The Stovebolt Site Forums The Shop Area Engine Shop Overheating in drive through..

Hey guys, my 235 engine overheated when I was sitting in a drive through on a hot day. It’s a rebuilt motor with 10k miles and runs great. Temp gauge went to 230, I then replaced the thermostat and has been running around 190. A month later it went up to 210 when I was sitting in traffic, as soon as I started driving it went down. Radiator is not clogged or leaking and went through at shop 10k ago as well as new water pump, which is not leaking either. I read manual and said to also check fan belt which looked ok but I will replace anyway. Any other ideas, thanks?

Did it boil or just show hot on the guage? What pressure cap do you have?

Ed

We don't know the year of the truck nor the engine. Fan location? Low? Center of radiator? Any shroud with it? Distance from radiator? I'm assuming fan connected to water pump. Please give us more info and we'll be happy to give you a more thoughtful answer.

7 lb radiator cap. 57 Chevy, fan is center and no shroud, fan is connected to water pump.

Not sure if boiled just showed hot on gauge.

You don't have a problem, but you can examine Possibles.

1. Water pump failing
2. Pulleys/belt slip/stretch
3. The radiator you think is not clogged
4. Hose collapse
5. Cap failing
7. Low oil
8. Too much antifreeze
9. Faulty gauge. Based on the fact you don't say it boiled over
10. Timing set
11. Fan blade set at 1/2" clearance to Rad
12. Normal. Based on the fact you don't say it boiled over. 210 is not dangerous with no boil over- 7 lb cap/Sea level. You are at 167 feet above.You are OK. Don't go past 230 F. Run high idle to cool, when stuck at McDonalds. That works. You are in the 100 deg range at your location. Official temperatures are taken in the shade.

I will check thanks

no shroud

I have two trucks that have not been started in weeks, Both have the hood closed. One in the sun, one in the shade. As they sit, the head temp is 111 and 104. If you are going down the road here, the incoming ram air into radiator is 150-200 off the blacktop.

I suspect that you may not be running at 230 degrees with a 7 pound cap without some discharge from the overflow down pipe.
Assuming that you are using an electric gauge, I would suspect that it may be defective. The easy check would be to replace it. Easy to do and inexpensive (as far as I know?) You could use an infrared temperature checker, but I don't know where to tell you where to aim it to verify the correct temperature.
Carl

It won’t help fix it, but if it happens again, try turning your heater on. That has worked for me when the temp starts getting a little warm.

Lee.

The posts above provide a good list of possibilities/causes.

Carl brings up a very good point/consideration.

Probably not the cause, but, was the engine block/head internally cleaned (and, how) when it was rebuilt?

To me it sounds like a lack of air flow. You could try moving fan closer to radiator, add a shroud, or add some Water Wetter additive ( race car coolant additive ). On hot days, leave more room in front when setting in lines, it does no good to suck hot exhaust into the radiator.

So you replaced the thermostat and then it went up to 210, so what is the problem? 210 is not a problem when you have at least a 4lb cap and a 50/50 anti freeze mix. You said it moved down after you started moving so I wouldn't be at all concerned at this point.

7 psi cap was standard equipment.

160 degree thermostat was standard equipment - fully opens at around 180 degrees.

Good advice is posted above.

How about finding a more aggressive fan or a smaller pulley.
George

I got a high flow thermostat at auto zone. they carry a 160 and a 180. I just change to 180 for no particular reason. I do not have a stock radiator.

It was rebuilt 10k miles ago, I just replaced the cap and will buy a new gauge too.

Sean e
Are you getting the message that you do not have a problem at 210 deg or are you not getting the message?

Meaning that the engine is not actually overheating?
It will knock under load whenever that temperature is reached, but you may not hear it (and ignore the damage).
That temperature is not the water temperature everywhere inside the engine. I assure you that the water closest to the exhaust ports, exhaust valves and spark plugs is much hotter than 210, and is only prevented from boiling where it it (not in the radiator) by cap pressure.

Yes, this is my opinion, meaning that the engine is not overheating from what I read. In the context of: time period of 210, duration, fairly easy and quick cool down, summer temp, sitting still, not boiling over even after shut down and no known design changes since last summer or 10K miles. It is normal for those conditions and will not damage.


Whatever other areas you are speaking about are present in all trucks and their gauge readings, gauge tolerance/calibration/quality.

Yes the temp inside the motor can get over 212, that's exactly why the system is pressurized. The cap is designed to control boil up to a designed safe level of heat. It is a pressure relief valve. The steam release is a designed-in signal of overheat, if you didn't see the gauge, and protects hoses and radiators from blowing up hopefully. You turn off the motor ASAP.


10,000 miles can be considered a lot of miles on some rebuilds.

So, why do modern engines turn the electric fan on at 220 degrees, boil over at 260+, and use a thermostat that keeps the coolant at a minimum temperature of 195? I guess all of them are knocking under load, and destroying themselves? My Ram 1500 is coming up on 200K miles of operating under those conditions.
Jerry

Why have I not asked what temp thermostat is installed? Shame on me.
Sean e.....Tim says 160, many use 180..........190 probably not good.
Also, shut your truck off in the summer and go inside to order.

I had a 160F for years but replaced it with 180 last week. I have not had any overheating problems. It is 83F here today and the temp gauge went to 200 sitting waiting to merge with traffic. Has soon as I starting to move it came back down and that is good. But it did worry me for a while. I do have an electric fan. I don't know if it was my imagination or the fact there could be some stray antifreeze on something because I smelled it.

This post has been Hijacked. Confusing as to who is talking to whom. Separate problems, from separate people, need a separate post.

They will also act this way if the coolant level is low. Have you checked for leaks?