5.7 using oil, no smoke

[Wozny]

May be worth replacing some gaskets while you're at it. If it was leaking from several places like you say, sounds like it may be the oil pan gasket may have been a bit dry from a while of sitting around (presumably with no oil) and then swelled up a bit with fresh oil and use. Not an unheard of phenomenon with cork gaskets, but they tend to fail pretty spectacularly shortly after.

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I wouldn’t doubt that’s what happened, it could have sat for a long time. But it’s still using a quart every 60 miles and no leaks I can see. All I can figure, since it doesn’t smoke, is it’s got to be leaking while I’m going down the highway. I’ve checked it dozens of times and no drips now. It’s really starts up and runs good too

 

[Schurkey]

So if I pour oil onto the valves I’ll be able to tell if it’s going past the seals by listening?

No.

 

[thinger2]

Thanks, I’ll take the covers off, it’ll be interesting to see how much sludge is there anyway. So if I pour oil onto the valves I’ll be able to tell if it’s going past the seals by listening?

Nope. Dig in deep on how to do a leakdown test.
A compression test and a leakdown test are skills you should master if you are going to understand how engines work.
I can already guess that the engine is a crudded up sludge beast.
There are all kinds of old school tricks you can try to slap a little more life into that thing.
Dont sweat about the oil pressure to much at this point.
It is what it is.
A 350 will run on ridicously low oil pressure.
As long as it has enough to trigger the oil pressure sensor so the fuel pump runs.
Think of it as a learning opportunity.
Almost every old mechanic in this country started on a small block chevy.
Keep posting questions anytime and there is no dumb question
ask away bud

 

[Pinger]

Forgot to say, it’s got 140,000 on it, I just got it and don’t know how well it was maintained but the oil was black as coal when I changed it

When you did that - how much oil did you put in?

 

[RawbDidIt]

I wouldn’t doubt that’s what happened, it could have sat for a long time. But it’s still using a quart every 60 miles and no leaks I can see. All I can figure, since it doesn’t smoke, is it’s got to be leaking while I’m going down the highway. I’ve checked it dozens of times and no drips now. It’s really starts up and runs good too

I understand it isn't leaking now, I'm saying if any gasket was leaking and now isn't as you described, it's likely to fail completely soon, and were it me, I'd prefer to change it now before it fails going down the road.

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[Ron88]

What weight oil is in the engine?

 

[jaywestfall]

My 1992 5.7L uses a quart every 60 miles and doesn’t leak or smoke. I do see a little smoke when I take the oil filler cap off but it’s not much, and there’s no smoke out the tailpipe. I don’t think it’s leaking only on the road, because I’ve tried stopping along the road and checking for drops, but there’s none. The compression is around 120-125, pretty low, but if it was burning a quart every sixty miles by the rings or valve guides, wouldn’t it be smoking like a chimney? Well thanks, any and all suggestions would be greatly appreciated because I’m at my wits end

I have a similar problem. Shop says I have a small leak in the block using the dye test. Mines the 5.7 Vortec II in a 98 ext cab.

 

[Wozny]

Right

I understand it isn't leaking now, I'm saying if any gasket was leaking and now isn't as you described, it's likely to fail completely soon, and were it me, I'd prefer to change it now before it fails going down the road.

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Right, thanks. I’ll probably just take it out when I get the time and get it rebuilt. wherever that oil is going now without leaking, can’t be good. It’s had a hard 140,000 on it, the motors is coated in a lot of hard black caked on oil and the inside must look about as bad

 

[mykytiuk]

The direct answer to your question is...no! It is all being burned up by the catalytic converter. This is what they do! If you want to see the smoking chimney effect just remove the cat.

 

[Wozny]

When you did that - how much oil did you put in?

I never have over filled it, but that’s a real good point, I did think about that. Thanks