Overheated - benign fluke or disaster?

[Michael]

On the first urban-traffic shakedown run after some tuning, the coolant temperature suddenly started climbing from 190 to 200, 210, 220, 230 - before I managed the nerve to shut off the engine the temperature hit 235, bounced down to 230, then back to 235 - and this lasted for maybe 2-3 minutes. Perhaps less, but it felt like 2-3 minutes. When shut-off, the temperature needle was stubbornly parked at 235. I had to restart the engine to get out of traffic - another 30 seconds of operation at 235. Then final shutoff.

 

It turns out that the V-belt (connects crank pulley, water pump and alternator) had come off, and I was driving for about 1-2 miles without a water pump. No steam or visible damage. After returning from the local parts store with a new belt, the temperature cooled down to about 150. After reinstallation of the belt I commenced the rest of the drive. Temperature steady at 190, no smoking, no bucking, no surging - at least, none that could be discerned over the exhaust noise.

 

This is a nearly brand new engine - 10 miles on the odometer.

 

So, question: given the description above, how likely is serious damage? Or is the only real damage to my frayed nerves???

[jakeshoe]

Michael,

Late model GM engines do not turn the fans on until 224*, these often have aluminum heads, etc.

235 is a bit warmer than I would like to see on a fresh combo, but you are probably OK.

My main concern would be where is the temp sender located and is it in a cooler spot than the hottest part of the engine.

 

i.e. No water pumping, the hottest portion of a SBC will be the center of the exhaust side of the cylinder head.

If your coolant temp sending unit is located in the head, you were probably getting a fairly accurate max temp reading. If it was located in the intake, you were probably 15-20 degrees less than max, and if in any other location, it wouldn't give a good indicator of the temp.

[80LS1T]

I agree, I really doubt you did any perminent damage. When I first got my eninge running I did pretty much the same thing because my fan didnt kick on. My temp got up to about 225-230 before I shut it down. I have not seen any symptoms of any sort of damage.

 

A buddy of mine who races oval dirt track see's those temps pretty often and his motor is still running strong.

 

I wouldn't loose sleep over it!

 

Guy

[Mikelly]

Bigger question is why the belt got tossed. Check the alignment of the pulleys and then I'd also go ahead and replace the t-stat just for peace of mind. Since the belt was tossed, I'd inspect (Actually, no. I'd personally replace it) it for tears or damage.

 

Mike