Blue smoke

Hi All,

My car produces blue smoke, usually on gear change but the garage saw it when I was driving up also.

So far they have:

- Checked turbo - no oil and seems ok
- Checked intercooler - no oil
- Done a compression test apparently ok


Originally when I took the car out of the garage it was smoking the same way, but with some engine flush and additives it seemed to go away.

I'm properly stumped now, thought it would be oil seals or turbo.

Does anyone have anything else I should ask to be checked while its still with the garage?
Cheers

Paz

Could be valve seals then (getting common at this age 20+years)
If happening at cold startup too would point at stem seals too possibly as they seep bit of oil onto piston then burns off when started, could pull plugs & see if see any wet oil spots on top of pistons after a night parked up.
Would double check turbo & inlet for signs of oil & check the breather system too, even oil control ring stuck/broken could cause it.

Thanks for the reply!

How would they check valve seals?

I'll ask them to check the breather system too, any simple tips for me to pass on? I know they're a garage but people don't tend to know our cars that well nowadays.

Cheers

Looking for oil drips on pistons after standing good 12hrs & process of elimination of everything else.  If intake pipe super clean right back to inlet then likely stem seals, they old and many have had them done already or in similar situation as you.
Do double check the turbo & the oil return is not blocked, also if using a GT series garrett ball-bearing turbo check you got a inlet restrictor fitted, Having good look down plug holes & looking at plug deposits should give some ideas hopefully.
Things like oil ring issues or even a crack in head hard diagnose but they more unlikely issues.
If it is valve seals I would only use original Nissan (Not expensive), can be fitted with head left on but bit of faffing about.

might be your oil control rings, compression isnt affected by this

if you decelerate down a hill, then hit the accelerator at the bottom of the hill and it smokes when you have started accelerating its a good indication that its the rings.

this was relevant to my honda i had which had an oil ring issue, no loss of power and compression was good