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Smokey exhaust

my 1989 Acura Legend sedan has (blue-grey) exhaust smoke…not a lot, and not always…but it didn’t pass Virginia emissions testing. I’m not interested in major engine work. Is there a product I can use to swell valve seals? Is there a “smoke-free” motor oil? (ie, to pass emissions so I can get 2 more years from my car)

You can try one of the "high mileage’ motor oils on the market, but don’t expect miracles. There are no pour-in cures for an engine that burns oil.

Dittp to what McP said.
Besides, swelling the valve seals won;t help if the oil is passing by the oil rings. And it sounds like your is.

You could also try a heavier base weight oil. But, again, don’t expect miracles.

Thanks…I’m too old to believe in miracles. I just like this old car a lot, and don’t see the need to get a new one…but $3,500 for a rebuilt engine just isn’t worth it…eswp since it runs just fine. The emissions tester suggested I get swome “smoke free oil,” but I can’t seem to find that such a product actually exists.

I’ve got some straight 50 weight…we’ll see if it helps. For other reasons not stated I actually think it’s the valves. If so, is there a particular time when to take it back in (I get one free re-inspection)…ie, when it’s recently started up…or after prolonged running?

Synthetic oil smokes very little.

How many miles on the engine? How much oil does it use? What are the numbers from the failed emissions test?

When does the smoke appear? If this is just replacing valve stem seals . . . I’d spend the money. Is your '89 Acura similar to my '89 Accord? If it’s the same engine block, it’s an easy job for a mechanic. The valve stem seals get brittle with age and leak oil down into the combustion chanber after you shut the car off (maybe even during operation). The result is a bit of oil being burned upon start-up, a blue cloud of smoke (some big, some small) which goes away after the engine is running. This will eventually affect the emissions system (seems like it has already). Check with a local trusted Honda mechanic to see if this is the case and ask for a ball-park estimate. Rocketman

You don’t want to use a straight 50 weight oil in this engine. This oil is too thick to provide lubriction to the engine at start-up. If you think you’re burning oil now, use that oil and you’ll end up with a real oil burning engine.

Try changing the oil to Valvoline MaxLife of the proper weight.


Leaking valve guide seals will allow the engine to smoke a bit when it’s first started. If the engine smokes all the time it’s more likely the rings. If it’s just valve guide seals I’d spend the money to have them replaced.

Fully warmed up is the best time to test it.

I would NOT put 50 wt oil in the engine, or 40, either… It won’t move fast enough on cold start, and may do more harm than good.

I’d try synthetic oil. It may not smoke as much as regular oil. Use the viscosity specified in the owner’s manual.

miles= 184,000

About 1 qt/1,000 miles

no numbers…he took one look at the visible smoking, and failed it

If your car is actually burning only one qt. per 1,000 miles at the point where it has racked up 184k on the odometer, the rate of oil burning is actually quite good. There are a lot of owners of late-model Audis who would envy you, since many of them add a qt. every 400-500 miles–and Audi claims that this rate of consumption is within normal limits! In fact, if your car was brand new and you complained about burning a qt. of oil every 1,000 miles, your complaint would essentially be ignored by every new car dealership with which I am familiar.

That being said, I would look elsewhere for the cause of the smoke since this is not a high rate of oil consumption.

1 quart per 1000 miles isn’t bad at all, especially at 184K.

It sounds, from your description, like your oil consumption is entirely from the valve seals. If you’d really like to keep the car another 2 years, get them replaced. Valve seals isn’t major engine work.

A fresh set of spark plugs and a clean air filter can help lessen the smoke, and help pass the test.
Before the test, don’t shut off the engine while you wait in line. You want the engine nice and warm for the test.

Research your States regulations on vehicles that “smoke” is it within the “Officals” duties to automatically refuse to test a "smoking"car?

Does your State have a program giving exemptions to “smoking” vehicles?

If your car is visibly smoking after the drive to the test facility,it is not a simple stem seal fix

For use in this suburban area, it must pass emissions. Visible exhaust smoke fails testing…and there is no waiver for this in Virginia. It doesn’t smoke immediately on start up…but soon thereafter. I was quoted $1200-1500 for a valve job…doesn’t make sense for an $800 car! But I’m fond of it…best car I’ve ever owned.

Thanks…good advice.

Why go to straight 50 when the straight 30 is more than enough to stop most smoking. I had a smoke screen Comet that just plain stopped doing it. Straight 30 is also a cheaper oil to buy usually.

Here’s the follow-up. I put in 2 quarts of straight 50 weight oil, plus 2 bottles of an additive made by Barr (something like “Stop Smoke”), and the smoking seemed to decrease. I went back to the inspection station on a cold day, kept the engine running…the inspector attached flexible hoses to the exhaust pipes, then (presumably because of the cold) closed the garage doors, and ran his test. Now, I’m not saying that the closed doors obscured his vision of the residual smoking…but THE CAR PASSED!!! I’ll get (hopefully) 2 more years of use from it, and minimize my carbon footprint in the process. Thanks to all of you for your caring advice.


It’s the same thing when Mom says No! ask Dad.You got lucky,the advice about not using 50W was sound,and this is not proof about “stop smoke”.But this is how myths get mileage.