I have a 5-speed Saturn, 1996, that failed inspection in New Jersey due to a visible smoke problem. There is a grayish or white smoke ( I can’t really tell which since the smoke is quite thin) being emitted from the exhaust pipe. The shop wants a ridiculous amount to tear down the engine to find the problem. Anybody know what the problem is likely to be, or have a magic potion I can pour into the gas tank to temporarily stop the smoke? But seriously, I have heard of some type of additive from Pep Boys or the like that suppossedly will get the car past an inspection. Anybody had any luck and have a recommendation?
White smoke out your exhaust usually indicates burning oil. Since oil is distributed throughout your engine on all the pistons, camshaft, etc; burning oil can be an indicator of a serious engine problem that is waiting to happen. That’s why they want to tear your engine apart. Usually a seal or gasket may be leaking oil into the combustion chamber an this creates the white smoke you are seeing.
A real mechanic will be able to tell you what is causing the white smoke, but I’m guessing it will be quite expensive to come to the root of the issue. If your car isn’t worth that kind of money, you may want to look into purchasing something else in the near future.
On a car light smoke typically means a few things.
Excess oil consumption due to worn rings and/or valve guides: this might be diagnosable with a simple compression test, but sometimes not.
Blown or leaking head gasket: This might be diagnosable with a compression test and inspection of the oil and water.
Mixture: On a Saturn of that year, I should hope the computer would have a trouble code about that.
Bad catalyst: An emissions test should tell that.
None of these things should be all that hard to diagnose, but some can be very expensive to fix. Actually, potentially all of them could be hundreds.
You have to know the root cause really to know how to pass inspection. You need to find out of the smoke is really oil, unburned hydrocarbons, water, or a mixture. And if you plan on driving the car for some time, it might be better to find out what’s going on and see if it can be fixed.
…or you can wait a little bit…
25 years old cars don’t require pollution tests.
…sorry… good luck 
I could have sworn that white smoke was usually water vapor from a coolant leak and burning oil made blueish smoke…
Do the basics first.
Change your air filter & your breather filters(s).
Use only regular unleaded in your tank before the tests (additives or high-test can make it worse!).
A basic tune-up can help loads.
White smoke (as in WHITE, like clouds or clean cotton) means water getting into the cylinders, usually from a faulty head gasket. Vehicle will also have coolant loss.
Gray to black smoke means excessive fuel going through the engine. Vehicle will also have very high readings on some exhaust gasses, and fail emission inspection for those.
Blue smoke (very pale blue, often tricky to distinguish from whitish or grayish) means oil being burnt in the cylinders. It’s a pretty good bet this is what you have.
Typical causes of oil smoke are worn valve guides and/or valve seals, faulty PCV system, and faulty piston rings.
Saturns are notorious for oil control rings sticking. The proper fix is ring replacement, which is major (and expensive) engine work. Often the sticking rings can be freed up enough to work reasonably well by soaking them in GM Top Engine Cleaner. Remove the spark plugs, pour some through the plug hole into each cylinder, and let it sit (overnight is suggested). Before replacing the plugs, crank the engine to expel any remaing liquid in the cylinders (makes a mess, but beats bending a rod). Multiple treatments may be required. Doesn’t work in every case, but it’s a lot cheaper and easier than a ring job.
I concur with GaryT. Most likely cause is faulty rings/scored cylinder.
While his solution is sound I have found plain ol wd 40 (from the gallon can not the spray) is eaiser to find and seems to do the trick. Make a note, as gary didnt mention this, your engine will smoke much worse immediately following the treatment.
If the car is not one you really care enough about to repair correctly, there is another course of action. (try the ring soak method first)
There are kits available consisting of pellets made of asphalt and copper you drop into the spark holes that will form a temporary fix. These work by coating the piston/ cylinder with a thick gunk that seals the combustion chamber.
My experience is they last less than a month and require a cylinder hone and re-ringing at the very least Most likely a new set of pistons too) to repair the damage they cause. But then again that’s what you’re looking at now.
Thanks all. We just want the car to last a few more months, and need it to pass inspection. I had the car out today and detected no visible smoke whatsoever, even though I did see some a few days ago. What gives? I was thinking of just taking it back to the inspection center and getting it looked at again. I live in New Jersey, and they require you to tell them what repairs you made, so I might just tell them I had a tune up or something . Does anyone know if they will just do a visual check for smoke from the exhaust?
Not sure I understand – did they do the test, and fail you due to the actual emissions, or just see the exhaust smoke and fail you on that basis? I’m not in Jersey, so I don’t know how they handle things there.
Simple white smoke is just water, as has been said, and a can of Dri-Gas and a spin around the block will cure that. (Actually, three cans of dri-gas and a twenty mile hard drive once got me through emissions with a car that should have been failed on sight.) But, it is a Saturn, so, hey, you’ve got tin foil rings, pistons made out of old DelMonte cans, an engine block that you could almost lift from the car with one hand, and the damned thing has lasted for eight years, which is a miracle right up there with Joe Leiberman being taken seriously. I’d dump in two or three cans of dri-gas on top of about five gallons of mid-grade unleaded, run the sucker hard for about ten miles, and go back for a re-test and see what happens.
Gairloch.