mystery oil leak

[johnboy914]

72 1.7 djet - There seems to be oil leaking from the intake manifold right where it mounts to the head. After highway driving there is a puddle of oil under the injectors. The head/manifold junction is the only place that I can guess that it is coming from. Anyone heard of this before? My guess is blow by. The motor had been sitting for about 20 years before I brought the car back to life. If it is blow by, is there a chance that the rings will seal up a bit with use? I did a compression test and at high altitude (7700ft)they are all at 115+-5lbs, which seems ok. Any thoughts are appreciated. Thanks

[John Rogers]

Rocker cover gaskets probably. They will come loose and the tops get pulled inside from the vacuum inside the engine at low RPMs and at high RPM will let oil blow out it it ends on that little ridge under the intake manifolds. My 2.8l does it and I am modifying a set of stock covers so this won't happen by MIG welding a strip of metal around the inside of the gasket area to hold the gasket in place. I'll take some picts and do an article for the site here when done. For the present use some good hi temp sealant, new gaskets and make sure the bale is tight. Good luck.

[Dave at Pelican Parts]

Another possibility is the hose going to the head vent. (If equipped; I've known some 72s with and some without.) This hose often gets exposed to a fair bit of oil and heat, so it tends to get brittle and crack and leak. Pull the hose off of the vent and see if it's still pliable. If not, cut off enough hose until you get to some that is. If you can't do that, then replace the hose.

Usually oil slopping out of the vent only happens during "spirited" driving.

--DD

[scotty914]

well two questions... one is it both sides or just one and if it is one check the oil pressure sender on top of the block
two check the heads for cracks going from the valve cover to the injector area, if it is you could be getting blow out from the heads



------------------
scott thacher
75 1.8 running at last
75 under rust
(fine german rust)

[johnboy914]

I replaced the oil pressure sensor, not that, and it is on both sides, equal amounts. I did check the breather hoses and they were the first source of the leak, and I replaced those, but now, this is just driving me nuts. I ran it again and got it up to temp and I can see tiny, tiny oil bubbles coming from the top of the nut that holds the intake to the head. Coming up through the threads. There is also some oil near the filler neck, so I am beginning to think that this is blow by. I had thought that you only got that in very low compression situations, like 80#&

[John Rogers]

It's the valve cover gaskets....I had the same thing happen and even pulled one of the carbs and manifold off at an auto-x as I thought the oil was coming out of the head some how? Unless you use a hi temp sealer and let the gaskets set and the bale is very tight there is a good chance the gasket will fall into the rocker area and at hi RPM you'll get oil blowing out. As a side note, I only get gaskets from one place, they lay them flat and they fit great as opposed to some shops that hang them on a nail and distort them.

[Jake Raby]

There is a bottom and top of the valve cover as well, they only go on "leakproof" with the VW logo upside down....

This is true, learned it the hard way....