Overheated, Fan issue, Radiator

[ylbill]

Check the ground coming off of the fan switch. Its connection is over in the cluster on the driver's side fender well. The switch input side from the fan is always hot, the switch gives it a path to ground. Thus it can run when the ignition is off.

Thanks, done for the day. Will check it out tomorrow.

[nelsonj]

It almost certainly is the ground. Clean the connection on the ground pod. There should just be one wire that leads from the thermo switch to the ground. If that doesn't work, add a new ground wire.

[ylbill]

Excuse the dumb question, but would it still be a ground issue if when the fan wire connectors are shorted together in turns on?

[ylbill]

sorry, ignore this post. i meant to edit last post.

[RRoller123]

If you short across the fan switch and the fan turns on, then either the fan switch is bad, or it isn't getting up to temperature because of air blockage in the radiator.

[ylbill]

If you short across the fan switch and the fan turns on, then either the fan switch is bad, or it isn't getting up to temperature because of air blockage in the radiator.

This is becoming more of a mystery now, because I just installed a new switch and checked bottom hose and it was hot. I do believe the original cause was air blockage, which resulted in overheating, but have been checking that hose along the way and it has been circulating through that bottom hose. Thanks for all the input guys. Not sure where to go from here?

[RRoller123]

How hot? It should be too hot to hold. If it is not, still probably air in the system.

[ylbill]

How hot? It should be too hot to hold. If it is not, still probably air in the system.

Okay that I haven't paid enough attention to. Will be my next test. Thanks!

[RRoller123]

To be absolutely sure, jack the front end way up so that the fill plug at the union up front is the highest point, and massage the various hoses to work out all the trapped air. Make sure that the TStat is in the right orientation too. That would send coolant the wrong way and cause overheating of the engine, and likely under heating of the radiator.

[ylbill]

To be absolutely sure, jack the front end way up so that the fill plug at the union up front is the highest point, and massage the various hoses to work out all the trapped air. Make sure that the TStat is in the right orientation too. That would send coolant the wrong way and cause overheating of the engine, and likely under heating of the radiator.

The Tstat hasn't been touched and the car has only had fan issues because of trapped air. I would burp the system and the fan would work fine. It's only since the car overheated that I'm having a fan problem not coming on even after burping the system, which is why I changed out the switch. I needed to do a flush anyway, so it worked out. I'll try to clear the air again when I get a chance and pay more attention to how hot the hoses are. Thanks

[RRoller123]

Maybe there is a small in-noticed leak somewhere? Does the level drop slowly over time? A slow leak will let air slowly in.

[ylbill]

Maybe there is a small in-noticed leak somewhere? Does the level drop slowly over time? A slow leak will let air slowly in.

Not that I can visually see. I did block test after the overheat and no color change. I'm not real experienced in engine mechanics. Can do the basics. I enjoy driving it much more than working on it. Going to burp it, check fluid level and see how it goes from there.

[ylbill]

Maybe there is a small in-noticed leak somewhere? Does the level drop slowly over time? A slow leak will let air slowly in.

Not that I can visually see. I did block test after the overheat and no color change. I'm not real experienced in engine mechanics. Can do the basics. I enjoy driving it much more than working on it . Going to burp it, check fluid level and see how it goes from there.

[RRoller123]

good luck!

[ylbill]

Okay, the bottom radiator hose is cold. So I jacked the front up, squeezed the bottom hose many times and cannot get the air blockage cleared. Have done this a couple of times before with any problems. After 10 or so pumps and it clears. Anyone else have this problem? If so, what cleared it? Thanks