TTop Tony

My car seems to eat oil at somewhere around 1/2 a quart per 200 to 300 miles. My odometer doesn't work so I'm just guestimating the mileage. I only see a few drops of oil on the garage floor so I can't figure out where the oil is going. Any hints on where to start looking? There's sometimes a blue puff of smoke when I start the car but after that the exhaust is clean. I'm a newbie with engines so I'm not quite sure where to start. Any advice is appreciated.

Monkeywrench

I had an older V6 chevy that had leaky valve cover gaskets. The oil would leak fom here but would burn off slowly as it dripped onto the exhaust manifold so I never saw the leak on the floor. Just a hunch. Check those gaskets...

Sean

79MakoL82

Blue puff indicates valve stem seals. This can be a source of oil loss, but usually not the kind you are speaking of. In terms of the oil on the floor, try to locate where the oil is coming from. Is it the oil pan or might it be coming from the valve covers. Whichever one, replace the gasket.


[Modified by 79MakoL82, 8:22 AM 11/26/2001]

TTop Tony

Am I supposed to put gasket sealer on these? I didn't when I swapped out my intake. Definitly some things to look at. I would have thought I'd see more dripping on the floor. Its my first sports car so I'm still learning

MikeC

I'd say your rings are gone. I'm dealing with this same problem in my truck right now. I replaced the valve stem seals earlier this year, helped a bit but when doing the seals, you could here the compressed air leaking into my crankcase. I'd suggest getting a leakdown test done on your engine.

john's '81 mouse

Tony, when installing cork valve cover gaskets, apply sealer / sealant to valve cover side only, and don't over torque the bolts. Make sure the valve cover lips are straight, and not bent / warped from past over tightening. If you have the steel valve covers, which stock L-48s did have, suggest you use the bigger / after market longer steel brackets to prevent bending the valve cover lips when snugging them down.

Your oil consumption problem really sounds like valve stem seals are bad. You can change them without removing the heads. Suggest you get a good set of 'positive' seals, like from felpro (sold at Auto Zone), and install. (The intake guide seals are rubber/plastic, and the exhaust guide seals are a kind of teflon coated plastic, and also use the rubber 0-Ring seal on each valve.) This will probably solve your oil consumption problem unless your valve stem guides are really worn way out of acceptable specs.

TTop Tony

Thanks guys I've never heard of a "leakdown test" before I'll look into it. You know I think I remember the guys on Shadetree Mechanic doing something similar. Boy I wish my memory was better. I know my engine is tired maybe its best to quit band aiding it and just replace it or rebuild it.

79MakoL82

Depends on the gaskets you are using. Valve cover gaskets, you will generally use a little RTV on the cover side to hold it in place, but NONE on the head side. As far as the oil pan, the 3 piece gaskets require sealant, but the Fel-Pro one piece does not. Make sure you torque them properly. They do not require very much torque. Covers are generally 45 lb/inches. The Fel-Pro oil pan gasket 8-16 lb/ft (depending on which bolt). Also, you did not mention you had swapped your manifold. You may want to try re-seating it or re-torqueing it. They generally need to be re-torqued shortly after they are installed. Did the puff start before or after the manifold swap? An improperly sitting manifold can cause both of these problems as well.

The leak down test is a good idea, but I'd fix what you know is broke first.


[Modified by 79MakoL82, 9:24 AM 11/26/2001]

TTop Tony

I'm using cork gaskets. I didn't use any sealant so I'll try adding some. I haven't done anything with the oil pan but I do have a one piece gasket sitting on the shelf somewhere. While I don't remember the puff of smoke before the intake swap it has always been drinking this much oil. And as I say I didn't think much of it because the exhaust is clean otherwise. I'll eliminate the easy stuff like leaky gaskets and work on finding someone to do the leakdown test and work from there.

MELVIN

I WAS GETTING THE SAME THING IN MY BB. ABOUT 1/2 TO ONE QT, GOING 300 MILES, ABOUT 70 MPH

ITS RINGS, NO DOUBT. WHILE THE VALVE SEALS, OR VALVE THEMSELVES ARE GIVING THE BLUE SMOKE ON START UP, THEY WONT EAT OIL THE WAY YOU DESCRIBED. ITS THE RINGS

TTop Tony

Yuck I was afraid of that. Oh well I was planning on a crate motor later on. I guess its going to be sooner rather then later. I knew the engine needed work when I bought it I'm amazed its got me this far. 26 years is a pretty good lifespan for an engine I would think.

79MakoL82

TTOP: The one thing I've learned around here is, there is NOTHING that is "NO DOUBT". Unless an individual is actually working on your car, don't take anything for gospel around here. There's some good advice, but you cannot diagnose anything for certainty without actually seeing the car and working on it. I've had some diagnoses that were right on, and I've had some that were way off. Like I said, fix the things you know are broke (and they are VERY inexpensive), then have a leak down test to check the rings. If at that time you are still eating oil and the leak down test indicates you need new rings and you want to go with a crate engine, do it.

TTop Tony

Oh I agree with you totally MAKO. I will definitly have the engine checked before I proceed. It will be a good learning experience for me. I should have done it when I first got the car I just didn't know any better.
My car needs a paint job so beleive me if I can drive this engine for another year I will. :D

MELVIN

I AGREE, CHECK THE LEAK DOWN. ANOTHER WAY BESIDES A LEAK DOWN IS THE FOLLOWING:

REMOVE ALL SPARK PLUGS, DISABLE IGNITION

PLACE A COMPRESSION TESTOR IN ANY CYLINDER (THE TYPE THAT SCREWS INTO THE SPARKPLUG HOLE, NOT HELD IN PLACE WITH A RUBBER PLUG AND BY HAND) AVAILABLE AT ANY PARTS STORE

TURN THE ENGINE OVER 3-4 TIMES. RECORD READING. RELEASE AIR PRESSURE IN GAUGE. REPEAT IN THE OTHER 7 CYLINDERS. DO NOT CONCERN YOURSELF WITH WHAT THE SPECIFIC READING IN PSI SHOULD BE. WHAT YOU ARE LOOKING FOR IS THAT THERE SHOULD NOT BE GREATER THAN A 10% DIFFERENCE IN READINGS BETWEEN THE LOWEST AND HIGHEST READING YOU GET

WHEN YOU DO FIND CYLINDERS THAT TEND TO READ LOWER THAN 10% FROM THE ABOVE, IS TO DO THE SAME ABOVE WITH THE SUSPECT CYLINDERS. BUT BEFORE YOU TEST, SQUIRT ABOUT A TABLESPOON OF OIL IN THE CYLINDER. CRANK 8-10 TIMES; IF THE PRESSURE BUILDS VERY QUICK, THEN RAPIDLY DROPS, YOU HAVE FOUND A CYLINDER WITH WORN RINGS

TTop Tony

Thanks MELVIN. I'll invite some of my more knowledgable buddies over one day and see what happens. I'll keep you guys posted.

WATTAC

I noticed you'd mentioned you'd replaced your intake manifold. I'd guess you didn't use any sealer around your manifold to head gaskets and you're sucking oil out of the engine valley, into the intakes and burning it. Does this sound like a possibility? Did the oil consumption increase after the intake replacement?

Just some thoughts before you go to the trouble of valve seals and piston rings.

Andy

TTop Tony

While I can't vouch for my accuracy I did use sealer on the gaskets. But thats a thought. I don't think its gotten worse since I did the intake but since my odometer doesn't work I can't tell. I did start driving the car more since then.

79MakoL82

TTop: Try what I mentioned above, and re-torque the manifold in the correct order to the correct specs before you tear off the manifold. Once the manifold is installed and on for a little while, the gaskets and sealers will compress and settle, and you need to re-torque the bolts to the correct specs. Try that before you rip into it again. If that doesn't work, you might consider re-seating the manifold.

TTop Tony

I haven't retorqued it after the install. Sounds like my weekends going to be pretty busy. :D