Overheating problems with 95 GP

1995 Grand Prix with a 3.1 V6. It started overheating. I checked the rad cap and it was in pretty bad shape so I replaced it. Then I replaced the rad fan solenoids and had the entire system flushed. The thermostat and water pump were next. Replaced the temperature sensor by the thermostat. Flushed entire system AGAIN 'cause first one wasn't *good enough*.

I have checked the oil filler cap and dipstick and I have no milky deposits. Mechanic tells me the intake manifold is NOT leaking.

The sob still overheats. Any suggestions from the experts here? Is it a head gasket anyway?

Thanks in advance Cliff

Reply to
Cliff
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When does it overheat? Is it while you are driving at 50 miles an hour, or when you are in stop and go traffic? What do you mean by overheating? Is the temp guage just going up further then you are used to, or is it pinned into the red, and boiling over, steam coming out from under the hood..etc? Do your fans come on when you have the a/c on? Do they come on when it's overheating? Have you checked for any blockage of the radiator, or the condensor? Sometimes the blockage can be "between" the rad and condensor.

As you can see, more info is needed.

Ian

Reply to
shiden_kai

Same as the answer I had on Friday:

Could be several things: Air in system. Bad gauge sending unit Bad gauge or things that run/control the gauge Bad thermostat (imo, 3 out of 4 cheap ones are bad) Bad fan(s). (#1 on at ~212-220F, #2 on at ~225-230F Bad fan thermo switch Bad Other things that run/control the fans Low fluid Bad pump And some other bad things.

Reply to
« Paul »

"shiden_kai" wrote in news:%P%

0d.385883$M95.105993@pd7tw1no:

Thanks for the reply Ian and Paul, I really appreciate the help.

Okay, hopefully this helps. Trip begins, city stop and go. Heat gauge will pause on upward momentarily at around 85-95C (100C is boiling pt of water). Then gauge will go to 108 to around 115. Gauge will drop as engine revs up,even below 100. It will jump as I wait at lights etc. Temp can be forced down with neutral revs - but if that goes too long, ie: few minutes, the temp will start to climb again.

I can see the coolant filling up the overflow tank. I don't have A/C on the car, and the one fan did come on around 105 or so. I bypassed the switch on the lower temp fan so it is running all the time now with ignition on.

BTW, I have run the car from cold with the rad cap removed. When it started to warm up a steady stream of coolant came from the open cap. If I revved the engine, the overflow stopped. Not sure what this proves, if anything but thought I'd add it.

I have had the radiator taken out and dismantled and flushed. I am unfamiliar with condensor - do you think this is something that might be connected to my problem?

Reply to
Cliff

Ok, so far what you describe could be fairly normal. What happens if you just let the car idle....does the temp just keep climbing, or will it stop at some point....of course, you are probably are too nervous to just let it go, eh?

Remember, a factory thermostat will open up at about 95C, thats the first pause you are seeing. Then the temp will continue to climb if you are in stop and go traffic will little/no air flow thru the radiator until the temp reaches anywhere from 106C-110C. Then the fan comes one. Never mind about what temperature water boils at, you are supposed to be running 50/50 coolant and water (which won't boil at that temp) and running a good working rad cap which should allow the cooling system to achieve 15 psi pressure (which also suppresses water's tendency to boil) so running up past 100C is no problem with a properly working cooling system.

If all things are working properly this isn't needed. If you have an actual problem, this won't help. In other words, it's a waste of time to make the fans run all the time.

This can be normal....but it might be an indicator of a head gasket problem. There are better ways to test for a head gasket problem.

Since you said you don't have air conditioning, you won't have a condensor. So it's irrelevent.

Check the coolant level when it's cold, make sure it's completely full at the radiator when cold. Start the engine, let it warm up...see if it builds up pressure in the hoses rapidly. If you get pressure quickly in the cooling system, you may have a head gasket problem. Watch the overflow bottle, once it's warmed up, can you see bubbles continue to come through the coolant in the overflow bottle? Sorry, it's hard to diagnose things like this sight unseen. Much easier when you can watch things happen.

Ian

Reply to
shiden_kai

I just finished diagnosing a similar prob with my 95 Grand AM L6 FWD. I noticed some coolant leaking around the coolant resivor cap. I have since disassmbled the cap & found the gaskets & springs were worn/old/craked & had shifted. I replaced it with one from a junk yard. The water around the cap dissapeard but I still was overheating & loosing coolant. I noticed coolant around my firewall next to the heater core inlet & outlet, but not from the connections. There is a rubber elbow that is between & below the connections, it seams to be an overflow hose for the heater core housing.

I decided to try a little experiment & bypassed my heater core. had a little trouble since the hoses were diffrent sizes. Since I havent had any overheating & no coolant loss.

You my want to give this a shot since it looks like you've tried about everythin eles.

which leads me to MY problem now. I have totaly dissmantled the dash in an attemnt to replace the heater core & I am trying to remove the center console where the shifter is located & I can only find two bolts in the arm rest/storage cubby. I am affraid to pry at any of the plastic. Anyone know how to remove it & the shifter??

Reply to
Flack

I just finished diagnosing a similar prob with my 95 Grand AM L6 FWD. I noticed some coolant leaking around the coolant resivor cap. I have since disassmbled the cap & found the gaskets & springs were worn/old/craked & had shifted. I replaced it with one from a junk yard. The water around the cap dissapeard but I still was overheating & loosing coolant. I noticed coolant around my firewall next to the heater core inlet & outlet, but not from the connections. There is a rubber elbow that is between & below the connections, it seams to be an overflow hose for the heater core housing.

I decided to try a little experiment & bypassed my heater core. had a little trouble since the hoses were diffrent sizes. Since I havent had any overheating & no coolant loss.

You my want to give this a shot since it looks like you've tried about everythin eles.

which leads me to MY problem now. I have totaly dissmantled the dash in an attemnt to replace the heater core & I am trying to remove the center console where the shifter is located & I can only find two bolts in the arm rest/storage cubby. I am affraid to pry at any of the plastic. Anyone know how to remove it & the shifter??

Reply to
Flack

"shiden_kai" wrote in news:gZr1d.4372$%S.957@pd7tw2no:

It does seem to pause around 95C, and then climb to 105 or 110 in stop/go traffic. If I go into neutral and rev to 2,000 I can drive the temp back down to around 80 or so. If I have to do this too long...few minutes...the temp will climb again.

Technically speaking I have A/C, it just doesn't work. The bearings on the compressor are quite loud, but I doubat that has any bearing on this problem.

up...see

Would a pressure test on the cooling system help to narrow down the problem? With the latest attempt to resolve the problem with the rad removed, dismantled cleaned it seems to have improved things somewhat - but it could also be cooler weather.

But the temp. just seems to jump all over the place and doesn't stay steady which really doesn't seem normal to me.

Cliff

Reply to
Cliff

did you bleed the cooling system when you filled it?

Reply to
gtoed

ther should be bleeder valves on thermostat housing or the water pipe for the heater hose.air blocks in cooling systems can be hard to get out sometimes

Reply to
gtoed

"gtoed" wrote in news:997c0cdd1f5dc4a51f0ef530c724acd6 @localhost.talkaboutautos.com:

Yes, the problem is solved, but unfortunately the problem was a head gasket...ouch!

Reply to
Cliff

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