The Stovebolt Site Forums The Shop Area Engine Shop Leaking oil in my 1949 Chevy Truck

My oil is going somewhere and I cannot figure out where its going for sure. The engine does not smoke, so I don't think I'm burning it, and I have a catch pan in my garage, it isn't leaking very much at all. I'm losing about a quart in 300 miles. I was told it could be blowing out the vent pipe when I'm driving. Does this happen and what can I do? Is this normal? Can I get a new pipe? Thanks for your help!

yes you could be losing some via the crankcase vent, but replacing it won't change how much blow by you have ... what's 'normal' is for these old engines to be loose and get looser - check the compression

Bill

I can believe that Bill. I recently removed, wire brushed, degreased and primed the side and valve covers on my 216. New gaskets, meticulously clean mating surfaces, still weeps oil after a good run. I don't notice a change on the stick, but it's definitely "escaping".

http://i2.photobucket.com/albums/y7/pikappa167/fa053e3d.jpg

the covers are a whole different thing, they're notoriously hard to keep sealed and most long time bolt drivers will tell you these ol things just like to mark their territory - that pic shows a poor seal at the back of the rocker cover

but that wasn't your first question, if you have drips from the road draft tube on your parking space, it's indication that when you're on the road the road draft crankcase vent is putting out an oil mist mostly a result of blowby, and as I said, changeing the tube [or even cleaning the filter material in it] isn't going to stop any 'weeping' you see anywhere, and it won't have anything to do with oil seeping higher up unless it's totally plugged causing the engine interior to be pressurized .... if you're using a quart in 300 miles, where you'll find it is all along the roads you drove that 300 miles

check the shop manual about that tube

Bill

Hi, SiG, I had the same problem, turned out to be the new valve cover gasket shrank and leaked at the back of the cover, so I got a new gasket and used 3M weather strip glue and glued it to the valve cover and that stopped the leak.

Hello Sig,
I agree with the guys, in that if you aren't smoking you must be leaking. If the vent tube is the culprit and you drive highway speeds, it would seem you might have a nice oily coating at the very least, all under your truck... that's a lot of oil loss to me.
I think checking the gasket seal areas is a good idea, again you'd have oily areas from the source, down.
Curious... do you have a vacuum fuel pump? I've read that sometimes gas can get dumped into the crank case.
I'm asking... guys, could gas mixed with the lube make the lube go away? I'm not a guru... but I think in checking out everything, I'd check this too.
At least you're on top of it and not ignoring the problem. Hopefully you'll have this mystery solved and put your mind at ease.
Please keep us posted... this is something many could learn from.
Jerry

Hey guys thanks for the tips. I looked in my shop manual for details about the vent tube, I can't find anything on that. Anyone know where it tells about that. Thanks!

You can burn a quart in 300 miles without noticing smoke. If you look at your plugs and they look wet, you are burning oil. Also is there is a lot of buildup on the plugs, you could be burning oil. Leaking a quart in 300 miles would make quite a mess.