Guys, I need your help...more oil probs

[stang1986GT]

I've posted before about my '86 5.0. Bone stock, GT, 5 speed, etc. When I got the car, it was using about a quart of oil every 200 miles. Rear main was leaking, and the rear of the intake was leaking severely. So, here's what I've done:

New rear main seal. No longer leaks. New intake and valve cover gaskets...no longer leaks. Oil pan seeps very little. Does not smoke at start up, while driving, etc. (The only exception to this is if you're sitting still and rev the engine real hard (like you're not supposed to do), a very small puff of blue smoke will come out). Tail pipes are not wet with oil and it does not appear to be misting oil out the pipes. Front seal is dry as a bone. Spark plugs were beautiful. Not black/drowned with oil. Nice, grey look like they're supposed to be. I have not done a compression check, but with the plugs dry and the fact the runs like new I wasn't sure I would need one.

My problem: OIL IS STILL GOING DOWN! It's better now...about a quart every 400 miles now from what I can tell. Any ideas what the problem could be? Yea, I know these engines use a little oil...mine has a lot of miles...over 120,000. But it runs so perfect and doesn't smoke? Is it possible that the valve stem seals are leaking and it still not smoke? What about rings? If the rings were leaking, wouldn't it smoke or make the plugs black? I realize the rings are letting a little oil by, or it wouldn't let that little puff of smoke when you rev the engine hard as I described above. But if they were leaking badly, it would smoke while driving. It doesn't even smoke when you pull out hard, up/down hills, etc.

Also, when I took the intake off, there seemed to be a good bit of oil residue (not dripping...just coated) in the upper intake. Maybe I need a catch can? Could that make it use that much oil?

I appreciate your advice here. I'm at my wit's end. I don't mind putting a little oil in once in a while, but this is excessive in my book, especially since it's a daily driver. HELP!!!

 

[rd]

As an old school aircraft mechanic once told me, its cheaper to just put a little more in once in a while than to fix it.

302's sometimes seem to do this. My 87 rebuild used a quart every 800 miles for 95,000 miles. Never fouled plugs, did not leak much, just seemed to use oil. Changed heads once to make sure the valve guides or seals were not the problem. Fresh heads, new guides, new seals, no change.

That engine is still in my hot rod, with a couple hundred passes on it now. In a year, 1000 miles and several dozen passes, I add maybe a quart. Go figure?

I believe when these were new, Ford indicated that a quart in 6-800 miles was acceptable, and they would not fix it under warranty.

You could try replacing the valve stem seals. but otherwise I would not worry much about it.

 

[stang1986GT]

As an old school aircraft mechanic once told me, its cheaper to just put a little more in once in a while than to fix it.

302's sometimes seem to do this. My 87 rebuild used a quart every 800 miles for 95,000 miles. Never fouled plugs, did not leak much, just seemed to use oil. Changed heads once to make sure the valve guides or seals were not the problem. Fresh heads, new guides, new seals, no change.

That engine is still in my hot rod, with a couple hundred passes on it now. In a year, 1000 miles and several dozen passes, I add maybe a quart. Go figure?

I believe when these were new, Ford indicated that a quart in 6-800 miles was acceptable, and they would not fix it under warranty.

You could try replacing the valve stem seals. but otherwise I would not worry much about it.

A quart every 6-800 miles? That's crazy. That's enough to make me to go GM...or at least MOPAR! (kidding). My dad had a 90 GT convertible and it didn't use a drop of oil. I guess some of them did, some of them didn't. I still love the car, though. Just never did like having to add oil to a car all the time. Thanks for your thoughts!

 

[DMAN302]

PCV valve may be an issue..put in a separator and see how much it's collecting. Likely a blowby issue and the idea of cheaper to add then fix is not a really bad idea if she's running well.

 

[stang1986GT]

PCV valve may be an issue..put in a separator and see how much it's collecting. Likely a blowby issue and the idea of cheaper to add then fix is not a really bad idea if she's running well.

I remember reading threads about these, and someone here makes them, don't they? Wonder if it would be hard to make one?

 

[DMAN302]

Any company that sells air compressor parts will have them..even walmart I think. They use them to knock out water from the air lines. I just walked through my shop and found an item I could fab a mount out of, and anchored it on my firewall. I looks cool..get lots of inquiries.

 

[stang1986GT]

Any company that sells air compressor parts will have them..even walmart I think. They use them to knock out water from the air lines. I just walked through my shop and found an item I could fab a mount out of, and anchored it on my firewall. I looks cool..get lots of inquiries.

Yep...been reading other posts on using a seperator. So does that mean that I'm losing that much oil through the PCV (assuming rings and other stuff is good). What I mean is, am I going to have to drain the thing every day with this type of consumption? Also, I read in another post that someone took a pipe fitting, drilled a 1/16 hole in it and put it in the tube that goes from the filler neck to the TB and it greatly reduced oil consumption. Wouldn't this increase the vaccum on the PCV valve side?

 

[DMAN302]

I run a clear fuel filter (or will be,not in yet)from valve cover tb...just a nice bling pc for the enginebay, and again knocks the oil out. The good news is you will be keeping the oil out of the combustion chambers, and nothing but good will come of that.

 

[kj2833]

A quart every 6-800 miles? That's crazy. That's enough to make me to go GM..!

Youve never owned a cadillac huh? Thats one GM product that could be worse than what you are experiencing.

 

[wht93gtEd]

Between oil changes, ie: 3k miles, I usually have to add 1-2 quarts. My car doesn't leak anything...it's bone dry underneath. it doesn't smoke either.

I've had friends and other Mustang people drive behind me to look for smoke but nothing, so I've just accepted the fact that my car uses oil.

 

[mustangman140]

thats funny my car will puff the blue smoke like yours does when you dog it but does not use not a single drop of oil ever. all i do is change it ever 2500 check it when i fill up.

 

[Stang8URMPRT]

You guys might want to check on your oil temperature... If it's too high, you can get oil burn off, inwhich you won't see it come out as smoke, and it's not leaking.

Nick