huey_33

Ok, as some of you may know, I have a major oil burning problem. And I know for sure that it is burning oil because there are no leaks, puddles or anything in my engine bay or on the ground. And the big puffs of smoke that blow out of my exhaust isn't a major giveaway either. I only know of a couple possible suspects on why my car is burning oil. Bad rings or bad valve stem seals. Are there any other possible parts that may have gone bad that is causing my car to burn this much oil? Also, what are the tests that I could have done to my car other than a leak down test to see where the oil is coming from? Can i have these test done at any shop or does it have to be done at a performance shop? Sorry for all the questions but I need to get this thing fixed before my drive from NC to TN in april. Don't feel like having my car failing on me while im on the highway. Thanks.

cliffyk

Does it always smoke when you accelerate--or smoke when you are decelerating, or only when accelerating after an extend period of idling?

If the former then it is likely rings (and/or of course piston/cylinder wear). The rich mix when accelerating washes excess oil, left behind by the bad ring fitment, off the cylinder walls and it gets burned up. When you back off at cruising and the mix leans out not as much gets washed off and burned.

If it smokes during deceleration, or only when coming off a long traffic light/etc., then it is likely valve seals/guides. The high manifold vacuum when decelerating sucks oil past the guides into the combustion chamber, which gets then burned up.

Also characteristic of leaking seals/guides is that sometimes during an extended period of idling the oil gets sucked past the guides, but not burned up at idle speed, it just collects in the combustion chamber.

When you next accelerate it does burn, but then after things get sort of back to normal 'til the next decel/long idle. If bad enough the oil will build up to where the idle starts to stumble, or even stall...

98redstang

+1 this was my problem and why i got my motor built. At first we thought it was the vavle seals so we changed all of them in hope that that was it. But in the end it was the rings. But i got a nice motor out of it haha

huey_33

Doesn't smoke during decelleration at all. Just smokes when I take off after a stop light or stop sign, smokes if I press the gas pedal when car is in park and yesterday I noticed a big puff of smoke after I went WOT to pass a bunch of slow a$$ cars on the interstate. Thats the first time it has done it on the highway. And after I turn the car off, smoke will continue to come out of the left tail pipe for almost a minute or two. Car idles fine and doesn't seem like it wants to stall at all. I had a pretty good feeling that it was bad rings. Don't have the money to get engine rebuilt or to get any major work done so for now Im just going to have to buy new pistons and rings and hope that nobody tries to rape me for labor costs.

cliffyk

I agree, it sounds like rings, a dry then wet compression test will verify this. One other question, how much oil does it consume? Ford says 0.75 to 1.0 quart per 1000 miles is normal. This is when running the 5W-20 donkey ****.

Have you tried running 10W-40 oil? I run that year round here in Florida in all our vehicles and we routinely run them up to 200k+ miles (when I switch 'em over to 20W-50). Now that the weather is warming up where you are 10W-40 would be fine (actually the low temp end for 10W startup is -5°F) and would likely reduce the "puffin' o' the smoke".

Replacing pistons and rings is 90% of a complete tear-down (pretty much right down to a bare block with just the crank remaining), and 15% to 20% of a rebuild--if money is an object how 'bout looking for a used engine?

huey_33

I have tried for weeks now to look for a new engine. But I just can't seem to find one worth spending that kind of money on. All the ones I have found around here have over 100,000 miles on them which will just lead to the problem I am having now. Put it this way, I changed my oil almost two months ago now and 2 weeks ago my car died because there was hardly any oil left in it. And I don't have a leak. So something fishy is going on with my car. I just might have to bite the bullet and spend a little bit more than I want to. If all else fails, I just might have to get a new mustang. But dread the car payments.

cliffyk

My mother had a '74 Chevy Vega years ago that burned 1 quart in 35 miles. She carried a case of oil with her and added a quart before driving to work, and before driving home.

How many miles on your car? I have almost 100k on my '03, my brother has over 145k on his '99, neither burn a drop...

Have you checked/replaced the PCV valve? A PCV valve that is stuck open will cause the engine to gobble up a bunch of oil.

Another possiblity would be a blown head gasket--get/do a compression check before you tear down the engine.

huey_33

it has 155,000 miles on her now. Havent checked the pcv valve or anything. So I guess thats what I will be doing whenever I get another day off. Will it burn the oil though if the valve is stuck open? Also, can any shop do a compression test or leak down test or do I have to take it to a performance shop? But wouldn't the coolant and oil be mixed together if I have a blown head gasket? Because nothing is mixed together, i checked that the other day.

cliffyk

The PCV valve will swill down oil like a painter sucks down beer if stuck open.

Any reasonably competent repair shop should be able to do a dry and wet compression test--if they can't then they are not "reasonably competent" IMHO.

If a head gasket failed with only a breach between an oil galley passage and the cylinder (which may or may be possible on our cars, I've never looked at the block to head passages that closely) then it could pass oil but not coolant...

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Also I have to be honest, letting it run 'til it stops because there's no oil is not helping things--you need to check that oil more often, especially now that you know it's burning it up. I check my oil 2-3 times a week. It doesn't burn a drop, but if and when it does I want to know right away!

huey_33

thanks cliffy, i appreciate everything you have reponded with. Looks like i have a busy couple days off. Need to get my car ready for the state to state drive next month.