howdy all
i have a 1989 corvette that is getting hot according to the guage.it also must have a safty that also shuts the engine down when it gets too hot because the engine shuts off.
the guage will show 296 degrees and it shuts down.
it doesn't seem that hot to touch the valve covers.
it also does not boil over the radiator hoses feel cold to touch.i put a new thermostat in it and a new radiator cap because it's center rivit had come out leaveing a small hole in center of cap.all belts are good and turning.this is stumping me .anyone know whats wrong here??

thank you
jeff korner
southeast indiana

Jeff,
I don't know much about vetts, but if the hoses are cold it sounds like the coolant is not circulating. Could you have a collapsed hose or bad water pump?

howdy ed
hoses seem fine and the only way i have seen water pumps go bad on other vehicals i have had is that they start leaking externaly. this has really got me puzzled. it's almost like the impeller is broken inside the pump.i'm not sure it's even over heated,the gage says so but the engine seems ok.

jeff

Have you looked in the radiator with the engine running to see if the coolant is circulating properly??

I was going to suggest the same thing. Start the car cold, with radiator cap OFF, stick your finger in the water. See how long it takes before it gets really hot.

howdy dog
the coolant is not circulateing, new thermistat, hoses are cold, gage says 296 degrees which is 84 degrees over boiling
something should be seeming hot.i think gage is wrong and sencor or something is shuting engine down.these newer cars with this computer junk stinks.

jeff

If your coolant is not circulating then that is why your engine is overheating. Definitely sounds like you have a water pump problem or a possible blockage in the cooling system.

Based on your description, I would suspect the gauge.

You must have water circulation.....pull the pump..pull the radiator...forget the sensor, it's working...New engines about 7000.00

If it was getting that hot it would puke it out the overflow or the radiator if the cap is off, when you shut the engine off. How long does it take for the gauge to read that, and will it do it at idle or do you have to drive it?
I am not sure if that year uses the same coolant sensor for the computer and gauge but I would want to use a scan tool to see what the computer is seeing. Cold the Intake air temp sensor and coolant temp sensor should read
within a few degrees of each other.
Another check you can do is turn the heater on high and see if it takes longer for the temp to rise.
In all my years in the shop I do not remember ever seeing a small block water pump impeller come lose.
Was any engine work done prior to this problem?
A wire to the sensor that may be going to ground as it heats will cause the gauge to read hot.

Their is a specific procedure to change the thermostat/replace coolant in these models.

The front must be jacked up approx one foot off the ground, otherwise the cooling system WILL BE air bound.

I would start with burping the cooling system, and then verify the proper operation of the temperature gauge. If the sensor is in an air pocket - it will not function properly.

296!? What was the oil temperature?
I won't get alarmed until I read that as well.....

Jeff,
Until you actually shoot the engine and radiator with a temp gun you are not going to get much accomplished.Hit the gun on the thermo housing,upper hose at radiator mid radiator then lower hose.

Is it at all poss you have the thermo installed upside down??

Also,a temp sensor going bad will send false signal to ECM,which controls the temp guage and safety. Hope this helps,Jim