So I have a 2000 Oldsmobile Intrigue with about 190k miles. It currently has an overheating problem but first I’ll discuss some history:
-It had a previous overheating problem a few months ago that was accompanied by bubbling sounds. We diagnosed this as boiling coolant because the system was not pressurizing due to a leak in the reservoir. We fixed the reservoir leak and pressure tested it to find that the leak was repaired. The bubbling noises stopped and the car no longer overheated.
-The car was then underheating nearly all the time. We diagnosed this as a broken thermostat, probably killed by the overheating that was caused by the leak in the reservoir. We replaced the thermostat and bled/burped the system and now the car does not underheat.
Now the car operates around the half-temp mark and stays very regular except in traffic or parked in the driveway. So it overheats when it is idling. You can rev up the engine in these cases and see the temp gauge fall back down, so it is dependent on RPM only and not on the actual traveling speed of the car. Also at this time the car supplies nice heat to the cabin.
Things to exclude:
The electric fans seem to be working fine and they switch on and off supplying a good deal of wind.
The system was bled/burped.
The system has a new thermostat.
The system does not leak based on a pressure test.
The system has enough coolant.
The system supplies good heat to the cabin.
My guess is that there is a clog/general grossness inside the system someplace or that the water pump is starting to fail, what do you think?
So when it is overheating in traffic, the radiator fan is coming on full force? And even with the fan on, it still overheats then?
I guess if I had this problem, I’d suspect an air leak somewhere, the radiator or resevoir cap, hose, gasket, etc. It’s possible for a mechanic to pressure test the cooling system to see if it is holding pressure correctly, that might be a good idea. It could be the water pump is just not pumping enough water, or the radiator is clogged up. A radiator shop could probably test the radiator for you, and declog it if necessary. And there’s a chance the head gasket is starting to fail. A mechanic can do a chemical test for exhaust gas in the coolant to rule this out or in. If everything turns out negative, then replacing the water pump might be the next thing to try. Make sure the water pump belt is in good shape and tensioned properly of course first. A slipping belt could cause this symptom.
@GeorgeSanJose I already pressure tested the system myself and I used it to diagnose a leak a few months ago which I repaired. It now holds pressure all day. So a clogged radiator can be declogged and doesn’t necessarily have to be replaced? By water pump belt do you mean the serpentine belt?
Since there is only the cap on the reservoir, there is a small (1/4") line that goes from the top of the reservoir to the radiator hose inlet on the opposite side of the engine. This is a self bleeding system, but if that line gets clogged up, you cannot bleed the system. Make sure it is clear end to end.
BTW, Dexcool was formulated to reduce erosion on the impeller blades of the water pump. If someone has used another type of antifreeze that contained borates and silicates, then erosion could be a problem. Modern long life antifreezes have eliminated those compounds so it is no longer necessary to use Dexcool, you can use any universal long life antifreeze, but I’d recommend sticking to a major brand though.
We have GM and Ford vehicles in our fleet. And the ones that look like the one in the picture are almost always the ones that NEVER had the coolant serviced.
That thread is 5 years old, by the way. And the car in question was 3 years old at the time.
I suspect that the DexCool formulation has changed since then, no matter what GM may say.
I guarantee you there are no 3 year old GM vehicles in our fleet that have Dexcool that degraded.
Deathcool is still an OAT antifreeze and not a HOAT antifreeze to this day. So the formulation hasn’t changed.
What difference does it make when the article was writen? That’s still a three old vehicle serviced by the dealer and the problem still occured.
Everyone I know is aware of the Deathcool problems. And those who buy new GM vehicles have me replace the Deathcool in their vehicles as soon as the vehicle goes out of warranty.
Yes @KRA2008, a clogged radiator can be declogged by your local radiator repair shop. Look in the yellow pages. On an econobox, it probably makes more sense to just buy a new aftermarket radiator. Econobox cars – esp those w/manual xmissions – have modest cooling requirements.
But on bigger cars with higher power engines, with auto xmissions, air condtioning, etc, they have greater cooling requirements, and the OEM radiator that came with the car is probably better than any aftermarket version you could buy, so declogging the original is usually the preferred method. I’m not familiar with your car. Does your car require higher than 87 octane fuel? Does it have A/C? Does it have an auto xmission? If so, that would be an indication the radiator declog method might be better for you.
By water pump belt, I mean whatever belt drives the water pump. The water pump is powered by various methods, depends on the car.
KRA2008, my sympathies to you. I had a 2001 Intrigue with only 95K miles on it when it started developing this problem 2 years ago, running hot and losing coolant. Systematically, and one at a time I had all radiator/cooling system parts replaced starting with the obvious and easiest to replace items (spending about 4K total). The head gaskets were replaced several times (as another person here suggested on my post last summer) as when it runs hot these are compromised. Even after all of this effort, the car continued to have this problem that worsened over time. At the end, I had to add 1.5 gallons of coolant (just water at this point) every day before driving and the car’s range before overheating got progressively shorter. Recently, I sold the car for parts (the exterior and interior were in great shape) and when the 3.5 liter engine was removed and disassembled most of the inner block coolant channels were corroded and clogging. The mechanic was familiar with this problem and would have recommended having a rebuilt engine installed instead of all the work I did. If this description matches your problem, you may want to cut your losses now.
why is my 2000 oldsmobile intrigue still overheating ive replaced the waterpump and thermostat with aftermarket parts from autozone i have replaced the surge tank with one i pulled from the junk yard. there is no oil in my water or vice-versa there seems to be a small leak coming from coolant crossover pipe wich im dreading fixing… any sugestions on to why my car still over heating?
So I flushed out the whole system really well with hose water and plugged both ends of the radiator with it full of CLR. Then I rinsed all that out and gave it all new coolant. I also went ahead and replaced the reservoir tank that I mentioned having repaired the leak on because it turned out the repair wasn’t holding. I also went ahead and replaced the cap. I also noticed the coolant level sensor on the old tank was probably shot. Now everything is nice. Total cost $75.
In MI: I have a 1999 model with same engine…same symptoms…problems …etc. But here is a twist for ya…In the Summer when it is 60-105’F… the car runs perfectly fine…cool air …no problems. The car Temp stays at a steady 50% mark.
But, as soon as the air ambient drops below 55’…it heats up and has issues!?? It can be the dead of winter…10’F…and this thing gets hot! Today it was down to 35’ am…high of 45’F today…it ran hot at 75-85% mark most of the day.