What water temperature is to high?

[bhanshaw]

Have a 3.1 Roadster with a Ford Racing 302 and the Factory Five gauges (Celsius). Been driving it for some time and usually the gauge barely gets off 60. 80 max. This week the gauge got up to 110 Celsius - should I be worried? When does the red zone start?

[CDXXVII]

110C = 230F. You are in the red at that temp IMHO. Depending on your operating pressure you may be pretty close to boiling over.

Operating between 60C and 80c seems too low.

I’m happy around 90C-95C

Above 100C is where I start paying attention.

[GoDadGo]

As CDXXNII stated anything above the boiling point, 100-C or 212-F, really requires your attention.

Questions:
1. Do you have a fan shroud, or is the fan mounted directly to the radiator?
2. Is your fan functioning and if so at what temperature is it turning on?
3. Do you have a manual override for your fan?
4. Could your thermostat be stuck?

Good Luck From The Dark Dart Side!

[Jeff Kleiner]

110C/230F is way hot, indicative of a stuck thermostat or worse. If your cooling system is operating correctly it should sit right on your thermostat temp; for a 180 degree stat you'd see ~82C and for a 195 it should show ~90.

Jeff

[RickP]

When it went to 110C, what action happened to allow the temp to come back down? Or did it? If your thermostat is stuck, there is nothing preventing your engine temp from climbing other than ambient air temp. If the gauge temp came back down after a period of time, could just be a big air pocket in your cooling system. In either case, you need to address the problem.

[ThickCobra]

I have a 180 stat and find if I sit in downtown traffic my temp can rise to around 95 - 100 centigrade. Sounds like I have a possible issue with my thermostat and a new one will be going in this week. My fan runs fine, I even installed an override switch under the dash and I have no leaks nor fluid loss due to any head gasket issue.

My FFR gauges read in centigrade so thanks for the farenheit to centigrade conversion.

Jay

[NAZ]

Keep in mind that T-stats are typically rated at the temp they START to open (as opposed to fully open).

[bhanshaw]

Thanks for your reply - very happy!

[bhanshaw]

Thanks for your response very helpful! Do not have a fan override switch. Will have to look into that!

[bhanshaw]

Thanks for your response. The gauge dropped back down so must be an air pocket. I went ahead and pulled the stat - it did open.

[bhanshaw]

Thanks roe your reply. I think I had an air gap issue but also think my stat was wronky as for the past year or so it rarely got off 60 unless I was stopped for a long time.

[Big Blocker]

Quote: "also think my stat was wronky as for the past year or so it rarely got off 60"

I have that same issue . . . for the past year, my gauge reads just about 60-65°C (140-149°F) as soon as the engine warms up. Stays there in traffic with the fan on and out on the highway with the fan turned off. At first I thought it might be a bad gauge but tested it out of the engine water stream and it works perfectly (early Autometer "Classic" gauges from f5). I'm about to pull the t-stat because I believe it is stuck open part way (not regulating). My radiator is more than capable of cooling the engine at any running condition, I depend on the t-stat to maintain the temp. Factory EFI engines call for a 192°F stat which transposes to 88°C on my gauge.

Doc

[NAZ]

Doc, I'm sure you know this as many others out there also know but many more may not. A T-stat has two primary roles; to help the engine warm up faster and to control the operating temp by modulating the coolant flow. A 180-deg T-stat will start to open when the coolant temp directly in contact with it reaches 180-deg (+/- a few deg) and will be fully open allowing max flow at 15-20 degrees above the 180 rating. So a T-stat will help control the operating temp but only up to the point it is fully open, after that the operating temp is affected by the BTUs being generated, the outside temp, and the radiator's ability to shed that heat. In the 180-deg example the T-stat can only control the coolant temp between ~180 and ~200. Keep this in mind when troubleshooting coolant temp issues.

[BEAR-AvHistory]

My COYOTE runs 82C (180F) both oil & coolant. Sitting in stopped traffic in the mid to upper 35C (90'sF) summer weather the coolant will go to 93C (200F) but a block or two of movement will bring it back down.

Have Everson & Breeze sheet metal in the radiator intake tract & no fan shroud or oil cooler. The engine thermostat is whatever FORD puts in their engines during assembly & coolant is FORD's

[SSNK4US]

I have a question that is kind of on the same line but not really... and maybe kinda stupid. I’ve seen threads talking about swapping them out but never a reason why FFR temp gauges are C not F.
Because AC was British?

Kurt

[wallace18]

That is how the original gauges were. Hence the name vintage.

[AC Bill]

I can actually see exactly when my T-stat opens, if I monitor the gauge closely. (Classic Instruments). The temp needle climbs and climbs, at a slow but steady rate, till it passes by the 185F mark on the gauge. Then the needle slows in it's upward climb, and then seems to hover for a minute,, as the T-stat is opening. Then the needle will drop back, just a hair. I presume that's when the T-stat is fully open. It will stay at that temp, as long as I'm not stuck in traffic, or unless I start driving it pretty hard. If it gets up to around 195F the fan kicks in, and it brings it back down to around the 185 mark pretty quick.

[Vegasjack]

Just FYI. I used a little bit of my wife's (haha) red fingernail polished and put a little red dot at the 85 celsius, whis is 185 where my fan should automatically come on and another dot at 100 Celsius, where I would seriously start worrying and maybe even pull over. Like you, my guage wants to stay around 70c most the time. I thought guage wasn't working properly for awhile.

You can always use a razor to remove dots at a later time. Trust me, it really helps when you are not use to celsius and your flying down the freeway at 70 MPH.

Jack Lundquist
Las Vegas, Nv

[SSNK4US]

That is how the original gauges were. Hence the name vintage.

I figured vintage meant the style, like Stewart Warner looking. Never thought of C as vintage.... sorry my bad.

Thanks

Kurt

[danielt]

Just for reference, Ford Fuel Injected 302 in cars with electric fans, the ECU was set to turn on the low speed fan at 220F, High speed fan at 240F, and that's with a 195F thermostat.
Since I'm using the Ford Racing harness which adds fan control capability to the Mustang ECU, I've programmed mine to come on at 195F when using a 180F thermostat.

[Big Blocker]

NAZ,
I love it when someone who knows what they are talking about shares their information with the rest of this forum.
I agree, there are quite a few that don't understand the concept of a t-stat and your explanation is spot on . . . I'm positive it will help many newbies, and maybe even some 'ol guys better understand cooling systems better.

FWIW, my "problem" (if you want to call it that) is that my radiator is over-kill for my engines HP output and will keep it at about 50°C with the t-stat removed completely. That's why I think my t-stat is stuck open right now, or almost completely open. It takes forever for my engine to get the gauge to start reading and never gets above 63°C. Last year, when I believe the stat was still functioning properly, my gauge stayed at 88°C - telling me that the stat was working correctly at maintaining the temp.

Summer is here, gunna be a bit before I want to work on the car in the hot Vegas heat . . .

Doc

[NAZ]

I love Las Vegas -- but the heat, not so much. The high was 50ish here today -- t-shirt weather for us. At least the failure mode on yours is less troublesome in warm weather than it would be here.

Have fun.

[broku518]

I grew up in Europe, so C doesn't bother me at all.
My stays around 80-85, seldom goes to 90 (only if I am stuck in traffic)

I am having hard time with F, the number is so high, yet it isn't problem. In C, all I know is 100 is a trouble :)

[NAZ]

Most out there only have to worry about boil over but for some of us with higher dynamic compression ratios, 190F (88C) can result in detonation. So since these cars are all custom built with a variety of engines and parts configurations there is no "one size fits all" max temperature like you might find in an OEM car. Even at this altitude (you can get away with more in thin air) and a 90F day I have to mix VP 110 in the tank to prevent pinging where most of y'all would be merrily motoring down the highway with the wind in your hair (or what hair you have left). Just another thing to consider when building a custom built car.

[bhanshaw]

Appreciate all the feedback I have received from everyone. I added a new 90 degree celsius (195 F)stat and tried it again. With idling start the fan came on around 65 degree Celsius and stayed on. Took it out on freeway and it soon climbed to 100 degree C and stayed there and maybe got up to 105C . I will try more burping but feel this is to high. I went from five years driving it at 60 C to now at 100 C - frustrating!

[Richard Oben]

One thing people have not addressed is Under drive pulleys. They are great for a few HP at 500 rpm but DO NOT move enough coolant when stuck in traffic. If stuck in traffic with under drives rev the engine and keep the speed up as opposed to idle. On a street car we never put them on too many issues. JMHO. Richard.