2002 Monte Carlo Losing Coolant!

[bassadict69]

I know this is a truck forum but I need a little help with my wifes Monte SS.

 

It is a 2002 Monte Carlo SS with about 90000 miles. The car is losing coolant somewhere & I cannot find it! Every 3 months or so, the low coolant light comes on & sure enough...it is low again.

 

I have been all under it the best I can with it being so low. I have put cardboard under it & let it run for over an hour so I could look for leaks on the cardboard. NOTHING! No coolant in oil at oil change...no wet floorboard...I can't find anything!

 

Help me out guys! Anyone know anything about these cars? What can I check!?

[jnpaddison]

does the over-flow tank level changing atall ??

does the temp guage climb into the red ( overheat ) ??

 

just wondering if the system runs hot - purges itself into the overflow tank - ( OFT ) overflows and at cool down cant syphon back the coolant ...

 

just an idea ...

[bassadict69]

does the over-flow tank level changing atall ??

does the temp guage climb into the red ( overheat ) ??

 

just wondering if the system runs hot - purges itself into the overflow tank - ( OFT ) overflows and at cool down cant syphon back the coolant ...

 

just an idea ...

 

The overflow tank level does change but it empties itself into the radiator when it gets low.

 

Car does not run hot at all...never has so far. It has never gotten above where it normally does, even after the low coolant light comes on.

[jnpaddison]

white smoke out of the exhaust pipe ??

[bassadict69]

No, no visible problems at all...no performance problems or issues with the way it runs either.

[jnpaddison]

Enigine Gnomes ??

[cm5]

check water pump and surrounding area. might be a slow leak from the wpump.

sometimes with a slow leak it will evapaorte before dripping on anything...

[PunchT37]

Might want to remove the upper plenum and check for cracks. It`s the plastic upper manifold, if you will. Look on the underside close to the throttle body. There are small holes there for EGR purposes and a lot of heat. Iv`e seen more than a few cracked and can cause all sorts of problems.

[bassadict69]

Thanks guys...I will check out everything suggested

[bassadict69]

I have been all over the car best I could & found nothing! Yesterday, I removed that upper cover & drove the car to warm it up but found nothing! Burned my dang hand trying to feel under the water pump for a small leak but found nothing! They sure don't leave any extra room on this darn cars engine compartment!

 

I think Wednesday, we will take it down for a pressure test!