Engine overheating

[Ron R.]

This was never a problem before, but after the car has been siting for a while, I decided to finally fire it up and see how it's running, but first I changed the anti freeze and thermostat. At first I thought maybe the thermostat was bad, but after checking in water it opened up at about 190 degrees. So I can discount the thermostat. Is there something else I can maybe check.

Ron

[Harry S.]

Re: Engine overheating

You may have an air bubble stuck. Strange as it seems this can happen. Drain the coolant again and if it's clean put it right back in again.

But, is it running hot or is the needle pegged on the highest temp? If yes, it may be the sending unit. My sending unit went this summer 3 days after I changed all the coolant.

[Timothy B.]

Re: Engine overheating

I would fill the expansion tank to the top and install the cap then run the engine for a while and see if it settles down. Don't remove the cap until it's completely cooled down to recheck the coolant level.

[Ron R.]

Re: Engine overheating

Thanks for the information, I will check items listed. Also, I noticed that the upper radiator hose was not hot,but the temp gauge was at about 240 degrees before I shut it down.

[Michael H.]

Re: Engine overheating

Thanks for the information, I will check items listed. Also, I noticed that the upper radiator hose was not hot,but the temp gauge was at about 240 degrees before I shut it down.

Ron I assume you installed the thermostat correctly, if it is then you have some air in the system.

Mike

[Terry D.]

Re: Engine overheating

Did you check the hoses with an IR gun? If the needle was at 240 did you notice any overflow? From the sounds of it ( upper hose not hot) it is probably your gauge. Again easy way to test is with an IR gun

[Michael J.]

Re: Engine overheating

Air bubbles are the reason I always drill a small hole or two in a new thermostat.

[Michael W.]

Re: Engine overheating

Sounds like the thermostat was installed upside down.

[Francis F.]

Re: Engine overheating

I would strongly advise you to invest in a balancing T-Stat.would aid in getting air out,and engine will run cooler.
Francis

[Ron R.]

Re: Engine overheating

That did cross my mind about the thermostat installed incorrectly, but I've done this many times before in the last 50 years. I think the problem may be as you mention, air in the system.

thanks,

[Ron R.]

Re: Engine overheating

Please explain what a balancing T-stat is? not familiar what this is.

Ron

[Joe R.]

Re: Engine overheating

Please explain what a balancing T-stat is? not familiar what this is.

Ron

Hi Ron,

I have seen John Hinckley and others recommend the Robert Shaw thermostat. I believe the part number is 330-180. I don't know if it's balanced or not. I think the chief advantage is it won't fail stuck shut.

Joe

[Leif A.]

Re: Engine overheating

Here ya go!! Robert Shaw #301-180

http://www.stewartcomponents.com/index.php?route=product/category&path=61

[Duke W.]

Re: Engine overheating

This was never a problem before, but after the car has been siting for a while, I decided to finally fire it up and see how it's running, but first I changed the anti freeze and thermostat. At first I thought maybe the thermostat was bad, but after checking in water it opened up at about 190 degrees. So I can discount the thermostat. Is there something else I can maybe check.

Ron

It would really help if you specified the year, engine/drivetrain configuration and any modifications.

Also, you need to be specific about "overheating". How high is the temp. gage reading and under what driving conditions?

Have you verified temp gage readings with IR gun readings of the thermostat housing and radiator outlet hose?

Emission controlled engines are purposely configured to run "hot" and exhaust manifold temperatures may run 900-1000 F degrees at idle due to severely retarded total idle spark advance to increase EGT in order to oxide CO and HC in the exhaust system, but this also places a substantially higher load on the cooling system. Non-emission controlled engines with optimized total idle spark advance usually show exhaust manifold temperatures at idle of no more than 500 F.

Without more specific information all anyone can do is just guess from a myriad of overheating causes.

A configuration audit along with some simple tests allow one to follow a logical troubleshooting procedure, discussed here in dozens or threads, to isolate and correct the problem.

Duke

[Michael W.]

Re: Engine overheating

The Robertshaw units are nice, but won't solve the OP's problem. Their sole advantage is less probability of failing closed.