Coolant Level keeps dropping, not a leak

[tzsonic]

As the title says the coolent level is dropping, and I don't know why, it's certainly not a leak. I've replaced the coolant reservoir and the return line already from a previous issue. Could it be the head gasket? A while back there was a SMALL amount of whiteish colored goop on the cap of the coolant tank, 1.8L 150K miles. Could also be oil cooler I am hearing. The rest of my car is in good shape, so I'm willing to do the head gasket and oil cooler if it extends the life of the car. Looking for input or advice, thanks

 

[Dingleberry69]

If oil is getting into the coolant, would hazard a guess it’s head gasket or oil cooler. Milkshake in the coolant reservoir is never a good sign. Also was there any sign of overheating over the history of the car or your ownership? If so, make sure, if you do the head gasket, that you get the head checked and make sure it’s perfectly flat. If it’s not, then it will leak in short order as the gasket will not seal as good in the high spots. I would still get it checked even if there weren’t any overheating incidents. Doesn’t look like a horrible job doing head gaskets, but it’s also seemingly one job I would not love too much to do twice.

 

[tzsonic]

If oil is getting into the coolant, would hazard a guess it’s head gasket or oil cooler. Milkshake in the coolant reservoir is never a good sign. Also was there any sign of overheating over the history of the car or your ownership? If so, make sure, if you do the head gasket, that you get the head checked and make sure it’s perfectly flat. If it’s not, then it will leak in short order as the gasket will not seal as good in the high spots. I would still get it checked even if there weren’t any overheating incidents. Doesn’t look like a horrible job doing head gaskets, but it’s also seemingly one job I would not love too much to do twice.

I have no knowledge of the car ever overheating during my ownership, as for past owners, who knows? I don't want to unload the parts cannon if it isn't necessary...

 

[Dingleberry69]

I have no knowledge of the car ever overheating during my ownership, as for past owners, who knows? I don't want to unload the parts cannon if it isn't necessary...

I really don’t blame you with not wanting to unload the parts cannon. Especially seeing how things are nowadays, could be a very expensive solution.

Did you perform a pressure test? If not, highly recommend that before proceeding further. A leak small enough could evaporate by hitting hot metal , block, exhaust etc. do a pressure test when the system is cold, and check for hoses with pinholes and any place where coolant is run. Might have a leaking hose or something and not realize. At least with the engine cold, you can really dig in there. If you have already done this and confirmed it was not a leak, then it would be time to continue with parts replacement (most likely culprits first, oil cooler, etc.