White Smoke?

[queen]

hmm weird. Does it smell like smokey bacon? Mine used no oil to begin with then level siddenly dropped.

These turbos do have shaft play, not along the axis but side to side, its part of the design. I would consider the wastegate actuator, its possible that its not opening the wastegate and therefore your turbo is always spinning. That has no sensor, so maybe its tricking the n75 valve.

Did you try what I asked you to try?

It smells like decat, like unburned fuel.
Mine has shaft play because we checked it some 1000km before and now it has more.
I have the forge actuator.

Idle the car for 15 min, then floor it in neutral and let go of throttle, you should see whitey blue smoke coming from tail pipe.

I tried it today, no smoke at least not any we could notice.

Also coast down hill in gear and re apply throttle gently and you should get smoke again

This one I did on a previous occasion, no smoke.

So far I've seen it happening on 3 different cases. It blows a puff of white/blueish smoke after sitting at a light, and I start going, if I roll from 20mph or if I downshift to like 4k, except for a little less smoke in the last two cases.

 

[AL90]

Once it's started smoking what happens when you acelerate hard?

 

[queen]

Nothing weird. It pulls hard and there's no smoke.

 

[AL90]

Does that still suggest valve seals?

 

[queen]

I have no idea.
The last few days it hasn't blown any smoke.

 

[AL90]

Very strange. Anyone got any more ideas or thoughts?

 

[lucifer666]

yes, maybe your oil has dropped, lowering crank pressures and reducing pressure through valve stems

 

[lucifer666]

also have you been using injector cleaner or octane booster?

 

[queen]

My oil is full. It drinks about 250ml in 3500km, that is 70ml in 1000km or 621miles. I don't think that's a lot.
No octane booster or injector cleaner, just Shell's 100oct gas.
Are you sure it can't be the turbo?

 

[Biker]

yes, maybe your oil has dropped, lowering crank pressures and reducing pressure through valve stems

When you say crank pressure would that be "crank case pressure"?

 

[queen]

I've got some important updates.
Today we did a compression test and got the following results:
Cylinder 1: 12
Cylinder 2: 12
Cylinder 3: 12.2
Cylinder 4: 12.5
The spark plugs were all good except for cylinder 4, which was pitch black and there was oil pooling in the space between the gasket under the electrode.
Moreover my coolant has formed an oily layer in the tank.
Cylinder 4 compression is possibly elevated due to moisture forming around the cylinder and some probably leaking past it.
So, must be the head gasket, but the tear must be hair thin as I have minimum oil/water loss.

We switched the black spark plug from cylinder 4 to 3 and we'll be monitoring it for about 1000km and then we'll check again its condition to confirm.

Your thoughts?

 

[queen]

Turns out the white smoke was from the turbo. It's all sorted now.
The layer in the tank wasn't oil after all. It was something like foam due to old coolant.
Now the cooling system has been flushed and filled with new G12.
The spark plug turns out it was random as it didn't do it again.

 

[lucifer666]

Keep an eye on cylinder 4. It's usually the one that goes. Expect that plug to be whiter than others. If your piston is starting to go it would allow oil up into combustion chamber. that may explain the higher compression. Just take the plug out every month, very easy job just to make sure.