Took the valve cover off to replace the gasket the other day and noticed there was a lot of sludge caked on and clogging the breather vent. Took some degreaser to it and a tooth brush but couldn't really get it as clean as I had hoped. Now I have a leak coming out from the oil fill cap, was wondering if that could be from the breather being clogged and if anyone has any better ideas on how to get all the crud out of the vent. Also does anyone know if you can just pull the rubber grommet out from the top of the valve cover without destroying it, so i can get in there a little better.
Too much pressure in the engine can force oil out past the fill cap, but unless you made the clogged screen worse than it was it should not happen. That rubber grommet does just pull out but it is for sure old and hard so expect it to break if you try removing it. Those vents are hard to clean by hand, best is to soak it in some good de-greaser or use a parts cleaning tank if possible. For all the effort it could be cheaper time and material wise to just find a good used one to swap out.
I think I have the same issue. I noticed there was oil coming from around the oil filler connection, so I bought a new gasket/seal for that. That worked very well, but then after a week or so, the rocker cover gasket started leaking out of nowhere. It really seems as though I blocked one escape for the oil, so it found another one.
While I have the rocker cover/calve cover off to replace the gasket, I'll see if I can clean out the oil breather, maybe I'll just buy a replacement if it's cheap enough, and put it straight in while I have everything apart anyway.
The breather is clogged. Also if your valves or rings are worn you will get blow by. Put a bigger breather on it or use a catch can. I just had this issue. I started a thread about it in the mk1 forum not to long ago.
. . . but then after a week or so, the rocker cover gasket started leaking out of nowhere. It really seems as though I blocked one escape for the oil, . . .
Spend the extra few bucks for the rubber gasket. It fixes one of the common leak spots, where the cork gasket meets the rubber part that goes over the end of the camshaft. It is also nice because you can remove it and use it again and again if you want/need to. And yes, if the screen is so clogged that no air/vapor can pass through then the oil will seep out other places. I found that stuffing some course steelwool into the hose seperates the vapor and keeps most of it from reaching the air filter box.
Originally Posted by Jesse-B
Also if your valves or rings are worn you will get blow by. Put a bigger breather on it or use a catch can.
Blow-by is over rated, over discussed and often blamed for lack of a better answer/reason. I have never seen or heard or read about an engine with so much pressure built up in the crankcase that it would cause oil to be forced out without either the engine running like poop or the seals being old and dried up. It is 100% normal to have some crankcase pressure as the rings never seal completely, even total seal or brand new broken in rings. I have worked on engines that smoked like a factory due to worn rings that did not have crankcase pressure so high it forced oil out any seals. Burning way to much oil is a side effect of bad rings, all engines burn some, a slight loss of power due to the oil in the cumbustion chamber also, but "high" crankcase pressures just don't really happen just due to bad rings.
I don't know how you would put a bigger breather on it unless you modify the engine somehow to mount one, like a hole in the valve cover, but that's a wasted effort really. The original system works just fine if kept in good condition and there is no reason for adding any open air breather to it, that's just old High School parking lot stuff. Catch cans are fine for racing or to install within the original system if you rather do that then fix the real problem, but room is often an issue and the problem is not pressure but rather just vapor. Oh, valves have nothing to do with blow-by. Yes if the valves do not seal for some reason the combustion gasses can "blow by" the valves, but that has nothing to do with the crankcase.
The new valve cover breathes very well compared to the old one and isn't forcing oil out of the fill cap anymore. It definitely leaks less oil but I thought that it would have eliminated the couple drips of oil that I kept on finding under the car, but I think oil is slowly leaking out of somewhere else. Almost looks like the oil pan gasket or the rear main seal... not too sure. When I peer under the car there is a little drip coming off of the tranny right next to the oil pan. Any ideas?
Clean the bottom of the engine with some engine cleaner. And then start the car and run it till it warms up. Then you should be able to find the leak. I had the same problem. Going to change out the oil pan gasket out myself this weekend.