Help - White Smoke

[bltoe]

Hey all,

Looking for some advice from the gurus please.

I purchased a M50B25TU swapped '88 325 (motor supposedly has ~130k) a few months ago and recently noticed a ton of white-ish smoke coming from the exhaust.

I had made a left-hand, quick turn, into a CVS entrance the other day and noticed lots of smoke in my rear-view mirror. I had been driving for approximately 20 minutes at that time and have never noticed any smoke since purchasing the car. The smoking continued for the next 15 minutes until I arrived to work but seemed to be decreasing in amount. I did not notice any more smoke from the exhaust for the rest of that day (lunch drive nor on way home) and for the next few days.

Tonight I again noticed whitish smoke coming from the exhaust as I parked after driving ~6 miles to the gym. It had a slightly sweet smell though was hard to ID however I am leaning towards coolant based on the color and amount. That first time it was like I had sea-foamed the motor.

The car seems to be running perfectly and is not hard to start nor seems to be missing or low on power. I have not noticed any milkiness to the dipstick. It revs fine all the way to the limiter and the coolant temp needle doesn't seem to be abnormally high (if anything, a bit lower than usual).

Should I perform a compression test this weekend? Sound like a headgasket issue?

The only other issue I can think of is potentially the vanos making a slight-rattling noise. Could a vanos problem lead to smoke from the exhaust? The car is my daily-driver and I need to make it to work the rest of the week

Thanks in advance for any help and I hope I've made some sense...

Dustin

[e46s54dr]

Are you loosing a significant amount of coolant? If its white smoke and sweet (maple syrup smell) then its definitely coolant burning. It might be a sign of a failing head gasket. You should try doing a compression test while the engine is cold, and again when the engine is hot if you have the tools.

Another pretty accurate alternative would be to perform a block test. They sell the kit at most auto parts store about 25.00 or so. It looks like a big ear dropper that comes with a solution bottle. It extracts vapors from the radiator filler neck and if the blue solution turns yellow, it indicates that exhaust gas is entering your cooling system which means either;

Blown Head Gasket (BHG)
Cracked Head or Block
Pulled Bolts or Studs
Warped Sealing Surfaces

Best of luck to you...

[e46s54dr]

Also, Did this happen when your fuel level was low? Theres a possibility that there is water collected in your fuel tank and is getting burnt when your fuel is low. You can buy a bottle of HEET or similar products that are alcohol based to dispersed the water into your fuel to get burnt.

[bltoe]

Thanks so much for the help/advice s54dr. The fuel level was low when it initially happened but over 1/2 tank last night when smaller amounts of white smoke appeared. I am about to leave for work and am going to again check the filler cap/dipstick/coolant level.

I will do a compression test this weekend and go from there. I assume it's a failing HG and I HOPE I can make it a little while longer until I am able to do the job the following weekend at the earliest.

Thanks much,
Dustin

[bltoe]

Well lunchtime update:

No milkiness at all on the filler cap or dipstick. Coolant level appears to be at most slightly below max.

And here's the kicker...it seems to only produce smoke after a hard-ish left turn. Took a sharp left turn on the way to work and instantly smoke out the back. Every time there has been smoke it's directly after a left turn at speed. Any ideas?!

Dustin

[e46s54dr]

Here's what I'm thinking.

Water is heavier then fuel so it'll stay to the bottom of your tank. Liquid droplets like to clump together to form a bigger pool. Your fuel pump and pickup is in the rear right side. So when you make a strong left turn, the centrifugal force will cause the heavier mass of the water to shift to the right side. Therefor causing it to be sucked in and burnt.

Sounds unliikely but it may be worth using some additives to clense your tank from possible water. Espcially if you're seeing all this white smoke without a significant loss of coolant.

[bltoe]

Thanks once again. I'll be sure to keep an eye on the coolant level and will look into some type of fuel additive. I will plan on doing a compression test at minimum this weekend as well.

Dustin

[e30rapidic]

could drain out a little fuel...or water if its really in there since it will be at the bottom anyway. There is a drain plug on the passenger side, believe its a 5mm allen key. You will need to let it soak in penetrating fluid for a while, just to be safe. Jack the car up on the drivers side so whatever it is will flow over there.

If that plug doesn't want to come out, disconnect a fuel hose and jumper the fuel pump.

Or you could possibly remove the smallest heat shield right by the diff and remove the cross tank line to drain some fuel.

Good luck....

[TimKninja]

Is your car running rich?

[bltoe]

E30rapid: I may just try that this weekend. Thank you for your advice.

Tim: it may be running slightly rich. It has a stock 413 ECU. The motor has a cone style intake and eBay long tube headers connected to 3 inch stainless exiting through a magnaflow muffler.
I do not believe the smoke to be oil related but again I am not 100% sure yet. Coolant level hasn't changed though I have been turning left very slowly lol.


Any chance my open-draining CCV could be related?

Thanks all,
Dustin

[bltoe]

Just had another idea though not sure if it makes sense...

Could a leaky master cylinder be responsible?

I've been having to top off brake fluid lately and have yet to find the source of the brake fluid leak. The pedal will all of a sudden go to the floor and be ineffective but after topping off with fluid in the reservoir brake performance comes back...with no air in the system.

During a left turn could fluid be inducted?

[e46s54dr]

Quickest way to tell is to pull the vacuum line that connects the brake booster to the intake manifold. Look into the hose to see if there is any excessive brake fluid/oil residue.

[bltoe]

Excellent, thanks once again! I am going to have quite a busy weekend lol.

[bltoe]

Just wanted to post an update...it was the master cylinder! The MC was leaking heavily past the seal and into the brake booster. The booster was half-full of brake fluid when pulled.

On left turns the fluid in the booster would slosh around to the upper right and into the vacuum line...into the intake manifold.

Thanks again for the help/suggestions.

Dustin

[DREWHALL]

Wow. Not something common but that makes sense. May want to consider replacing the booster if you didn't. The diaphragm inside doesn't like brake fluid.