On the way home today, my truck started smoking -- a little a first and then great gouts of white smoke. Well, I thought I must've blown the head gasket or lifted a head, or something... Here's the weird part: No water in the oil, no oil in the water, no decrease in oil or water level... I started it back up and ran it a little and the temp stayed dead on 178* (normal op temp for me). So I drove it a little...

Still no mixed fluids, no decrease in levels, no extra noises, no increase in any temps (hell even the iats stayed 10 over ambient!), but as it drove, the engine roughened up like it was developing a miss, and eventually got really rough.

The white smoke would stop and be replaced by a little blue smoke, then more white, then a little blue, etc. Finally it stopped altogether (although was still running rough), until I was about 2 blocks from home, and voila, more white smoke, followed by blue, then nothing again.

At home I checked the oil and water again: nothing. Checked the tranny fluid: nothing. I looked all around the heads, no signs of leaking oil or water, no outward sign of a lifted head, nothing. Engine compartment is totally dry as is the air intake tube up by the TB. The fluids don't even smell funny...

I haven't pulled the plugs yet, but I'm already stumped anyway...

Any idea what the hell could be going on now?

Oh -- oil pressure ranged from 40 to the big has mark below 40 on the stock gauge. I had the wrong logging profile on the laptop and didn't think to change it to see the actual oil pressure.

Also -- no codes, nothing amiss in either scanner (HPT and megasquirt). Nada...

 

condensation?

 

It was blow head gasket sized clouds -- plus I'd driven it a few hours before. Gotta pull some plugs tonight I guess.

 

sounds like a head gasket to me.

 

Yup .. head gaskets.

Got true duals, then you could see which side it was coming from.

I'm in almost the same boat as you, but mine's only on cold start, little white smoke and rough as hell running, then clears up once the temp reaches ~140*.

 

Ok, everyone sigh in relief on three

I think I found the problem, and it appears to be minor. I found some tranny fluid on and around the vacuum check valve -- looks like I was sucking some tranny fluid through the intake. Probably nerfed the vacuum pump in the tranny, but probably didn't hurt anything in the engine. (course I saw this after removing 5 plugs lol)

I spoke with Chuck Johnson at Finish Line Transmissions (my tranny builder) and he said tranny fluid smokes white like coolant / water and the white smoke / blue smoke thing is exactly what he'd expect for burning trans fluid.

 

Had the same thing happen to me on a turbo 400 when vacuum modulator went out.Glad that's all it was.

 

Hope that is what it is man.
One other item, if the STS oil scavenge pump fails or gets intermittent it will do exactly what you described. The oil will build up and get sucked into the exhaust stream. It does not get really blue ( like a typical oil burn ) because it is not in the combustion chamber.

 

Yep, a few my ol th350's did the same thing...smoked like a mudderfarker.