1996 Cutlass Supreme 3100 (M) overheating

[ragrone]

I have changed the thermostat twice, flushed the entire cooling system twice, and replaced the radiator cap and water pump. While traveling uphill at any speed/load, the temperature rises very rapidly. This has been verified using DIS the water temperature reaches 220+ F.

Traveling downhill; the temp never exceeds 185 (180 tstat installed now). Occasionally in traffic the temperature actually reaches ambient (195 - I would be happy with this constantly) however, most of the time the temperature “swings” like an old fuel tank gauge (needle floating all over the place with change in the pitch of the road).

The intake manifold gaskets changed only 70k on motor.

With the heater set on high and blower running, generally keeps engine out of the red.

I'm without a doubt going to need to change the radiator and heater core for with these kinds of pressure something has got to give (I can see fins "popping out" already).

What is wrong with this thing? No significant to any loss of antifreeze is noticeable. Is now running Prestone Dexcool "Orange"

[GTP Dad]

Two things to check, make sure that the fans are working. If they are make sure you got all the air out of the cooling system. A small amount of air in the system will cause the water pump not to work properly. I believe that you will find that you have a cooling fan problem.

[ragrone]

Originally Posted by GTP Dad

Two things to check, make sure that the fans are working. If they are make sure you got all the air out of the cooling system. A small amount of air in the system will cause the water pump not to work properly. I believe that you will find that you have a cooling fan problem.

nope both fans are operating as normally would turn on at 210

[GTP Dad]

If that is the case then check the system for air.

[ragrone]

was bled both times and have checked same repeatedly..... no air in system, fans working, no "apparent" or significant coolant loss

[GTP Dad]

Did you change the water temp sensor? It may have gone bad and is giving bad readings. Also the only other thing I can think of that would cause this many problems would be a bad water pump or a partially blocked radiator. Even though the system was flushed the radiator could have a blockage. Also, how old is the pressure cap?

[ragrone]

Originally Posted by GTP Dad

Did you change the water temp sensor? It may have gone bad and is giving bad readings. Also the only other thing I can think of that would cause this many problems would be a bad water pump or a partially blocked radiator. Even though the system was flushed the radiator could have a blockage. Also, how old is the pressure cap?

Yes sending sensor changed first item replaced, water pump changed, have bought a new radiator and heater core although, i was just looking at the heater core via the engine compartment and the replacement core i rcv'd appears to have different sized metal tubing to the the engine compartment

[GTP Dad]

Have you put new hoses on this car recently. Sometimes the hoses go bad internally and could be collapsing while the engine is running restricting water flow. Just a thought!

[ragrone]

Originally Posted by GTP Dad

Have you put new hoses on this car recently. Sometimes the hoses go bad internally and could be collapsing while the engine is running restricting water flow. Just a thought!

All the typical has been done kinda why I posted I thought maybe something I missed.

Dropped the car off at the dealer from whom I purchased, he called it looks like a head gasket problem in turn (which were my thoughts exactly) the pressure in turn has damage the heater core. If anyone has ever seen one of these "jewels" it's easy to understand (since the hose to the core itself are nothing more then being held together by a "c" clip and an o-ring to prevent seepage).

Thanks, I'll post the findings once repaired for future reference.

[ragrone]

Originally Posted by ragrone

All the typical has been done kinda why I posted I thought maybe something I missed.

Dropped the car off at the dealer from whom I purchased, he called it looks like a head gasket problem in turn (which were my thoughts exactly) the pressure in turn has damage the heater core. If anyone has ever seen one of these "jewels" it's easy to understand (since the hose to the core itself are nothing more then being held together by a "c" clip and an o-ring to prevent seepage).

Thanks, I'll post the findings once repaired for future reference.

Okay, here it is..... there may in fact be a minor head gasket leak but hard to spot) however, the air deflector is missing

[Scottoldboy]

Originally Posted by ragrone

Okay, here it is..... there may in fact be a minor head gasket leak but hard to spot) however, the air deflector is missing

I have a 95 Ciera 3.1L vin M, exact same story! I've changed the thermostat, then the water pump at 100k miles. Installed a HD radiator from Rockauto.com, twice as thick. No change. Saying the gauge swings like an old gas gauge is exactly right. As soon as I go up any hill the gauge zooms up to the bottom of the red. On a long hill the OVERHEAT light has come on and I stop and let it idle for several minutes and the temp returns to normal. Running the heater on high helps a little. No sign of water in the oil. No white exhaust. The coolant doesn't seem to disappear. I've bled the coolant at the two bleeders. The primary fan comes on when the temp is at the 3/4 mark. I talked to a GM service manager today and he says it's the intake manifold gasket that is allowing coolant into the cylinders. It doesn't jive with what I see going on. I don't seem to lose coolant. He says at 130k the intake gasket should have been changed long ago. Says he's never seen a head problem on this engine cause overheating. UPDATE I changed the temp sensor, the one on the back corner of the head. The temperature gauge is acting more normal now. The engine never did seem to be hot when the gauge said it was over heated. An over heated engine smells hot, smokes, and doesn't run right. This never happened.

[ragrone]

Okay to sum this up for you - and by the way my gauge still does fluctuate slightly still - having replaced the thermostat with a 180 degree one, replaced the air dam that was damaged, and repeatedly flushed the engine my problem has gotten much better.

While flushing the "engine" I kept noticing what looked like clumps of sand coming out. Not knowing at the time what this was (I found out while purchasing parts at the GM dealer. I was at the parts counter and noticed this packet with approx. 6 rather large "pellets" in them, that had the same color and consistency as what was coming out of the engine block) I asked the parts clerk what that was he stated "oh yeah that's great stuff, stops all kinds of leaks in the radiator and engine block. We use the ENTIRE, yes-ENTIRE freaking package. Well this package if used as directed states only use 2 that's right TWO of the damn pellets not the whole package, grind them up completely (not just breaking them into pieces, they look like rat cookies "poison").

What I did was as follows:

Removed the thermostat, drain the engine, run a good 10 minute flush threw it, (only a 10 minute flush for I was in fear of overheating), flushed and flushed and flushed until I was just plain sick and tired of running water through the damn thing. Next, I got a bottle of Barsdahl Block/Radiator sealant. Follow the instructions completely, this stuff needs to air-dry overnight at least to work properly, refilled it with Prestone Orange and then added a bottle of Barsdahl (Bars Leak) system conditioner.

Now, I was still a little leery, went to Advance Auto, and purchased a thermal “relay” fan unit. This device has the thermometer that lies across the top of the radiator. I purchased two more 30-amp single pole double throw relays. I created a “black-box” that monitors the temperature at the radiator and starts BOTH fans if the temperature at the radiator exceeds 200 degrees. This now guarantees that the water in the radiator always remains below the 180-degree level set by my thermostat. Currently I’m running about 174 degrees and occasionally under load the temperature will rise to 184 degrees, (the fans monitoring the radiator can be adjusted for start-up temperature), by the time this happens the radiator temperature has already climbed above MY settings and have cooled off the radiator fluid sufficiently enough that once it enters the engine it is BELOW the 180-degree thermostat.

Okay to sum this up – check your air dam, get the crud out of the engine, (and make certain it’s all out I mean run the dam hose right into the engine) with the thermostat removed, water pump off, and that the tubing that goes to the heater core is free of obstruction. The addition of the external temperature monitor now allows the fans to kick on and off while the car has stopped with the engine off, kinda like the way they should.

Do I still have slight temperature fluctuations? Yes, however now normally with the lower thermostat in the engine, the temperature gauge normally does not go above the first “warm-up” line (normal operating temperature area) but, the temperature does still seem to want to increase while the car is traveling uphill (very strange), it could be 20 below zero outside and it still behaves that way.
Bottom line – the dealer, some dealers’ mechanics cannot read (I know that everyone in this area was doing it) and using an entire box of that stop-leak that has the consistency of cement (it looks like sandstone). Was it or is it the Block stop leak, flushing, lower thermostat I doubt it, it was just plain clogged and these little “pellets” have a tendency to “erode” in to nice marble sized chunks that like to wedge themselves inside the cooling channels of the engine. Sort of rolling around in there.

Conclusion – sorry for being so wordy – ALL AUTOMOBILE MANUFACTURERS USE SOME FORM OF STOP LEAK IN EVEN THEIR BRAND NEW ENGINES. This is due to the fact the engines must run hotter to meet emission and fuel economy standards, and do IN FACT develop microscopic leaks in ALL of these gaskets/mating surfaces, due to the extreme temperatures, period, no arguments. I don’t care who anyone is that reads this, or who they work for, if they deny the above statement tell them to leave their hands off your car and take it someone that knows what the hell is going on.

If you would like a schematic of the external temperature control system I installed send me an email.

By the way, FelPro is now making replacement gaskets for this crap GM installs, use FelPro.

[Transistor]

I know this is a little late to answer this question, but I do have a answer that is unique through my own experience with this vehicle a 96 cutlass supreme.

It is very easy to install the fan belt so that it goes under and around the water pump pulley instead of over it. The distance for the belt is almost identical so the belt still tightens. The only problem is the water pump turns backwards and puts out much less water and has very little suction. It is trying to draw the water from the motor and push it into the radiator. Since the hose it is drawing water from is higher on the radiator, if the radiator is only a little low it will not circulate any water at all.

Do not laugh, I have seen it done. Hard to see and detect.

[maxwedge]

Please do not resurrect old threads, this is almost 3 years old! Thanks.