Overheating Diagnostics - Continued...

[Mitch90535im]

Can you feel hot air being pumped by the fan when the car is running ? How old is the radiator on the car ? After you shut the car off how long does the cooling system hold pressure ? If the top hose collapses quickly I would guess that you have a leak somewhere. How does the engine oil look ? Does the car make steam a lot out the exhuast ?

Can you feel hot air being pumped by the fan when the car is running ? Which fan? Heater fan inside - yes. Main radiator fan - yes, but it doesn't appear to increase when hot (that's why I replaced the fan clutch to begin with, plus it spun a few turns, didn't come to an "abrupt" stop, when the engine is turned off hot) Aux radiator fan runs with A/C on. Temp still wanted to creep over 1/2 even with aux fan on.

How old is the radiator on the car? 2 months

After you shut the car off how long does the cooling system hold pressure ? Not sure, but it does seem to be pressurized when I remove the overflow tank cap, or open the bleed screw.

How does the engine oil look ? Good and clean

If the top hose collapses quickly I would guess that you have a leak somewhere. (Hard as a rock)

Does the car make steam a lot out the exhuast? It always has - no more than usual.

[George Davis]

"The odd thing is that this all started just after a coolant drain, flush, and fill. That's obviously why I suspected trapped air, but I've bled dozens of times, and there really doesn't appear to be any trapped air at this point."

Too much of a coincidence. I'd suggest bleeding again, with the engine hot so you're sure the t-stat is open. I think it's also a good idea to have the nose of the car higher than the tail, like on a slope or ramps, that way any air bubbles move (upward) toward the t-stat end of the engine.

There are probably some creative ways to test water pumps in place, but it will be messy. One way would be to pull off the heater supply hose from the block outlet, block the hose end, then install a length of hose from the block heater outlet and into the radiator fill hole so you don't lose all your coolant. (I'm guessing about the heater hose because I don't know how your engine is configured.) Start the engine and it should pump coolant out of the hose if it's pumping. If you only have access to the heater return hose, the same should work but run the extra hose from the heater outlet to the rad filler and block the heater return fitting on the block, and be sure your heater is full on. Alternatively, remove the pump and make sure it's definitely in one piece. If it isn't broken and the belt turns it, it's a pretty good bet it's pumping.

[JonE]

Can you feel hot air being pumped by the fan when the car is running ? Which fan? Heater fan inside - yes. Main radiator fan - yes, but it doesn't appear to increase when hot (that's why I replaced the fan clutch to begin with, plus it spun a few turns, didn't come to an "abrupt" stop, when the engine is turned off hot) Aux radiator fan runs with A/C on. Temp still wanted to creep over 1/2 even with aux fan on.

Are you sure that new clutch is good? Some people have reported getting a bad one. I could tell the difference right away when I changed mine, the sound was much louder as that fan started to really push the air around, kinda like a big truck, sorta like a "roaring" sound. Either that or there is something else not allowing that clutch to get hot enough to lock up. George Davis's suggestions sound good. I assume that it was bled properly with the heater on high while bleeding? T-stat is good and inserted properly? Hopefully others will have better advice for you, too.

[632 Regal]

blown head gasket??

I hate to say it but since this started right after you flushed and bled it quite coincidental. Just an option.

Back to basics here...T-stat, trapped air, water pump, radiator or clutch fan.

Elimination says rad is OK,

T-stat hasnt been replaced...replace that and the pump if it hasn't and go from there.

[Mitch90535im]

blown head gasket??

I hate to say it but since this started right after you flushed and bled it quite coincidental. Just an option.

Back to basics here...T-stat, trapped air, water pump, radiator or clutch fan.

Elimination says rad is OK,

T-stat hasnt been replaced...replace that and the pump if it hasn't and go from there.

What is about drain, flush, and fill that would lead you to think Head gasket?

[632 Regal]

overheated the **** outta it?

Doubt it thats whay I said back to basics.

[Mitch90535im]

I try to be really careful to avoid that. It scares me to drive it when it creeps barely past 1/2. I thought I might try jumping the fan switch plug to make it run on high, but since it still wanted to overheat with the aux fan running via the A/C switch, I really don't think that will make a difference.

My guess (and that's all I'm qualified to do at this point) is that either:

1) the thermostat is not opening fully
2) the water ppump is not moving coolant
3) trapped air
4) head gasket or crack
5) bad fan clutch from BMA? New one appears and feels just like the old one, which doesn't seem to increase air flow when increasing rpm's when hot, nor does it come to an "abrupt" stop when hot. Of course that all depends on the exact definition of "abrupt"? It spins by hand about the same, whether cold, or hot and to me that just doesn't sound right? Should I maybe talk to Patrick/Yeves about a return/replacement? Without seeing one on a car that we know is good, I just don't know how to gauge if this clutch is good or not.

The fact that the heater works, and blows warm air - does that indicate either that the water pump is ok or that the thermostat is ok? Or does it not really tell me anything?

Did I mention I'm a complete novice at this?

[632 Regal]

it should make a lot of noise, kinda like a schoolbus accelerating. When they are cold they will be tight as when they are warm so that isnt a test.

[Derek A.]

If the cooling system is not full of water then the radiator will not radiate warm air and it will not allow the viscous fluid in the clutch to lock up and pull the air. Can you see coolant squirting through the recovery tank on the firewall ?

[Mitch90535im]

"...it should make a lot of noise, kinda like a schoolbus accelerating"

It really doesn't seem to make any difference with it hot vs cold. Now I'm beginning to wonder if I received a bad clutch from BMA?