Where does the coolant go??

[alpac]

3 weeks ago I got the 'Check Coolant' message. I checked it out and it was indeed very low. I added some coolant up to the top limit. Today I checked it again and the coolant is at the lowest limit. Where does this coolant go?? I cannot see any leak anywhere. The entire cooling system (radiator, water pump, hoses, etc...) was replaced 16 months ago. Very strange

[ifly]

Its those damn pesky molecules that escape through molecule sized holes!

Thats my theory anyway without looking at your cooling system.

[rayxi]

I asked the dealer service rep the same question. Sometimes it's because of an air pocket that didn't get bled off during a coolant change and has eventually worked itself out of the system. Other times it's a mystery.

Top it up and check again in a week. If it goes down again take it in to the dealer.

[gregwx5]

it might collect in the plastic underbody engine cover..and leak out when you start driving at higher speeds? just an idea!

[fast4d]

remove the plastic top cover and look down into the top of the valley. if you see moisture then it's the valley cover. that's if you have a V8

[JV]

Originally Posted by fast4d

remove the plastic top cover and look down into the top of the valley. if you see moisture then it's the valley cover. that's if you have a V8

I was gonna say this too. Rob_ had a good post with pics on a replacement he did on a 740 (4.4L engine) last year.

[alpac]

Thanks

[viperdark]

so if its a 3.0 its probably not the valley pan gasket?

[cocoabrova]

Originally Posted by viperdark

so if its a 3.0 its probably not the valley pan gasket?

Might be a hose leak or headgasket leak (the I-6's HG's are known to fail, but ususally not bad enough to warrant a HG job i.e. a small drip from the rear corner of the HG). On my 4.4, I'm going to have my valley pan gasket done as well as the pan/cover too, due to a small coolant leak that ends up dripping from the rubber plug on the tranny. Also since the intake manifold has to come off, I'm going to get the cyclone valve and and all pertaining hoses and such replaced.

[flatlander]

I had this mysterious coolant leak also. I seemed to be losing coolant every two weeks. I'd top off the reservoir expansion tank, bleed the air out, drive for hundreds of miles without sign of a leak. Then the low coolant alarm would go off. finally, I had a major sign of leakage from the back side of the engine: coolant was dripping down right at the back of the lower engine cover. I took it to the dealer assuming this was the valley pan gasket problem or the rear cover gasket. The dealer pressure tested the coolant system and found nothing. They say it has no leaks? What gives?

Is this consistent with the rest of you who've had the valley pan gasket problem?