2001 Olds Aurora mystery coolant dissapearance

[laxmangl]

Heres the story:

My moms 01 Aurora has had a low coolant message on the DIC for months now, but the coolant was never low. We figured it was just the sensor, and since the sensor is built into the tank (I think) we just decided to monitor it and ignore the message.

A week ago when it started to get pretty cold around here in the mornings, my mom noticed her heat would only stay warm for a few minutes before blowing cold. We suspected heater core, but upon checking the coolant level it was pretty low, so we added some coolant and the heat is now fine.

Now we are wondering where the coolant went, its a closed system (I assume) and we can find no leaks. The oil is clean and my mom has never smelled anything burning.

Sooooo... any ideas?

[SSEi95]

I'm dealing with that as one of MANY issues with out '01 Aurora. Our coolant sensor will say low even after I top it off. However, we do have what appears to be a headgasket leak as well. We've noticed that it runs a little rough at startup sometimes (burning off leaked in coolant) as well as too much white smoke (like a fog) when the car first starts as well. Ours actually is at the point where it continually runs rough at idle from it now. I haven't dug into it yet since the front ball joints are shot, the tranny is almost dead, and the electrical goes AWOL form time to time. No need to fix a dying car like that :(

[94SilverSSEi]

Is it a V6 or V8?
Because the V8's are like the northstar and it could be a headgasket problem as I know they were fairly common In the Caddys

[00Beast]

It is a version of the Northstar V8, and yes it is a V8.

[laxmangl]

Well it runs smooth as glass according to my mom just as it should. It seems as though it wasn't a sudden loss as I first suspected. I will have her stand behind the car when she starts it to make sure there is no white smoke.

What are the symptoms of a shot head gasket, I feel like it would be pretty easy to tell.

We shall see how it goes.

[00Beast]

Blown Head Gasket: Burning coolant, running like crap, coolant in oil, hissing sound from motor, to name a few. If it runs good, and isn't using a lot of coolant I doubt it's a head gasket, yet.

[CMNTMXR57]

It's either the headgasket issue, OR a freeze plug issue. And chances are, because of Murphy, it's on the backside of the motor. It took me forever to find my leak. It only leaked when it was cold out. On a nice summer day, even on a cool engine, it never leaked.

The only way I found it was because a small droplet of coolant when the engine and exhaust were cool, as it dripped down into the exhaust crossover protection plate. Once the engine got hot, and subsequently the exhaust to full temps, it would simply burn it off (which was what I was smelling) and dry up, so when I'd try to find it after I ran the car, I could never find it.

My solution, went to NAPA, and got a can called "Block SEAL".

I fully drained my cooling system, then added the water and this block seal mix just as you would new coolant, and let it run for a half hour, flushing this block seal stuff throughout the engine. I then drained it and let it sit, with the cooling system open at both ends for over 24 hours.

Came back the next day, closed it all up, filled it with fresh Dexcool mix, and it's been fine since (I did it this past spring). Hasn't dropped anything and it's been pretty cool here for a month or so.

[1fatcat]

I have replaced countless water crossover gaskets and water pumps on these engines. The pump isn't too hard, the crossover gaskets are very hard.

Head gaskets are a common issue too with higher miles (120,000+).

[yourgrandma]

The V6 is a N* variant, too, FYI. Not a great motor, either.

[CincyGXP]

Have you tried GM's sealant tabs?

[cekmgreen]

hey guys thanks didnt realize this was from back in 09 i posted new thread

[repinS]

I split your previous posts into a new thread. Please continue here: http://www.pontiacbonnevilleclub.com/fo ... 17&t=29259