2.5 L Non turbo engine overheating

[Triathletedave]

I've been through several threads and have tried numerous solutions, but my engine is still overheating badly. There doesn't seem to be any circulation through the radiator. I am using the 2.5 L non turbo engine, and I installed the breeze coolant lines. There are no leaks in the system, but the engine outlet line is hot and the engine inlet line remains stone cold.

Here's what I've tried so far:

1. Lift the front end and slowly burp the system to try to remove air pockets.
2. Lift the rear and repeat the process above. I have a fill /flush port in the rear line that fed the old heater core.
3. Force flush coolant through the line with the rear end raised. That should have cleared any air pockets.
4. Replaced the thermostat. Turns out both the old and new thermostats work fine in a boiling pot test.
5. Completely replaced the radiator as there could have been some blockage inside the old rad.

Does anyone have any other tricks or tests that we could try out? As I don't have a turbo overflow coolant tank, most of the posted solutions won't work for me.

Thanks in advance.

Dave

[C.Plavan]

I would try filling it with this from the radiator since you do not have the turbo overflow tank. This is one awesome tool. Fully drain the system before use for the best results.

http://www.amazon.com/UView-550000-A...ywords=airlift

[wallace18]

Did you do the VCP coolant bypass trick to the engine top hose outlet? Air can get trapped without that mod.

[Triathletedave]

Did you do the VCP coolant bypass trick to the engine top hose outlet? Air can get trapped without that mod.

No, I did not try that. do I have to remove and drill out a hole in the top hose outlet to put in a bypass or bleed line? I don't have a degas tank either, so where would I run the line to?

[Bob_n_Cincy]

No, I did not try that. do I have to remove and drill out a hole in the top hose outlet to put in a bypass or bleed line? I don't have a degas tank either, so where would I run the line to?

Dave
In any cooling system it is important that the pressure release cap is at the highest point in the cooling system.
I would add an inline cap right after the engine outlet tube. Don't go down with the hose until after the this cap.
Overflow tank should be in the back of the car only.

Change the front radiator cap to a sealed cap. This cap will only be used to fill the system.

I personally would add a degas tank under the right hump.
Bob

[Triathletedave]

Z

Dave
In any cooling system it is important that the pressure release cap is at the highest point in the cooling system.
I would add an inline cap right after the engine outlet tube. Don't go down with the hose until after the this cap.
Overflow tank should be in the back of the car only.

Change the front radiator cap to a sealed cap. This cap will only be used to fill the system.

I personally would add a degas tank under the right hump.
Bob

Thanks for the advice Bob. It sounds like I have a lot of work ahead to get this issue sorted. Is there a cheap aftermarket degas tank that builders have used? I will start sourcing the parts I need right away.

[Bob_n_Cincy]

Z

Thanks for the advice Bob. It sounds like I have a lot of work ahead to get this issue sorted. Is there a cheap aftermarket degas tank that builders have used? I will start sourcing the parts I need right away.

I would use something like this.

http://www.summitracing.com/parts/ctr-80-200

This is the description:
These Canton Racing coolant expansion fill tanks are built with .100 in. thick aluminum. They have billet aluminum necks with a barbed overflow fitting and accept standard radiator caps. Expansion tanks provide an air space for the coolant to expand into and are required in all applications where the top of the radiator is lower than the top of the engine. These Canton Racing coolant expansion fill tanks should be mounted higher than the engine and radiator to ensure that the engine and radiator are completely filled. The tank itself should only be partially filled to allow for expansion. They have built-in mounting brackets, and an overflow hose can be connected to the filler neck barbed fitting.

I would change the fittings to fit your 1.5" radiator hoses.
from engine on top left. bottom to radiator.

Dave
If you have an 1/4" air bleed hose on you radiator, I would run the back to the expansion (degas) tank also.
Bob

[STiPWRD]

I would try filling it with this from the radiator since you do not have the turbo overflow tank. This is one awesome tool. Fully drain the system before use for the best results.

http://www.amazon.com/UView-550000-A...ywords=airlift

100% this tool works. Metros let me borrow his and I used it to remove all of the air from the coolant system in minutes. I've ran the car for 30 minutes and driven it with no overheating.

As Bob mentioned, it is also important to have the radiator vent cap at the highest point in the coolant system and to have liquid coolant in the overflow tank that receives the hose from the vent cap.

[Buzz Skyline]

If you pop off the heater core bypass hose (the little u-shaped section of hose FFR provided), you can check to see if it's wet. If not, you aren't getting any flow past the thermostat when the engine is warming up and your thermostat will fail to open even with the engine hot. You can also fill it with coolant from there, just in case. You should still add coolant the other ways, but there seems to be a place at the back of the engine that traps air, I think.

In any case, it's a quick and easy thing to check.

[Triathletedave]

Thanks for all of the feedback. Since I'm new to this, I do not know the difference between a degas tank and an overflow tank. Is there a simple explanation of the difference? Which do I need for my application?

Cheers,

Dave

[Bob_n_Cincy]

Thanks for all of the feedback. Since I'm new to this, I do not know the difference between a degas tank and an overflow tank. Is there a simple explanation of the difference? Which do I need for my application?

Cheers,

Dave

Dave,
A Degas tank, fill tank, and expansion tank are usually names used interchangably.
It is a PRESSURIZED tank with a radiator cap on top.
A degas or fill tank are full if operating correctly. A expansion tank is usually only kept 1/2 full allowing room for expansion.
EDIT: In a normal car, the top of the radiator performs this function. Since the top of the radiator is not at the highest point of the cooling system on and 818, this tank is needed.


A overflow tank is NON Pressurized that hold liquid that has come out of the radiator cap pressure relief valve.
The small hose from the radiator cap goes to the bottom of the overflow tank. When your engine cools, the fluid gets sucked back into the radiator or one of the tanks above. Normally this tank is about 1/2 full.

You need both

Bob

[STiPWRD]

A degas tank is a location at the top of your coolant system (which is pressurized) where water vapor collects and is vented through a spring loaded cap. This is what it looks like:
degas tank.jpg
The water vapor is vented through a hose into the overflow tank where it condenses back to liquid and equalizes the pressure inside the degas tank. When the car cools down, this liquid coolant gets sucked back into the degas tank to equalize the pressure back at the colder temperature. The overflow tank is not pressurized and can be virtually any container, even a water bottle if it won't melt. But there needs to be a liquid water barrier between the hose from the degas tank to the overflow tank, so in the stock system the end of the hose goes to the very bottom of the overflow tank.

[Triathletedave]

S

Dave,
A Degas tank, fill tank, and expansion tank are usually names used interchangably.
It is a PRESSURIZED tank with a radiator cap on top.
A degas or fill tank are full if operating correctly. A expansion tank is usually only kept 1/2 full allowing room for expansion.
EDIT: In a normal car, the top of the radiator performs this function. Since the top of the radiator is not at the highest point of the cooling system on and 818, this tank is needed.


A overflow tank is NON Pressurized that hold liquid that has come out of the radiator cap pressure relief valve.
The small hose from the radiator cap goes to the bottom of the overflow tank. When your engine cools, the fluid gets sucked back into the radiator or one of the tanks above. Normally this tank is about 1/2 full.

You need both

Bob

Good to know that I need both. Based on the system descriptions posted here, I assume that both the overflow tank and the degas tank need to be at the back near the engine (high point)? Right now I have the overflow tank mounted on the radiator at the front. If it is too low then it might overflow too easily. I've noticed a huge range in the overflow tank volume in my cold Vs hot tests.

[STiPWRD]

S

Good to know that I need both. Based on the system descriptions posted here, I assume that both the overflow tank and the degas tank need to be at the back near the engine (high point)? Right now I have the overflow tank mounted on the radiator at the front. If it is too low then it might overflow too easily. I've noticed a huge range in the overflow tank volume in my cold Vs hot tests.

Right, my degas and overflow tanks are in the back near the engine and the hoses are capped at the radiator.

[Buzz Skyline]

S

Good to know that I need both. Based on the system descriptions posted here, I assume that both the overflow tank and the degas tank need to be at the back near the engine (high point)? Right now I have the overflow tank mounted on the radiator at the front. If it is too low then it might overflow too easily. I've noticed a huge range in the overflow tank volume in my cold Vs hot tests.

A lot of people delete the overflow tank at the front of the car, but I kept mine as well as adding one to the back (associated with the degas tank as instructed in the manual). The way I see it, the fact that the coolant hoses are low along the side of the car means that there are effectively two high points in the system. The front tank will ensure that there won't be trapped air at the front, and the rear tank handles the trapped air in the back. It's probably overkill, but it's cheap and easy insurance.

[Triathletedave]

I have a couple more questions:

I can drill and tap the high point on the engine for an air bleed line to the degas tank, but what did people do for the overflow line? Do I need to install a pressure release filler cap (radiator cap) at the front of the engine near where the overflow tank will go? Does anyone have pics of how this is set up?

My engine outlet line is so close to the firewall that there is no room for anything but a short 90 degree flex hose down to the rigid breeze tubing. Not sure how anything else can be fitted into that space.

[Bob_n_Cincy]

I have a couple more questions:

I can drill and tap the high point on the engine for an air bleed line to the degas tank, but what did people do for the overflow line? Do I need to install a pressure release filler cap (radiator cap) at the front of the engine near where the overflow tank will go? Does anyone have pics of how this is set up?

My engine outlet line is so close to the firewall that there is no room for anything but a short 90 degree flex hose down to the rigid breeze tubing. Not sure how anything else can be fitted into that space.

Dave
No need for the Drill and tap if you mount the tank right in the main hose exit of the engine.
The pressure release cap will be on the degas tank.
Take a 90 degree 1.5" hose to a degas tank mounted top right of firewall.
Out the bottom of the degas tank to the 1.5" tubing going to the radiator.
Bob

[Buzz Skyline]

Dave
No need for the Drill and tap if you mount the tank right in the main hose exit of the engine.
The pressure release cap will be on the degas tank.
Take a 90 degree 1.5" hose to a degas tank mounted top right of firewall.
Out the bottom of the degas tank to the 1.5" tubing going to the radiator.
Bob

That sounds interesting. I haven't found it in your thread yet - do you have some pics of the set up?

[Bob_n_Cincy]

That sounds interesting. I haven't found it in your thread yet - do you have some pics of the set up?

I have a boosted engine that came with a degas tank.
Dave has a NA that normally doesn't use a degas tank.
There are no pictures, dave will be the first.
Bob

[Lumpyguy]

I am interested in knowing how much air flow goes thru the big side sail vents? I am looking to cut mine and push them in about 2 inches, one reason is to make the side look more agressive as well as open them up for more air flow thru the rear. So other than cosmetic will this help cooling to let more air in.

[Triathletedave]

Dave
No need for the Drill and tap if you mount the tank right in the main hose exit of the engine.
The pressure release cap will be on the degas tank.
Take a 90 degree 1.5" hose to a degas tank mounted top right of firewall.
Out the bottom of the degas tank to the 1.5" tubing going to the radiator.
Bob

I understand the concept, but I get lost when I look at any pictures of degas tanks. Based on your description above, I would need a degas tank with a 1.5" inlet port and a 1.5" outlet port. I can't find any pictures of a tank like this. Where would I find the tank that I need?

[Triathletedave]

Different tactic:

Could I put an inline radiator filler and cap near the engine outlet, and simply run the bleed valve to a rear overflow tank? This seems much more simple to me, since I cannot really fabricate anything myself. I could use a setup like this:
image.jpg

[Triathletedave]

A lot of people delete the overflow tank at the front of the car, but I kept mine as well as adding one to the back (associated with the degas tank as instructed in the manual). The way I see it, the fact that the coolant hoses are low along the side of the car means that there are effectively two high points in the system. The front tank will ensure that there won't be trapped air at the front, and the rear tank handles the trapped air in the back. It's probably overkill, but it's cheap and easy insurance.

Good idea to keep 2 overflow tanks. Since mine is a NA engine, I have no degas tank. I'm now wondering if I really need it. It seems like a lot of extra expense that may not benefit my 2.5 NA setup.

Thoughts?

[TrickyPete]

I have an NA motor and was having the same issue. I put a Barb in the coolant pipe and ran a line off that. (I think this was Wayne's idea). I ran the motor and uncapped the line off the Barb until fluid came out then re-capped it. It solved my issue

[freds]

A lot of people delete the overflow tank at the front of the car, but I kept mine as well as adding one to the back (associated with the degas tank as instructed in the manual). The way I see it, the fact that the coolant hoses are low along the side of the car means that there are effectively two high points in the system. The front tank will ensure that there won't be trapped air at the front, and the rear tank handles the trapped air in the back. It's probably overkill, but it's cheap and easy insurance.

That is what I originally did. However, consider that he two pressure relief caps may/probably-do have different springs and will vent therefor at different pressures and open for "sucking-back" the coolant when cooling down at different negative pressure.........the two tank system can actually preferentially "pump" coolant into one of the tanks. {When the front cap vents first the front tank catches the coolant..........then if the rear cap opens on vacuum first it sucks in coolant from the rear tank}

That is what happened with my setup....rear tank gradually emptied and front tank gradually filled. It could work the opposite way too.

I removed my front tank

fred

[Bob_n_Cincy]

Different tactic:

Could I put an inline radiator filler and cap near the engine outlet, and simply run the bleed valve to a rear overflow tank? This seems much more simple to me, since I cannot really fabricate anything myself. I could use a setup like this:
image.jpg

Dave,
You need some kind of pressurized tank at the top of the system to catch the air.
I'll see if I can find you something that is premade. If not you will have to take a typical tank and have a welding shop put some 1.5" radiator fitting on it.
Bob

here is one off a Ferrari with a price to go with it http://www.ebay.com/itm/Ferrari-Radi...4270df&vxp=mtr

[Buzz Skyline]

That is what I originally did. However, consider that he two pressure relief caps may/probably-do have different springs and will vent therefor at different pressures and open for "sucking-back" the coolant when cooling down at different negative pressure.........the two tank system can actually preferentially "pump" coolant into one of the tanks. {When the front cap vents first the front tank catches the coolant..........then if the rear cap opens on vacuum first it sucks in coolant from the rear tank}

That is what happened with my setup....rear tank gradually emptied and front tank gradually filled. It could work the opposite way too.

I removed my front tank

fred

That's a very good point. I hadn't thought of it. I will probably delete my front tank then.

Thanks, Fred.

-Buzz

[K3LAG]

That's a very good point. I hadn't thought of it. I will probably delete my front tank then.

Thanks, Fred.

-Buzz

Later versions of the manual show a line running from the top corner of the radiator back to the degas tank in the back. FFR also provided hose for this. It came with my kit, #86.

As I understand it, the vent on the radiator at the cap should be capped off and a cap without a vacuum valve should be used. It should also be a slightly higher pressure rated cap then the one on the degas tank, not that it matters if the vent is capped off. Then the line from the corner of the radiator can go back to the degas tank or, as in my case, get connected to the hose from wayne's modification with a T. This allows air to escape from the top of the radiator and it ends up back in the degas tank.

Larry

[Triathletedave]

I have an NA motor and was having the same issue. I put a Barb in the coolant pipe and ran a line off that. (I think this was Wayne's idea). I ran the motor and uncapped the line off the Barb until fluid came out then re-capped it. It solved my issue

I did this as well, but I am worried about air building up again at the high point of the engine. It would be a pain to bleed the system like this more than once. For the time being, I will rely on the single overflow tank until I can get a degas tank solution sorted out.

[SixStar]

We've had great luck putting EWP115s on the 818s. My 818R runs from 187-196 always.