Slowly losing coolant?

[Stretch2126]

So I’ve had an issue with this for sometime even when the engine was in the cobalt. The plugs look fine, maybe on the leaner side but it will be tuned soon. The car still runs great and there’s no white smoke at all. The oil level is the same and it doesn’t look milky. I don’t see a leak and I don’t smell it anywhere on the car. Has anyone had it burp so much later or is it some kinda of head gasket leak? I would think the car would run rough or give some sign if it was.
The coolant reservoir drops about an inch after driving it for maybe 30 minutes. Or it did on the last trip.
Any ideas?

 

[Chubbs]

How old is your build?

The first time I drove the goblin, the coolant probably dropped at least an inch. The next time, it dropped a half an inch. By the 3rd or 4th test drive, all the bubbles worked out and it hasn't dropped since.

If this is your first drive, it's probably normal. If it's more than a couple drives old, it's got to be going somewhere.

 

[Stretch2126]

How old is your build?

The first time I drove the goblin, the coolant probably dropped at least an inch. The next time, it dropped a half an inch. By the 3rd or 4th test drive, all the bubbles worked out and it hasn't dropped since.

If this is your first drive, it's probably normal. If it's more than a couple drives old, it's got to be going somewhere.

Today was the second real drive. Like it got up to temperature and everything. Ran right at 189 degrees and drove great. I do have the LNF built on 11/08, but I would think a block would go way before 130k miles or show signs. I’ve also heard with the steel head gasket that it’s usually a big failure when it goes so I would see signs.

 

[Chubbs]

If it's only the second drive, I would drive it a little more before panicking. It's of course possible you have a problem, but I think it's too early to tell at this point.

And yes, I would suspect a head gasket would be more obvious. Fluid leaking, poor running, milky oil, etc.

If it persists, then start troubleshooting. My daily driver at one point exhibited the same symptoms (ran great, no visible leaks, no puddles, but coolant missing), and it turned out to be a slow leak from the radiator itself. it was high up, and by the time the fluid leaked out and flowed over the radiator on it's way to the ground, it either evaporated or blew away at highway speeds. It never left a puddle when parked. I just finally saw a crusty trail across the rear face of the radiator where the coolant was running down. It took a while to find it. Slow leaks can be tough.

 

[JBINTX]

Yes. It will take a few drives for both the coolant as well as the intercooler fluid levels to stabilize and get all the air out.
If nothing else is wrong....

 

[Rttoys]

I jacked with mine for about a month before it stabilized. Temps never got crazy, just the light coming on and having to add a bit. Then over fill and make a mess. And back to adding. And over filling. Adding overfill add

 

[cat5porting]

Vacuum bleeding really helps get the air out of the system.

You may also consider pressure testing the cooling system and pressure cap, as boiling off coolant is a potential result from a faulty cap.
Oil cooler is another common failure but I’d expect to see oil in the cooling system.