Intermittent smoke

I have a 1984 Camry with 340,000 miles. Three times in the last six months, it has given off major clouds of blue smoke for 15 to 20 minutes, then gone back to normal. There is no noticeable change in performance when this happens. It hasn’t lasted long enough for me to bring it to a mechanic.

Is there some explanation that won’t require a new engine?


John, that’s a remarkable number of miles without major problems! With that many miles on the engine, the valve guides are one of the first things to start wearing out. When that happens, some oil leaks into the cylinders with the engine shut off. When you start up, that oil burns off and gives a small to medium cloud of blue smoke. Once you are underway at road speed, with the engine warm, and you lift your foot off the gas, the engine vacuum will suck oil past the valve guides and produce more blue smoke.

If your rings were bad, the blue smoke would be more or less continuous. I’m sure you have driven behind one of these oil burners.

If you try this test and you see blue smoke on startup (after car has sat for several hours) and when lifting your foot off the throttle while underway at road speed, it is valve guides. At this mileage you should get an engine evaluation from a competent shop, not necessarily the dealer, and find what other work the engine might need.

Your engine should also be on its 6th or 7th timing belt by now.

Please post us with your findings.

If this vehicle has an automatic transmission, you may want to check the transmission fluid level.

What you might see burning is transmission fluid. The transmission has a vacuum modulator that is controlled with engine vacuum. If the diaphram in the modulator has developed a leak, transmission fluid can be drawn into the engine via the vacuum hose and burned. And this will cause one hell of a cloud of smoke out the tailpipe.


Good reminder Tester. I have not had one of those leaks in years ( a Pontiac Bonneville)and, yes Tranni fluid certainly leaves lots of white smoke.

Here’s a wild guess. The EGR valve might close up for a few seconds and raise the manifold vacuum. PCV hose might collapse temporarily, raising the manifold vacuum. The engine might be pulling the oil through the valve guides at that time. I made these answers up but even I don’t believe them.

The transmission fluid is down near ADD, but that is not unusual. I have had chronic problems with transmission fluid leaks for decades with this car. I always keep a quart in the trunk.

Do all automatic transmissions have a vacuum modulator? I didn’t spot one flipping through the manual (although I could have missed it – the transmission section is 164 pages long).


It’s the 6th timing belt (the original, plus 5 replacements). Fortunately the 84 Camry has a non-interference engine, because twice I was brought it by tow truck for the replacement – once when the water pump failed (I was scheduled to have it replaced on a Friday, but it gave out two days earlier on a Wednesday), and once when the tensioner pulley failed with just 49,000 miles on the belt (you could smell the burning rubber).

It may be a couple of weeks before I get the smoking problem looked at (it’s behaving itself this week). I’ll let people know.