Massive oil use, looking for suggestions

[zieg85]

I have an excellent running 95 C1500 Silverado with 122K miles on a 5.7L.  When I start it, it smokes a little but no excessive.  It goes away within a minute or two.  It goes through a quart of oil every 400 miles or so maybe more.  It doesn't leak and it isn't in the cooling system.  It passed the emission test recently.  As I said it runs great, gets decent gas mileage 15 or so country driving by a 17 year old.  I haven't changed anything other than the oil and the needed brake repairs and exhaust system since I purchased it.  Any suggestions???

[VileZambonie]

You can try replacing the valve seals and see what happens.

[zieg85]

The valve seals were my first thought, I just can't imagine that the little smoke on startup can be that but it is worth a try.  My sister-in-laws minivan (non-GM) huffed out blue smoke and leaked like a sive went through less oil than I am.  Any other thoughts???

[85MudMonster]

any idea's at all as to where it may be coming from? I had some oil leaking from my drain plug on mine, but it wasn't like a quart a day or nothing...also when you guys say valve gaskets I assume you mean valve cover gaskets right, that would be my first thought, that's where mine leaked from as well....

[zieg85]

I was talking about my sister-in-laws van.  My 95 is bone dry, no leaks... The oil just vanishes.

[77c15]

The oil may appear to be vanishing, but you'd be surprised as to where it actually goes. If it's leaking through the valve seals or the rings, then it's getting blown out the exhaust. If it's coming from the rear seal, or any other major gasket, it could be traveling down the transmission and getting dropped or flung on the road from the driveshaft. My 77 had a rear main leak, and it would never leak a drop sitting still. The second you started driving, oil would spit out and I found some as far back as the rear bumper on a windy day. Your best bet is to leave a piece of cardboard under it overnight and see if you can find any "sitting" leaks, which would tell you to search for a gasket leak. If that doesn't do it, look around the transmission for any oil. I would even goes as far as to reaching my hand around in the transmission tunnel and the back of the engine to make sure it wasn't an intake manifold gasket or that little oil pressure switch leaking. A quart every 400 miles seems pretty extreme, but it depends on where it's going.

[zieg85]

The underneath of the truck is bone dry, no leaks anywhere.  It is parked on a cement driveway, no drips...  I have followed the truck around.  No blue smoke that I can see.  It has a brand new exhaust system with new donut gaskets and exhaust manifold studs.  I was underneath to look at the truck up on the hoist at USA Muffler where they installed it.  No oil in the exhaust pipes and like I said it passed the Indiana emission test which runs it on a treadmill.  The antifreeze is clean and the oil is not milky either at the dipstick or the oil fill cap.  What I can see through the oil filler opening on the valve cover the engine is not all gunked up.

[VileZambonie]

what kind of vehicle are you talking about here?

[85MudMonster]

okay, I see now, that is weird. It's almost got to be burning it off if there is no visible leaking....

[zieg85]

what kind of vehicle are you talking about here?

1995 Chevy C1500 5.7L with 122,000 miles or so

[VileZambonie]

OK very confusing, at 1st I thought you were talking about your truck then a minivan and now your truck again. OK, so your truck has no oil leaks but burns oil. You only see smoke when you first start it. Right?

[zieg85]

OK very confusing, at 1st I thought you were talking about your truck then a minivan and now your truck again. OK, so your truck has no oil leaks but burns oil. You only see smoke when you first start it. Right?

Yes you are correct.  Sorry for confusion.  I was just thinking of past vehicles that burned/leaked oil that I knew of but not as much as what I am going through. 

[VileZambonie]

Then I would just replace the valve seals and see what happens.

[1976Scottsdale]

They sell a cheap adapter for the spark plug holes for that don't they?  That way a person can put on the seals without pulling the heads?

[Redneckchevy]

Im pretty sure ur thinking about them things that makes it burn hotter?