
Jeff
Avalanche325
05-17-2023, 03:47 PM
...... bolt circle is 2.0625".
Jeff
Can you be more specific please?
I've been out in the garage trying to determine the same thing. Not sure where that 2.0625" measurement is taken on the water pump.
At least I did determine the biggest problem that I have, and that's the fan not coming on, either with the aux switch on the dash, or from the ecu of the efi system. The cooling fan fuse, 30 amp, is fine so it has to be somewhere else. I'm waiting for things to cool down a bit before I start my search. You notice how I say that like I'll know what to look for: confused:
David Williamson
05-17-2023, 05:17 PM
start with the simple stuff, look at the wire connectors like the fan to the wiring harness. i had one of them come loose on my Coupe. You can also test the fan by jumping 12 vots from the battery.
David W
That's the plan David. I just hate electrical issues. The electrical is one of the things that although I managed to get through it, I still don't completely understand it.
Jeff Kleiner
05-17-2023, 06:35 PM
Can you be more specific please?
I've been out in the garage trying to determine the same thing. Not sure where that 2.0625" measurement is taken on the water pump.
There are 4 bolts on the water pump pulley. Measure from the center of one to the center of the one 180 degrees opposite it…you’ll find it is either 1.75” or 2.0625”
Easy peasy…that’s the bolt circle!
Jeff
Thanks Jeff! I think I could have tried figuring that out for who knows how long, and still wouldn't have figured it out!
I checked the connection to the fan motor, and nothing appears to have been loose. If I remember correctly, those were some of the hardest connectors to put together. I've got to get a 12v source to try jumping the fan just to make sure it's not the problem. Other than that, I don't know where to go from there. Everything else is pretty much buried under the dash. I suppose I'll try starting it up again and hook up the efi monitor and check the setup on the fan operation. At that point I'm hosed.
D Stand
05-17-2023, 11:41 PM
There is a relay for the fan as well. It should be the one right next to the fuse. Swap in a new one to see if it might be your problem as well.
Norm B
05-17-2023, 11:50 PM
Don’t assume the fan is bad if jumping a 12 volt lead directly to the positive side of the fan circuit doesn’t cause the fan to run, you could have a bad ground.
Check for voltage at the fan connection with your dash switch on. If no voltage then replace your fuse even if it looks good.
The last item up for bid is, the fan relay. Both the ECU and the dash switch provide the ground part of the trigger circuit and they are separate so, it is unlikely a ground issue. That leaves the positive side of the trigger circuit and the supply and output leads or the relay itself as the issue.
Good luck
Norm
CraigS
05-18-2023, 06:36 AM
Don’t assume the fan is bad if jumping a 12 volt lead directly to the positive side of the fan circuit doesn’t cause the fan to run, you could have a bad ground.
Check for voltage at the fan connection with your dash switch on. If no voltage then replace your fuse even if it looks good.
The last item up for bid is, the fan relay. Both the ECU and the dash switch provide the ground part of the trigger circuit and they are separate so, it is unlikely a ground issue. That leaves the positive side of the trigger circuit and the supply and output leads or the relay itself as the issue.
Good luck
Norm
Good call Norm. The fan is (or should be) controlled by the ground side of the circuit. You can run power to the fan all day long and nothing will happen if the grounds are not there.
Jeff Kleiner
05-18-2023, 06:54 AM
Good call Norm. The fan is (or should be) controlled by the ground side of the circuit. You can run power to the fan all day long and nothing will happen if the grounds are not there.
Precisely!
Jeff
D Stand
05-18-2023, 09:33 AM
Good call Norm. The fan is (or should be) controlled by the ground side of the circuit. You can run power to the fan all day long and nothing will happen if the grounds are not there.184657
Not true. The fan itself has a ground to it all the time. The ground trigger from the ECU or dash switch is triggering the negative side of the cooling fan relay coil. This relay then switches a positive trigger to control the fan. So, confirm you have a good ground at the fan, then you can jump off the battery to confirm you have a working fan versus a control issue.
J R Jones
05-18-2023, 11:43 AM
One could relay the fan ground and it would be creative. That would put the "live" wires at more risk of a ground fault.
If indeed neither the thermostat or the switch turn on the fan, I too would suspect the relay or associated conductors.
jim
Why did it have to be electrical? The fact that the fan was working correctly when I first set it up with both the aux switch and the ecu is frustrating. I'm just no good at diagnosing electrical problems mostly because I understand the basic premise of how the circuits work, but I'm not knowledgeable enough to know how to proceed.
I guess today I'll check continuity in the wires feeding the fan to see if there is a break somewhere. If I disconnect the leads from the fan and connect my multimeter to those leads, and I start the car and turn on the aux switch should I get a reading of voltage? Same thing in letting it heat up to the point where the ecu should trigger the fan? If I'm not getting a voltage reading for either of these would that point to a bad relay or ???
phileas_fogg
05-18-2023, 02:16 PM
Keep at it Rick, even if you have to step away for a while. You've got lots of help, and a solid plan. You'll track this gremlin down & fix it soon enough.
John
D Stand
05-18-2023, 03:03 PM
Why did it have to be electrical? The fact that the fan was working correctly when I first set it up with both the aux switch and the ecu is frustrating. I'm just no good at diagnosing electrical problems mostly because I understand the basic premise of how the circuits work, but I'm not knowledgeable enough to know how to proceed.
I guess today I'll check continuity in the wires feeding the fan to see if there is a break somewhere. If I disconnect the leads from the fan and connect my multimeter to those leads, and I start the car and turn on the aux switch should I get a reading of voltage? Same thing in letting it heat up to the point where the ecu should trigger the fan? If I'm not getting a voltage reading for either of these would that point to a bad relay or ???
That’s a good start. If no voltage it will be fuse, relay, or connections. To confirm a good ground at the fan, take your multimeter set to ohms and go from battery negative or bare metal on engine with one lead and the negative wire at the fan. You should have continuity there. If not a good ground there, none of the other tests will help. Once you remove the leads from the fan, you can jump them right from the battery for a brief moment to see if the fan is simply working, fans can fail. If you need more help send me a PM and we can discuss more.
Thanks Dale
MB750
05-18-2023, 03:11 PM
I'm still curious if this issue has happened before. You've had the kit for over 10 years. Is this just now coming to light?
Thanks John.
Dale, really appreciate the offer. I'll see if I can make sense of what I'm doing with the testing and post some results. The fuse is intact, so it must be something else
MB750, I know it seems like a long time, but I didn't have it on the road until 2021, and then it languished at the painter's shop for about 14 months until I got it back last Sept. Then I discovered that I did not have 5th gear, so there was that repair that took way longer than expected. So, my drive to Alice's was the first long trip I've taken in the car. Everything else was just a few miles to C&C and not much else. It never manifested itself because I was never stuck in traffic or sitting at an idle for any length of time. I know that both the ecu and aux switch worked back when I had my first start and burped the cooling system. I have no idea when everything went bad. It has definitely not been one of the shorter builds!
Right now I'm just bummed because I'm signed up for the car show at the Cobra Experience Museum on 6/3. I was signed up last year thinking I'd have my car back from paint, but that didn't work out. I'll be PO'd if I miss it because of this.
MB750
05-18-2023, 07:41 PM
Ok, that makes sense then, thanks for confirming.
Rest assured, with all the brainpower in this forum, we'll help you resolve it.
No worries! That's exactly what I was hopeing for. Without the forum, and some local guys with more knowledge than me that were willing to step up, the car would still be boxes of parts in my garage, or someone else would own it.
Tested the ground, and it appears to be solid. Got continuity when going from the ground wire at the fan to a solid point on the frame. Also tested the fan motor to check for operation. Connected to power for just a second to get the fan to run, and it runs strong with no issues. Not exactly certain how to remove or test the relay. If the relay just pulls out of the fuse panel, is there a specific one that would need to replace it? After that it would have to be a break in the green fan thermo switch wire, or ???
J R Jones
05-19-2023, 09:32 PM
EZ$ Hold your fingers on the relay and turn the fan swtich on and off. You should feel the relay click.
If it does click at least the switch circuit is OK.
If it does not click, the relay coil may be bad or the switch circuit is bad.
Bosch relays have a schematic on top indicating the terminal function. If you pull the relay you can test the coil function with 12V and ground. Click means the relay coil is OK.
The contacts will be NO (normally open) and NC normally closed. With an ohm meter you can monitor if they function as you click the coil on and off.
jim
Rick,
The relays in the RF fuse panel are the same for the fuel pump, fan, and the horn. Try swapping them and see if the horn works with the swapped relay. Bosch relays come in a couple of typical configurations (4-pin and 5-pin). The relays in the panel are likely 4-pin (never looked at mine to see). They just pull out of the socket and can only be put in one way, so no worries about making a mistake. I didn't read all the posts, but what are you using to control the fan? You mentioned an auxiliary fan. Do you have two or did you wire in a separate switch from what is being used to automatically turn the fan on/off?
Dave
Edit: I read through the rest and see you have an EFI controlling the fan as well as a separate switch, but that neither are working. I also see that you can power the fan directly, so that is pointing to an issue with the relay or wiring to/from the relay. I assume you are using the Ron Francis harness, so you should have two green fan thermal-control wires; one in the sender bundle that will be at the top of the engine, and a second with the fan power & ground wires in the front harness. Either of these will close the fan circuit when grounded and with the key in the run position, should turn the fan on. For the EFI, be sure that the fan control is properly configured and that the temp is set a bit above the T-Stat temp. I have mine set to come on at 190 degrees with a 180 degree T-Stat. What ECU are you using with the stacks?
JR, I'll have to check this out.
Dave, quite a while ago you helped walk me through the setup of a manual switch along with the ecu. It worked when it was first set up. I'm using the FAST2.0. I'll have to check what temps I set the ecu on and off. I seem to remember on at 200 off at 190. I believe it's a 185 thermostat, but I have to hook up the screen to the ecu and go back through the readings.. I'll try pulling the horn relay and the fan relay and swapping them to see if that gets the fan going, and see if the horn still works.
Thanks guys. This gives me a couple more things to check out tomorrow. Hopefully this will get me to the bottom of this.
OK, so I followed Papa's suggestion that I swap the horn and the fan relays to see if that would expose a bad relay. The horn worked before the swap. After the swap it did not. I'm going back out to put the relay that is still good in the fan position and give that a try. Either way I apparently have a bad relay. Prices for an exact replacement are all over the map from around $5 to $15, and on some of the electronics sites they have a note that this part is not recommended for automotive use! The part is also being discontinued by Tyco Electronics so I'm sure that's why the price is such a spread. If I was to buy a replacement is the AMP rating the number that I should be most concerned with?
Rick,
Any 30/40 Amp single-pole, single-throw (SPST) normally open relay with the same pin configuration will work. Your local auto parts store will have them.
Dave
So the mystery revealed itself. When I first switched the relays nothing worked, not the fan or the horn. Then I tested the relay using the horn and got it to work with one of the relays, the one that was originally in the horn position. It was confusing why the fan didn't work with the good relay in place until I remembered that I had disconnected the fan to test it yesterday, and forgot to reconnect it! Reconnected, put the relay in the fan position, and voila! it worked. The aux switch turned the fan on, and then after turning that off and letting the motor heat up, the ecu turned the fan on at around 190, and it brought the temp down to 180 in just a few seconds.
Huge shout out to Papa for giving me the heads up on the fact that both the fan and horn relays were the same and to swap them to test to see if one was bad! I had pretty much reached the limit of my electrical troubleshooting capabilities, so I was stuck. I also want to thank everyone who responded to my original post with ideas on things to check out. This is where this forum really shines when so many people jump in to help a dumb a** like me get through this.
I also bought a new overflow tank for the radiator. It's a 2 liter with a sight glass on one side with the hose connections on the other. It also has a magnetized drain plug. I've been using the small unit that FFR provides with the kit, or at least what they provided back in 2012, and I'm not sure it has ever worked as intended. The only question or concern I have with the new unit is that the hose connections are both at the top of the side of the tank with no hose going down to the bottom of the inside of the tank. How would the cooling system draw any overflow back into the system without drawing from the bottom of the tank, or am I not thinking about this correctly?
Just now saw Papa's post about what type of relay, answering my earlier question, so now I won't have to drive around without a horn, because of course you need to sound the horn when you drive because the car is hardly ever noticed! Thanks Dave!
egchewy79
05-20-2023, 03:51 PM
Do you have a pic of the overflow tank? And why does it need a magnetic plug? I bought one off Amazon and the clear fluid sight tube leaked immediately. I found a large bolt to plug off these threaded holes and removed the sight tube
Not sure why it has that drain plug. I'll try to attach the ad on amazon. https://www.amazon.com/Radiator-Universal-Reservoir-Expansion-Automotive/dp/B0BKVKGHR3/ref=sr_1_13?adgrpid=1338106214573431&hvadid=83631877612654&hvbmt=bp&hvdev=c&hvlocphy=43949&hvnetw=o&hvqmt=p&hvtargid=kwd-83631979646522%3Aloc-190&hydadcr=5737_13190794&keywords=overflow+reservoir+tank&qid=1684282069&sr=8-13
Hopefully that worked. I was going to test it out before installing to make sure there were no leaks. I figured I could put some pressure in after putting liquid in and sealing it to test it. Still not sure how it could draw coolant back into the cooling system if both the hose fittings are well above where the coolant level would be.
It's not exactly the one I bought. I thought I had saved the amazon location in my favorites, but this one is identical to the one I bought just $7 more expensive. They are obviously made by the same company and just rebranded.
Rick,
On the overflow tank, I'd recommend using the bottom opening as the inlet and one of the top openings as the overflow. Cap the remaining top opening.
Dave
Thanks Dave. I think the threads on both of those openings are the same so I can just take the drain plug and swap it out.
OSU Cowboy
05-22-2023, 12:43 PM
I've had chronic high temp problems with my MK3.1. The last straw was a couple weeks back at a cars & coffee event where I get into this jammed parking lot with no place to go, lot's of cars stacked up and pedestrians around. I'm sitting with the car running of course and the temp just creeps higher and higher. I finally get out of there and back on the road and the temps come back down where they should be.
My set up, Breeze radiator mount, shroud, the top piece that covers the top of the cowl, and the thermocouple unit that should cycle the fan on.
I start wondering if my radiator fan ever comes on at all.
So - I cut the thermocouple out of the circuit, and go with a manual fan toggle on the dash which was already in place, but never worked with the thermocouple in the circuit. Verified fan comes on with the manual switch.
Then I go out for a test. Fan off, running on the highway, temps are great. Get into stop and go traffic, I let it heat up to 180 and then cycled on the switch. Now I know the fan is running ... and it absolutely did it's job, taking the temps back down to where it runs on the highway which is ~165 or so.
For me - problem solved. I don't mind the manual switch at all. I keep close watch on gauges all the time so it's not a problem in that respect. And, I know it's OK running with flow through the radiator. All in all, happy with the outcome. Sad it took me so long to sort it all out. The good news is ... I've now got both open road capability as well as parade capability - certainly didn't have that before.
Caddy Dad
05-22-2023, 02:52 PM
I have the same engine from Blue Print. All was good and then one day, my engine started overheating when stuck in traffic. When driving at 30+, there's enough airflow to keep it cool. My problem turned out to be a bad fan relay. The horn and fan use the same style relay. If your horn works, swap the the horn relay with the fan relay. If the problem moved to the horn, then you've isolated your problem. The relays are right next to each other on the fuse panel and easy to get to.
Hope this helps!
That was what happened to me. Got two new relays ordered so I'll have a spare just in case.
egchewy79
05-22-2023, 06:55 PM
Not sure why it has that drain plug. I'll try to attach the ad on amazon. https://www.amazon.com/Radiator-Universal-Reservoir-Expansion-Automotive/dp/B0BKVKGHR3/ref=sr_1_13?adgrpid=1338106214573431&hvadid=83631877612654&hvbmt=bp&hvdev=c&hvlocphy=43949&hvnetw=o&hvqmt=p&hvtargid=kwd-83631979646522%3Aloc-190&hydadcr=5737_13190794&keywords=overflow+reservoir+tank&qid=1684282069&sr=8-13
Hopefully that worked. I was going to test it out before installing to make sure there were no leaks. I figured I could put some pressure in after putting liquid in and sealing it to test it. Still not sure how it could draw coolant back into the cooling system if both the hose fittings are well above where the coolant level would be.
It's not exactly the one I bought. I thought I had saved the amazon location in my favorites, but this one is identical to the one I bought just $7 more expensive. They are obviously made by the same company and just rebranded.
Take one of the threaded barbs and put it at the bottom. This will connect to your filler T piece. Use one top hole for overflow and plug the rest. Again, don’t be surprised when the clear tube starts leaking. I used a very large metric bolt cut off to plug it.
Jaguar Engineer
05-22-2023, 08:06 PM
The only things I can think of that are not mentioned.
You do have a thermostat installed? Not having one moves the coolant through the radiator too fast.
You are not running 100% antifreeze? Not counting the ready to go pre mix.
This is a myth. Water running through the radiator “too fast” can’t cause overheating. It can cause erosion of the metal, but that unlikely based on just having a missing thermostat. The primary downside to not having a thermostat is overcooling, which has other performance implications.
egchewy, ii ended up returning that one today. It turned out to be too large to fit the available area. I ordered a different one yesterday, and it just arrived today. No site tube, and although this one fits the area it's actually bigger than the one I returned, 2.5 liters. I'm going to try to get it installed tomorrow and burp the system.
Well, I think I finally finished correcting the overheating issues that I had been experiencing. As you know it turned out to be the fan relay, but I was also concerned about the size of the stock FFR overflow tank. It only measured about 18 oz., and I was concerned that was not enough capacity, so I ordered a new tank.
https://live.staticflickr.com/65535/52923242349_e5e9ab65d6_z.jpg (https://www.flickr.com/gp/156322842@N02/6nk6CPn231)20230524_133833 (https://www.flickr.com/gp/156322842@N02/6nk6CPn231) by Rick Paul (https://www.flickr.com/photos/156322842@N02/), on Flickr
It's a 2.5 liter tank. It doesn't have the site glass, but I can deal with that. It was a snug fit with clearances about as small as I was comfortable with. It seems like anything that you try to add to these cars is a challenge to find a location where they will fit.
As I mentioned in my door card thread, I hope this is the last project for a while on the car. I'd actually like to get to drive it!