Hi all,

I just got back inside after working on the mystery smoke issue with my 1985 740 turbo. I have no idea why, but there was too much oil in the engine. The old girl leaks like a cheese grater, so the other day when it was cold I pulled the dipstick, barely any oil on it. I just added a quart and away I went. This morning I check the oil and it's half again up the dip stick over full (if the little flat "X" stamped section is an inch, my oil level was half an inch above it. What the hell?!?!?!

Drained the engine, put in only 4 quarts, and started it up. No smoke. Mind you the engine is cold, and no high revving. I let it get to operating temp and took it up to 4,000 RPM (parked, just revving)and I did get a lot of white vapor - I don't now if that is due to the weather (it is cold rainy and crappy out) or perhaps a slight anti-freeze mix getting into the engine. I saw no vapor upon initial start up, but after it warmed up my tail pipe was dripping water (not anti freeze) so I don't know if that's just condensation in the exhaust system or what.

After it warmed up I did the jiggle test. FAILED. It was hoping around the place like a piece of popcorn.

I am off to remove, clean and replace the PCV crap. So if I clean the PCV stuff, and I still fail the jiggle test, what next? Check all the vacuum line I suppose.

Thanks for any guidance.

JCM
--
'Great spirits have always encountered violent opposition from mediocre minds.' ~ Albert Einstein

The jiggle test only works with metal oil caps. I do not know which one your model has.
--
90 744ti, Airbox, K/N, Cold air, G-Valve, Dual boost control, VDO, Modified exhaust. 88 745 gle.

Sorry to update and run, but I got a wee one to look after.

Long story short it was the little black box. I pulled it and all the hoses. I cleaned all items best I could, but the decided to replace the black box. upon start up with the new black box all was fine, best of all I got an "A" on the jiggle test (yes I do have the old metal car!)

Thanks to all you guys, These turbos are touchy ain't they?

--
'Great spirits have always encountered violent opposition from mediocre minds.' ~ Albert Einstein

Wait untill you start raising the boost that's when the real fun begins.
--
90 744ti, Airbox, K/N, Cold air, G-Valve, Dual boost control, VDO, Modified exhaust. 88 745 gle.

If head gasket leakage is sufficient to cause visible steam in the exhaust, It will usualy pressurise the cooling system immediately on startup.
Start the engine with your hand held over the filler cap hole to find out.

A bad FPR with a fully ruptured diphram can blow white smoke and raw gas out the tailpipe, but should be accompanied by a hefty missfire.

One source of extra "oil" is an engine that's running excessivly rich. The extra gas washes down the cylinder walls -- particularly in the winter when the walls are cold, the fuel condenses, and the FI system compensates by enriching the mixture, which pumps in MORE gas.

The extra gas collects in the oil, dilutes it, and raises the apparent level in the crankcase.

All that gas washing the lubricating oil off the walls does no good, and diluted oil in the bearings is worse.


--
Don Foster (near Cape Cod, MA)

Make absoloutly sure that you are on a leval surface when checking the oil . I've seen one where the folks thought the engine was shot and all it was was they were checking the oil with the car parked on the street on a slight angle and overfilling by aboiut 2 qts and the thing smoked like crazythe combination of that and a cracked hose going to the flame trap made it look hopeless., it wasn't.
--
-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel, '82 Mercedes 300SD

is sort of like a high altitute contrail one sees behind a jet plane.

Exhaust from the cold engine contains a good bit of water vapour (see OPINIONS re: spelling).

That warm vapour-laden gas hits the cold surrounding air and immediately cools, causing the vapour to condense into droplets. Like fog.

So when the engine reaches operating temperature the water vapour is little or none, and the exhaust is (or should be) clear.

White smoke after engine is at operating temp still means water vapour, and that's a signal for a problem like a bad head gasket.

Good Luck,

Bob

:>)
--
240s: 1986 244GL, 1988 244GL, and 5 others.

BC,

If it is the head gasket would it not result in oil in the rad? Head gaskt wouldn't be too bad given the proximity of the weekend, but it is a lot of work. Thanks for the info. I am in the process of cleaning the pcv system, the black plstic box that seperates the oil form the vapors is quite dirty, I am debating if I should clean or buy new.

JCM
--
'Great spirits have always encountered violent opposition from mediocre minds.' ~ Albert Einstein

you could still have a blowen head gas and only burn water, iv seen 2 volvo's so far one with a blowen gasket and only burning water and the other with a blowen gasket and not burning either one, just all depends on where it blows out. Also keep in mind you still have oil in wherever it leaked out take it out on the freeway so you can reach absolute max temp to burn the remainder out.

If you are concerned about water being burnt in the engine, you'd see a noticeable loss in the exp tank.

As for oil trap, remove end of PCV hose from turbo and blow through (clean first!) with oil filler cap off. There should be little resistance.

--
Norm Cook Vancouver BC; 1989 745T 202,000KM