engine and drivetrain Random Intermittent Puffs of White Smoke

[pminasi]

After driving the car hard (70+ on the highway) or uphill on the freeway, I get a small puff of white smoke from the exhaust when I let off of the gas. This doesn't happen all of the time, just sometimes.

I hope I can rule out valve guide seals as the head was recently rebuilt (thanks to a cracked block which will soon become the base of a lamp) with a brand new cylinder head block by a very reputable shop and mechanic (George at H&B in Berkeley).

There is almost zero oil consumption, and pre cylinder head cracking, it did this sometimes too.

The car has a weber carb, with a K&N like air filter. Could it be that the oil from the vent tube that builds up on the Air filter base is being sucked in on deceleration (i would assume there is more blow by during long stretches of high engine speeds and I know that there is a higher vacuum draw when you let off the gas but the car is still moving fast)?

I have read a couple of posts about brake fluid potentially being the cause, but the brake fluid level is constant.

Thanks again for any help!

P

[Hans]

Three possible sources:oil, coolant, brake fluid. First clue is obviousy dissapearing fluid. I belueive coolant is more viisble at idle. Brake fluid can be sucked in under high vacuum - e.g. lifting off. Sounds more like oil and I'd go with rings. If other two fluids are stable, try a compression test.

[Simeon]

Here's a suggestion : how about an oil leak from the exhaust studs on the engine running down and being burnt inside a hot exhaust manifold?

[pminasi]

The shop ran a compression test prior to disassembling the engine for the cylinder head work. The numbers were 150 across all four cylinders. I was told that the rings and cylinders looked fine - which keeps the mystery open!

P

[Hans]

I'd start carefully monitoring fluid consumption. Mark master cyl with tape, note oil and water levels. If oil was getting into ex. manifold, you'd hear the exhaust leak under the hood.

[pminasi]

Thanks. Will do. By tape, you mean on the brake reservoir I assume? Also, where should I look for leaks from the master cylinder?

[nbristow01]

Did you have new brass guides installed? These will wear over time and when you do a long decel and then tap the gas you will get a puff of blue smoke. You may also want to check and make sure the vent on your valve cover is clear and the car is breathing ok. Just like a piston will displace air when it goes up the cylinder it also displaces air when it come back down...This downward travel causes crank case pressure.

I am no pro but my guess, if it is blue smoke, is guides or worn valve stems

[TobyB]

I vote brake fluid's built up in the booster.

But even decent valve stem seals can let a little oil by-

it IS a 50 year- old design, you know. And just a tiny bit of

oil on the exhaust valves makes quite a bit of smoke.

Try a synthetic oil and see if it reduces it.

Or somewhat tired (or gunked- up) oil control rings. You'll

get decent compression readings, but in high- vacuum situations,

just a little oil will get sucked in.

If you're not losing fluids at a noticable rate, I wouldn't worry about it.

In fact, I don't. It's a useful way to piss off tailgaters.

t

[Hans]

If the seal at the back of the master cyl is weak, fluid gets by it into the booster servo unit, and then gets sucked down the hose from booster to intake manifold. Over time, your brake fluid resevoir level will drop. The tape makes it easier to monitor. Your compression test sounds OK assuming nothing has changed.

[c.d.iesel]

for a test route the cam cover breather hose

into a used oil bottle as a catch can - placed down behind

the inner fender- to the rear of the fuse box.

cut holes on top of the bottle to let air out-

the hose nearly touching the bottom inside the bottle

to keep the oil/water sludge in there.

what oil are you using ?____

last time yu changed it ? ______

change it to 15w/50 or 20w/50

prefer MOBIL 1 if you can afford it

now DRIVE and report back in 150 miles

......and ther's nothing ' random ' about a 2002 smoking !

[nbristow01]

If you really want to see some 02's smoke come to the Mid America event at the end of April. There are some long decels and wow talk about some smoking cars!! We should be renamed to Ozone eaters LOL

[eurotrash]

If you really want to see some 02's smoke come to the Mid America event at the end of April. There are some long decels and wow talk about some smoking cars!! We should be renamed to Ozone eaters LOL

Plume PLUME plume.. Thats what I always say.

[pminasi]

Thanks all for the suggestions. The car is off being painted right now, but I will check out all of these suggestions and report back. I think its the brake fluid too, rather I hope it is, seems more manageable to repair if it is. The reason I think this, is that the brake pedal had not felt as tight lately.

[pminasi]

Thanks all for the suggestions. The car is off being painted right now, but I will check out all of these suggestions and report back. I think its the brake fluid too, rather I hope it is, seems more manageable to repair if it is. The reason I think this, is that the brake pedal had not felt as tight lately.

[Hans]

All the more reason to watch the brake fluid level closely.