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2008 A6 4.2 - Help me figure out where the vapor is coming from
I have bene trying to figure out this weird coolant leak for a few months now.
2008 A6 4.2. Original coolant hoses, water pump, thermostat.
While warming up (seems to be until the thermostat opens up), I will get this cloud of vapor that sure seems to be coolant.
The coolant level will drop gradually over a fe weeks until I need to refill the reservoir.
I did a pressure test and it held pressure for an hour. Dropped slightly, but not significantly.
The vapor is coming from the drivers side, mid engine. I have looked through diagrams and don't see any coolant related things there.
I don't see anything from below (e.g. obvious vapor from around the thermostat).
I have a video from above and below. Before I take a bunch of stuff off to see what is in the area, I was hoping someone might have an idea of what this could be.
After thinking about it, I agree it is not coolant. There is a cam sensor right there too. I replaced the valve cover gaskets a few years ago. Going to start there today. Take the valve cover off and check that cam sensor. I have a smoke machine too so going to fire that up before anything else.
To quote Spalding Smails - "Rat Farts".
Took the valve cover off, cleaned everything. Took out the cam sensor there and cleaned everything.
Valve cover gasket was replaced a few years ago and is still pretty pliable.
It also seems like I would be losing oil, but it reads right in the middle on the dip stick.
It is definitely not coolant, but I don't know how to change the thread title.
No difference. I even noticed it is doing the same thing on the passenger side too. I looked from underneath and it looks like some oil is pooled on the underside of the exhaust manifold. It is so tight in there, it's hard to see anything.
There is a lot more room on the passengers side so going to remove the air box and have a better look on that side tomorrow.
There is definitely an oil leak somewhere. Just seems odd to have this at about the same place on each side. Going to get some kind of mirror on a stick (I'm sure Harbor Freight has something) and use that too.
The vapor started almost instantly which tells me there is oil pooled there. I may also try removing the the belly pan again and flushing some water through the area to clean it out.
The coolant overflow tank was replaced a few years ago. I have figured out it is not coolant. I did a coolant system pressure test first and it held pressure with no problems. I do seem to slowly lose coolant, but that looks like a different issue.
I replaced all 4 of the cam solenoid o-rings a year or so ago. I did two smoke tests and all I found was a small leak on the drivers side intake cam solenoid.
I checked spark plug wells today when I removed the valve cover gasket. No oil there. Hasn't been a problem since I changed the valve cover gaskets ~4 years ago.
I am not getting any codes for misbehaving PVC. I replaced the purge vale ~2 years ago and have not had a problem since then.
I replaced the oil filter housing gasket ~ 1 year ago when I did a carbon clean and fuel injector clean. Any oil leaks from the top will run down the valley and out the front.
Hopefully the mirror(s) from Harbor Freight will let me see more on what i going on in there.
Last resort may be to remove the front end again so I can get a better look at what is happening on the exhaust manifold.
These are two pics I forgot to add the post with the 2nd video.
And the biggest problem is that I need to pass emissions to get it reregistered. I took it to one place and they shut down the test as soon as they saw the smoke (hard ot blame them for that). Whatever this is, it's causing weird readings at the rapid pass stations too. Those get setup on various roads and will read emisisons and you can check online. This time it i giving me some cryptic result saying the vehicle cannot be tested. Son of bitch.
I got back to it today. Took out the air box and started it up. I immediately saw that there was a ton of grime and oily mess on the coolant pipes and along the bottom of the valve cover area. Started smoking pretty badly so I stopped it. Removed the valve cover and cleaned everything. The valve cover gasket was not brittle but is definitely not pliable. I was mistaken, I replaced both valve cover gaskets in Feb. of 2019 60k miles ago. Guess it's time again. Ordered replacements already. I cleaned everything up as best I could. Started it back up and it was still smoking. Went for a drive to let everything burn off. When I got back, I let it idle for a while and no more smoke. Going to test it again tonight. I suspect the valve cover gaskets were seeping. As the engine cooled off, the crud would build up and drip.
01-25-2024, 05:51 PM
2008 A6 4.2 - Help me figure out where the vapor is coming from
