Overheating issue

[trigga_b]

I'm trying to help my cousin diagnose this overheating issue he has with his 92 SSE. It engine never reaches the 280 degree mark, but only enough to display the check engine light. This occurs slowly when stopped or parked, but it's worst when you drive. There is coolant in the system. I just changed the thermostat and it didn't help. After driving I took the radiator cap off and touched the coolant, which wasn't very hot. I also noticed that after letting the car run and overheat, I can hear the coolant bubbling in the top radiator hose and by the water pump, BUT the coolant in the radiator isn't that hot. ALSO, most of the coolant ends up in the overflow tank.

[nicklikesmilk]

not an expert, but i'd guess the water pump. has it ever been replaced?

[Billha]

If the coolant in the radiator isn't hot after the engine has been running long enough to reach operating temperature, then it sounds like either the thermostat is stuck closed or maybe there's a large internal coolant blockage somewhere in the engine or the radiator. I don't know offhand what could cause a large internal blockage in the engine, though.
Does the upper radiator hose get hot? If it does, then that would suggest that the thermostat is opening ok.
You recently replaced the thermostat, so that leaves the possibility of internal blockage, or although I've never heard of it happening before, maybe a defective water pump...but if the water pump isn't working, I would expect there to be other symptoms also, such as an odd noise.
It might be worthwhile to remove the belt to the water pump and turn the pulley by hand (while the engine is off and cool, of course) and listen to hear if it's moving coolant when you rotate the pulley. If it is moving coolant ok, then it seems there must be internal blockage somewhere.

Lastly, if the coolant is ending up in the overflow tank, then maybe there's a problem with the pressure relief valve in the radiator cap?

[trigga_b]

The radiator hose does get hot. I'll check the water pump tomorrow which has never been replaced. I tried to bleed the system, thinking there was air in the system, but I can't get the relief valve on the thermostat housing to budge. There's a pressure relief valve in the radiator cap?

So if it's an internal blockage I would have to get a engine flush or something? Or is there something cheaper to do?

Here's a pic thats show where the temp gauge is at all the time

[LeSabre in Buffalo]

Could the temperature sender be bad?

[93RedSled-SSE]

Are you familiar with drilling the thermostat to prevent an air pocket after replacing the the t'stat? You may have an air pocket at the t'stat, preventing warm coolant from contacting it and causing it to open/function.

I would recommend that (drilling). You can be sure that it is a t'stat problem (or air pocket) by running withOUT the thermostat installed to see if the problem goes away.

Here's a topic with some pictures of the drilled thermostat, etc.
http://www.pontiacbonnevilleclub.com/fo ... tat#p20648

[skregal]

Also when the car is hot, the radiator hoses should be stiff and hot. You can wear a glove and squeeze each radiator hose (upper and then lower). At the same time you are applying lots of pressure with your hand, rev the engine with the throttle. If you feel each hose collapse a little, or a significant pressure drop, then you know the coolant is flowing and flow is not the issue. If you have good flow then you can start to rule out bad water pump or clogged radiator. If flow is inconsistant then air pockets are the first thing to check if you changed the stat.

I had this problem but mine turned out to be my gauge. However, if you hear boiling and bubbling into the reservior, then you have heat issues.

[bill buttermore]

To eliminate air voids in the engine, try the coolant fill procedure described in Techinfo: Coolant Fill Procedure

Bubbling into the overflow tank and rapid overheating are symptoms of a blown head gasket. The problem with that diagnosis is, that head gaskets rarely fail on these 3800 engines. But, if you have tried the other fixes suggested, and the symptoms persist, take it to a shop and ask them to sniff the air over the coolant in the recovery tank with an exhaust analyzer. If exhaust gas is present, you have a blown head gasket. Do not assume that you have a blown head gasket without having the test done. It is very rare for them to fail.

[imidazol97]

Exhaust gas would be one thing to check for as already said. I wonder if there's wear on the impeller on the water pump so it's not effective at moving the coolant.

I note that the oil pressure is 100 pounds per square inch... That might be a result of a problem with gauges and voltage which someone else suggested. Did anyone else notice that high oil pressure reading?
I thought at about 60 the bypass valve in the oil pump opens to keep pressure around 60 maximum...

Is the coolant a 50/50 mixture so it has the required higher boiling point? Pure water will boil at 212 without a pressure cap.

Is your pressure cap building up pressure?

Is the little plate on the underside that seals to hold pressure but releases to allow the radiator to suck coolant back in from the reservoir clean and sealing? You should be able to feel the upper radiator hose tighten with the pressure as the motor nears operating temp. I had a car that would occasionally burp when heating up and coolant went back into the reservoir because that little plate didn't seal until water jetted through it because it had crud on it. Cleaned with toothbrush (an old one--not my regular one, grin).

The 50/50 coolant and the higher pressure should raise the boiling point to 230 or more.

Is the thermostat in correctly and is it opening?

[trigga_b]

I put the thermostat in a pot of boiling water with a thermometer and it turns out that it's in working condition. I tried to bleed the system from the housing valve, but it's stripped and won't budge, so I guess I'll be going o the junk yard to get another one.

I drove it around the block without a thermostat and it cooled a little better. The only thing is that the thermostat housing didn't create a tight seal to the manifold and coolant splashed every where. So I believe I have good pressure. Now I'm just waiting for the engine to cool down so I can use some gasket sealant and tighten the bolts.

[trigga_b]

Oh yeah, the oil reading is usually maxed out. So I probably need a oil pressure sender right?

[imidazol97]

I put the thermostat in a pot of boiling water with a thermometer and it turns out that it's in working condition. I tried to bleed the system from the housing valve, but it's stripped and won't budge, so I guess I'll be going o the junk yard to get another one.

I drove it around the block without a thermostat and it cooled a little better. The only thing is that the thermostat housing didn't create a tight seal to the manifold and coolant splashed every where. So I believe I have good pressure. Now I'm just waiting for the engine to cool down so I can use some gasket sealant and tighten the bolts.

Did you put the rubber o-ring gasket in without the thermostat. I'd think that would have sealed.

[trigga_b]

yeah I did, this never works out for me. I always have to use some gasket sealant. I even sanded the surfaces of the housing and manifold a little bit.

[imidazol97]

yeah I did, this never works out for me. I always have to use some gasket sealant. I even sanded the surfaces of the housing and manifold a little bit.

Did the thermostat fit into the groove in the middle of the rubber o-ring?

[trigga_b]

yea it did. just tested it without the thermostat in and it still overheats, but only to the 2nd line pass the 200 degree mark. So it's still overheating and I don't have any heat. Maybe it's the radiator itself.

[Pontiac1]

Sounds like the coolant system heas not been maintained well over the years.I had a similar issue with my 92 se.I ended up replacing the heater core and the radiator.I would try the link Mr.Buttermore provided for flushing the system,see what you get after that,then you will know more about how to proceed.Tim

[bill buttermore]

...I would try the link Mr.Buttermore provided for flushing the system...

Reverse Flush Cooling System

[trigga_b]

Ok thanks, I'll try the reverse flush and if it doesn't work, I will be forced to sell this car. My cousin hasn't paid a dime on it and I don't have the time to work on it anymore. I'll probably sell it around $700

[trigga_b]

These 12 hour shift are killing me. I haven't had time to do the reverse flush, but I got the tools and plan on doing it tomorrow. I touched the radiator after running the car and it was warm to me I guess since the temp outside was like 30 degree's. I touched the 1st radiator hose going to the water pump and it was cold.

I then touched the front of what looks like a radiator and it was cold like a socket wrench standing outside. What is this in the front of the radiator? Is it suppose to be cold right after driving an overheating car?

[bill buttermore]

That would be the condenser for the AC. You would expect it to be cold when the AC is not running. The radiator is behind the condenser, closer to the engine.