Help! over heating

[jerry c]

Good morning everone, I'm Aa new member. I just purchased an '81 vette in may. had all the body work done and painted.Drove it 1 day, went to go for a ride the next day and got a 2 blocks down the rode and temp gauge was all most to 260. Here is what I have done so far. Checked cooling fan motor directly across battery and it runs, replaced thermostate, checked cooling fan sensor it never opened when temp guage reached over 200. Replaced sensor, still over heating.Any ideas other than maybe the water pump? All and ny help would certainly be appreciated. jerry c

 

[Hib Halverson]

If the gauge was almost at 260, the cooling system was no only overheated but it should have boiled over.

Did it?

If it didn't, have you checked the temp gauge against a known, good gauge?

Also, if you drove only two blocks and the engine was at 260 deg. coolant temp, either the gauge is no good or you have a very basic problem with the cooling system such as little or no coolant in the system, no coolant circulation (look for a water pump with a damaged or spun impeller) or a total or near total blockage somewhere in the system.

 

[Peer81]

Maybe stupid but when cold is the radiator filled to the top?
If so is the air flow blocked between the airco thing and the radiator?
And like Hib say's don't only look at the coolant temp gauge but at 260 other things should show the 260 temp.
Good luck!

Greetings Peter

 

[bill81vette]

do you have any thing to stop the air flow as it is going over the radiator???
the air flow needs to go thru the radiator...



BTW Welcome to CAC!!!
enjoy!!

 

[jerry c]

Thanks Hib, Peter, and Bill, doesn't boil over radiator is always ool actually cold. Haven't checked gauge, radiator is full when cold as is bottle.Not stupid peter good question, one I hadn't thought about , but yes radiator full. Not sure what the airco is.nd as for the airflow Bill, I don't have the air dams on yet, was waiting for the painter tyo buff car out6. so could that be a problem? I really appreciate all the help guys. It's been a long time since I tried to be a shade tree mechanic. Looks like I have forgotten the basic trouble shooting skills. will check everything all of you have mentioned.
Jerry

 

[Hib Halverson]

If the radiator is cold–not warm/hot–but cold and after running a short time the temp gauge is pegged, I'd look for a blockage, failed water pump or a stuck thermostat. Check the 'stat first.

 

[Peer81]

Now I think about it, maybe air is trapped in the enige where coolant should by. As the sensor is in the head and maybe the coolant level in the block is lower than that. This could rais the coolant temp gauge very quick and the coolant in the engine still being "cold" (same for the radiator).

Greetings Peter

 

[Vettehead Mikey]

Try running it with the rad cap removed. There should be visible signs of flow even at idle speed. Coolant should be too hot to touch with a finger. Have a helper monitor temp readings.

 

[catbert]

Now I think about it, maybe air is trapped in the engine where coolant should by. As the sensor is in the head and maybe the coolant level in the block is lower than that. This could raise the coolant temp gauge very quick and the coolant in the engine still being "cold" (same for the radiator). Greetings Peter

ding, ding, ding. I think we have a winner. Look for an air-block

 

[jerry c]

Over Heating

To Hib, Peter, Bill, Vettehead, And Catbert,
Thank you for all the suggestions and advice. I suspectad more than 1 problem because I tried everyting except the water pump. I think there was an air pocket but I also found the tempature gauge sensor to be bad. So after flushyng the radiator and blocvk out, also replacing the sensor, my problems with heating are solved.Thank you all again. Got to take my first ride in her what a joy.
Jerry