More problems with my son's car,. 

He reports bad smoke from exhaust when going up hill (black and white) but no great power loss.

The engine has a longstanding oil leak from LH rear side of engine, assumed to be some sort of pipe split, this may or may not be related.

He has also reported that oil level is 1cm above too mark on dip stick. This is rather strange because I recently did an oil change and feel pretty sure it was not over filled, but I could have made an error.

engine is 1.8 diesel 150 k miles EGR blanked.

Any sign of a creamy sludge on the oil filler cap? If there is then I'm afraid to say that it is likely he has a head gasket issue. If not, then an oil cooler somewhere could be letting water into the oil system. That might explain the higher oil level. 

Black smoke says his engine is running rich. Has he had it remapped at all? If so then less of a worry as more soot is normal on a remapped diesel. Second, have you checked his air filter for condition, or intake system for leaks etc? If both are fine, his turbo could be on the way out, meaning its not blowing /compressing as well as it used too. Less air to fuel ratio = rich mixture = black smoke.

His oil leak (if related) needs fixing asap because when a turbo goes, it ain't cheap to fix. Not fixing an oil leak when it is noticed is the same as kicking the can/problem down the road, it only ever gets bigger the longer it is left unfixed. It could be a £3 O-ring with £20 labour to replace, which if not fixed could mean a big end bearing goes costing £XXX+ to fix....or it writes the engine off!! Do not procrastinate on it!

White smoke is often related to coolant being burnt, I refer you back to the potential head gasket issue. They could be related. Get him to have the engine compression tested, that will shead some data on the situation. If it is head gasket, he should stop driving the car immediately and get it fixed. Again he risks completely writing his engine off! That's a good £2500 for a reconditioned engine it £5k+ for a new one.

None of these signs are good, the white smoke would be my first concern.

 

Edited October 28, 20187 yr by blahde2
Typos by autocorrect!!!!