White smoke on deceleration?

[Slightly Larger Roundies]

I get some white smoke on deceleration when slowing down from 60ish. The car has not been driven for the past 10 years. Just got it running good today. Is it just "blowing out the cob webs" so to speak or is this the symptom of a nother problem?

Thnaks!

[mike472]

Sounds like valve stem seals if it only happens on deceleration. Once you close the throttle at higher speeds you create a high vacuum in the combustion chamber which will draw down oil through worn valve guides and/or valve stem seals. They may have dried out in storage and broke up when you started the engine. Newer seals that BMW now uses require new style guides and do a better job of sealing. You can also get Teflon stem seals that are even better if you want to go the extra mile. These require machining the end of your valve guides to put a groove in to hold the seal on. Head has to come off and if you have to take it apart you may want to think about just having it rebuilt by a competent shop that has the proper tools. Do a compression test before you take anything apart so you know the general condition of the engine. Try an Italian tune up first to free up anything that might be stuck. By the way, did you change the oil?

[Slightly Larger Roundies]

Uh... yes I changed the oil. 10w40. New filter. The car has good power. Compression test next I guess... BTW what is an "Italian" tune up?

[Gordon]

It's no big deal if it only happens on deceleration. Bad valve seals are a common issue on high mileage M10 motors. When it gets real bad, then it's time to do a valve job and the head will have to come off. Just check the oil often. In the mean time, just drive it and enjoy it and hopefully no one turns your car in as a gross polluter.

G-Man

[Simeon]

An italian tune up means: Drive it (at speed limit of course) in a low gear and high revs for a reasonable distance, say 30 minutes. Basically give it some welly! (as they say where I come from). Not entirely sure of the science behind it but it is damn good fun! My car sees a lot of low speed traffic jam driving so I try and compensate with one high speed run a week to shake off some carbon. Diesels definitely perform better and smoke less when you do this. Always used to run my diesel Land Rovers at high revs on the way to the MOT and emissions test in the UK.

Maybe try some of your favourite upper cylinder lubricant in the fuel / oil as required. can't hurt.

[mike472]

Uh... yes I changed the oil. 10w40. New filter. The car has good power. Compression test next I guess... BTW what is an "Italian" tune up?

Basically what Simeon said is an Italian tuneup. A good 1/2 hour highway drive will help in 4th between 3500 and 4000 RPM. It will help keep the carbon off the valves.

You should also be using 20w50 weight in the summer months or warm weather areas. 10w40 is good in cold weather when the temperature really drops. 20w50 is a little thicker in viscosity and less likely to get sucked down the valve guides. You might try a good synthetic oil like Redline or Amsoil to help free things up a little too. It's good you used a little thinner oil for a car that's been sitting awhile. The thinner oil might help dissolve some of the sludge in the engine. Give it a good run then dump it for the thicker oil.

[flyingjolly]

+1 on the 20w50

[02Les]

Wouldn't worry too much about it.

I bought my Touring in '86 with 70k on it and it deposited light blue smoke over the cars behind.

It now has 120k and it has got worse, but, every cloud (no pun) has a silver lining, the drivers behind me keep their distance. No need for a 3rd brake light.