Burning oil

[alec_b]

Pertaining to the new '01 Impala:

 

3800 SII obviously, just in case.

 

When I got it it was right after my buddy had fixed the OPS, but he'd never gotten around to really cleaning up the mess. I did a thorough degreasing of the underside and paid careful attention to the manifold. Well, it still smelled like oil burning.

 

So I cleaned it up some more, and looked close for any oil leaks that would cause the smell. Used a mirror to look all along the edge of the rear valve cover which surprisingly isn't leaking.

 

After all this I finally figured out that the smell isn't oil burning externally, it's INTERNALLY. I'm smelling the oil burning through the exhaust! Ok now, why is it burning THAT much oil. The exhaust is literally blue, not all the times but if you really wind it out you can see it behind you. I'm keeping my eye on just HOW much it uses, as we've only had it about a week and my sister doesn't put many miles on the car.

 

At this point, I'm thinking a good sea-foam treatment through both a vacuum line and in the crankcase might be a good idea. I don't usually see 3800's burn oil that much, hell mine doesn't even use a quart in 3000 miles and I know it leaks a bit. Anyone have any other ideas?

[RobertISaar]

hmm.... i can't remember which is which, but under high load, i think that's showing bad rings, and if it happened under no load at higher speeds(let off the throttle, downshift at ~60MPH), it would be valve seals, but i may have those mixed up...

[Schurkey]

PCV system operating properly?

 

Clogged PCV can cause external oil leaks, un-baffled or un-restricted PCV can cause the PCV system to vacuum-clean any oil mist right into the intake manifold--high oil consumption results.

 

I'd also be looking at a compression test and a cylinder leakage test as well. And that way you'll know what the plugs look like.

[Galaxie500XL]

X2 on valve seals, or could be worn valve guides. Do the compression check. If compression is good, then you're likely just looking at either replacing valve seals, or having the heads rebuilt.

 

If you're looking on keeping it a long time, don't let them knurl the valve guides, have iron inserts installed. They'll last much longer than simply knurling the guides.

[Schurkey]

don't let them knurl the valve guides, have iron inserts installed. They'll last much longer than simply knurling the guides.

While I agree that knurling is a crappy way to repair valve guides, I'm wondering what's wrong with thinwall bronze inserts (as opposed to "iron inserts".)

[xtremerevolution]

Don't do anything before you get a compression test done. Afterward, change your PCV valve to rule that option out.

 

This could also be the LIM gaskets. IIRC, both coolant AND oil travel through those gaskets. Were those gaskets ever replaced?

[tornado_735]

If there is smoke at start up, I was told that indicated leaky valve guides, because the oil has leaked down onto the valves after sitting.

 

Smoking under acceleration is indicative of bad rings.

 

A Rover guy I know swears by Engine Restore, as long as you flush that engine damn good before you use it.

[xtremerevolution]

If there is smoke at start up, I was told that indicated leaky valve guides, because the oil has leaked down onto the valves after sitting.

 

Smoking under acceleration is indicative of bad rings.

 

A Rover guy I know swears by Engine Restore, as long as you flush that engine damn good before you use it.

 

Don't use bandaids to fix your car. Replace those valve seals. I've done it before with the heads off and it isn't a very big deal. I'm sure you can do it with the heads on the car, removing nothing more than the valve covers. Just make sure you don't drop that valve in there or you'll be pulling the heads for sure. The seals should hold the valve as you're removing the spring. Once the spring is off, you should be able to hold the valve as you pull the seal off, and push the new seal back on.

 

That is of course, if you're certain this is the problem. My L27 had 217k miles on it and the valve seals were in excellent shape.

[AL]

Or I have a pair of L36 heads with 102k miles on them I could possibly sell...

[Galaxie500XL]

There's really nothing wrong with phosphor bronze inserts...I'm old school, been doing this sort of stuff since the early 70's, and forgot all about bronze.

[Galaxie500XL]

Or, get a 1/4 inch nylon rope, about 6-8 feet of it. Feed it into the spark plug hole as far as you can, then slowly turn the engine by hand until it can't move any more. The rope will be compressed by the piston into the combustion chamber, which means it will hold the valves in place while you remove the keepers and springs on that cylinder. Do your thing, then turn the engine back a bit to ease up tension on the rope, and pull it out of the spark plug hole.

 

Also works great for keeping the engine still when working alone, and you need to tighten harmonic balancer bolts..

[AL]

Never heard of that but thats genious!!!!

[alec_b]

Thanks for all the suggestions guys. I'll see what I can do to swap out the PCV valve, I'm not sure when I'll get around to a compression test.

 

The LIM gaskets and UIM are both recently repaired.

 

I know it's burning oil both at idle and under load. I'm still keeping my eye on it.