Mystery coolent leak ~ 2001 Tahoe

[Ramsair]

Hello all - interesting challenge, never seen this one before. 2001 Tahoe LT - 80K on the clock - maintained extremely well.

Issue: Last Saturday morning looked under my Tahoe and saw multiple coolent leaks. Upon further inspection I noticed drips all over the skid plate - looked higher and saw more from up on passengers side front of motor. Coolent level in overflow was not low. My wife said that the low coolent light came on a few days ago (failed to mention it, grrrrrr). I could not find the source - and looked everywhere - so I took it to a local shop and told them that I had a leak and to please find it. 3 hours later I get the call - they can not find the leak (mechanic owns a Tahoe and is bewildered). I went down and looked under the truck, as it was on a lift - nothing. Skid plate removed and pressure test was on up top for the last 2 hours with nothing leaking. Ran it hot, nothing. So I brought it home -

It has now been 5 more days of constant driving - driveway is clean - no leak, no drops, no nothing.

One thing I know for certain in this world - cars do NOT fix themselves. Any comment or insight would be greatly appreciated.

Chris

[WalrusInc]

Coolant quick coupler? Can't recall off the top if they had switched back to a fitting by then or not. I'm sure you've already checked this but it would be the right area.

[RainRider]

Ramsair,
Wonder if a bit of "foreign matter" worked up under the radiator cap seal, causing pressure/coolant release until it cleared the seal???
Just a thought. .. . If coolant recently added (via radiator cap), maybe sealing better now? But then, not sure whether recovery tank would catch it. I probably should go read about the radiator cap and recovery tank to see how that's supposed to work. After reading, see that coolant would have to get past the top cap seal.
Rain

[Ramsair]

Thanks for the thoughts - I will look at the coupler tomorrow and see if I can find anything.

The "burp" concept is one I have considered... as for the radiator cap, it appears to only be the cap on the overflow - as the radiator it self is contained and the coolent was definately on the front of the motor coming down.

No fluid has been added, nor did it need to be - even with low coolent light that my wife saw, but I have not.

Do you think it would be a good time to do a flush and refill? At 80K should I consider doing all my hoses? I do live in AZ and it has been in service since 09.01 --- and most importantly it sits outside ALL the time. Maybe I should just replace the cap on the overflow and call it a day.

Thoughts?

Thanks ~

[2000CAYukon]

If it has never been changed, then now is a good time since the coolant should be replaced every 5 Years or 150K Miles. Cap should be replaced every 2 - 3 years.

It would also be a good idea to get the system pressure tested in case there is a leak and it should be repaired before flushing and filling.

//2000CAYukon