Maybe you all can give me hand w/a GM thats running hot/overheating. I have looked in other forums but they are as helpfull as a fly in labor! My buddy has a 1989 Olds 98 V6 200K It is running hot and has overheated 1nce. We replaced the thermostat and cap and fixed a leak in the overflow tank. It still runs hot 200+*. Everything else seems to be working, what am I missing?

 

Test the coolant?
Is there Bar's leak in there?
if the radiator has slime inside it, it will not cool either.

 

Thanks Talyn. The coolant looks good. The thermostat opens around 190+ ish (I think). The top hose get hard and hot when the thermos opens, then cools down and and gets squishy when it closes. The fan (electric) runs OK and seems to cool it down to 190 something. This all started when it overheated. I noticed the overflow bottle was cracked I fixed it with some epoxy. I thought that would fix the running hot problem but it didn't. So we replaced the thermostat and cap and still no help. I spose we will look at the coolant and see if it os OK with a tester but I don't think it is the problem. There me be another valve or something that I am not seeing. The blows good and hot. Any other suggestions?

 

Pressure test the coolant cold then hot. See if it holds.
Could be a head gasket.

Bill

 

We are going to start on this project back up later in the week. I will get a pressure tester from work and see what happens. I assume if it looses pressure with no leaks a head gasket may be bad? I hope not. I am also going to get a infared laser tester and test the temp at the thermostat. This particular vehicle ALL digital, not 1 **** on the whole dashboard. I have some more places to look now.
Thanks!

 

The reason I said test the coolant is, I never knew this till yesterday, but too much water or too much antifreeze and you loose effectivness eitherway.

 

From what understand about the mixture is: Too much antifreeze will not conduct enough heat to the surface areas to help dissipate the heat (straight antifreeze will cause overheating). Too much water and well, it will freeze (32* and water will freeze). I am old enough to know I don't know chit. Is this right?
I think we will start with that. Drain it and mix it right/screw the testing. Thanks Talyn!

 

probably needs a good cleaning inside.

 

is all the air out of the system some of those v6 engines had air bleed screws?

 

Its a GM. What do you expect? Tell him to trade for a ford. imho

 

He has a 97 Ranger....but he is also a Dallas fan go figure!? But he is still my buddy and I have to help him out, lol

 

I will look for some air screws/bleeders but I think Talyn could be right/just bad mixture, we'll see

 

I understand completely. Just giving crap. Does he ever lose water or just get hot? If he does and it isn't going in the oil could it be a head gasket from when it overheated before leaking into the exhaust?

 

He hasn't lost water since we repaired the overflow tank. No "chocolate milk" in the oil, no "steamy exhaust" . still has the same amount of coolant.
I hate to bring a GM in this fine forum but I can't get answers or even responses anywhere else. I appreciate everyones input! I just want to make sure I am not missing anything obvious.

 

don't rule out a bad thermostat, I am on my 4 th one in my service truck in less than a month. one stuck open one stuck shut one ran hot.

most gm V6 engines have bleed screws on the coolant system, if not bleed the system will vapor lock.
as far as a perfect mixture of anti freeze it isn't totally critical, maybe a few degrees?
I would run strait water until I found the problem unless it is going below freezing at night and the car has to be outside.
I would also buy a flush "T" and flush the system!
I also would NOT replace the DEX-COOL, it is corrosive and there is a lot of aluminum (this from a gm tech and my cousin who was a pontiac tech)