Head Gasket Help...

So I purchased a used 2011 Limited a few months ago. 244K freeway miles. Good service history at dealer. Had a mechanic friend come look it over with me. Saw no issues other than a couple of minor oil leaks. Runs, drives perfect. Idles perfect. Checked code history-nothing. Does not overheat. Changed all the fluids when I bought it-all oil and drain and filled coolant. Replaced thermostat with oem. Nothing was wrong with it, just figured why not. What I noticed is it appears to be losing coolant. Seems to lose about 1/4"-1/2" on the overflow tank per 200 miles or so.

-No external leaks-verified by me and mechanic.
-Chemical block test performed by me and local reputable shop-negative for combustion gasses in coolant.
-Pressure test cold-Set to 15psi, drops to 14psi or so and holds for 20 minutes.
-Put 14-15psi pressure into cooling system while cold for 2 hours. Pulled plugs and looked for coolant via borescope. Couldn't see anything. All cylinders looks similar-carbon build up, slight oil leak from valves seals. Would I not expect to see one clean cylinder if the head gasket was leaking?

No big clouds of smoke on start up. I do get some vapor/oil smoke? on cold start-from what I have read, some say normal amount, some say too much. This video
https://youtu.be/mLhf0Zpe25o
is from this morning. 65f, 90% humidity. I am revving it a bit right after start to about 3,000-3,500rpm.


I have an appointment for a leak down test this week. Not sure how to definitely find out whether the gasket is blown beyond that test. Any input is welcome and appreciated.

 

Nothing concerning in my honest opinion.

 

Thanks.

 

Based off of the results of all of the tests you performed, You appear good.

 

I am hoping. Just not sure where it went/going.

 

Took it to another shop recommended on here. Same thing-couldn't find anything. Left it pressurized all night, borescoped cylinders in the morning, nothing. Nothing in intake manifold, coolant bypass hose at throttle body, throttle body, nothing. Pressure did drop from 15lbs to 7psi overnight. They were not sure if that was from test equipment not holding pressure, but either way it didn't yield any results.

 

Just curious, what part of the country are you in?

- I once saw this issue because a Jetta heater core was weeping.

-Once had a rear coolant flange that weeped on an A4, common issue because the plastic would walk over time from heat cycles and it was a milled flat mating surface.

- porous m96 block in a 03’ 996, never showed up.

there’s a lot of little ways for things to happen, especially to machines with a little age on them. Best advice is think of it like a wrestling match. Stay calm, think methodically, observe the opponent (in this case, the phantom leak) and note and conditions or events that cause change.

above all else, keep us in the loop.

$.02

 

Socal. Thanks. Will do.

Hooked up the vacuum pump again cold. Lost 1psi in 2 hours. 15psi to 14psi. I think this is the limitation of the pump to be honest-Mityvac MV4560-as I hooked up my wife's Corolla for an hour and it lost 1psi also.