bud22405

Spent $3400 2 weeks ago on 106K 996 to fix driver side oil leak from cam covers, driver side axle seal, and AOS tube. Replaced AOS and did new plugs and coils. Mechanic said substantial oil was in spark plug tubes but plugs looked good. After coming home, had 5-10 secs of substantial light blue smoke on startup after car sat overnight after a hard run. No CELS or other noticeable problems other than blue smoke on startup that tappers off after 6-10 seconds. Car reaches redline with no loss of power when run with no sign of smoke between automatic shifts. Every morning since I've had the blue smoke on startup but after sitting more than 6-7 hours. Oil fill tube has slight vacuum with small amount of scum but I can remove cap and engine only falters slightly when cap is off. Mechanic now waiting for special manometer tool to test for defective AOS. Says may also be leftover oil residue or even bad valve seal. Intake is dry and oil level normal. I searched for valve seal problems here but couldn't find any mentioned. Any ideas of what it might be and what tests to do?

DCJosh

Have you tried to take the oil filler cap off while the engine is idling? From what I understand, if it is impossible to take off, it is a sure sign that the AOS is bad.

bud22405

Blue smoke is from both exhausts and I did just oil change 1 month prior to Mobil Extended Synthetic 5-30W.

alpine003

This is not an approved oil afaik.

bud22405

Maybe a 1-4 second puff of white smoke before this AOS change-out.

bud22405

That oil would make that much difference? I'm talking 10 secs blue smoke instead of previous 2-3 seconds of white smoke that I assumed was primarily moisture. OK, it's worth a try.

Also how much oil fill tube vacuum is too much...any vacuum whatsoever? It is very slight but noticeable.

DCJosh

From what I have read, if it is the AOS, the oil cap is near impossible to take off.

alpine003

If you just got it serviced, I would take it back to your mechanic. Sounds like AOS wasn't installed 100% or engine wasn't cleaned out.

How many miles have you put on it since it got serviced?

bud22405

I've put just 100 miles on it.

Hurdigurdiman

IMHO That mechanic saw you coming. You spend almost three and a half grand and you get the car back and it's still smoking. Did you not test drive it before handing out a check for so much money. Obviously not. Take it back and create hell. At that price he should have dropped the engine and stripped it down... dammit. (special manometer tool to test for defective AOS) my ****.

Sneaky Pete

5-30 is tooooooooo thin. Change it to 5-40. I would also take it back to who touched it last.

mcbit

Valve stem seal leaks generally manifest themselves on a hot engine which has been idling for a while, such as pulling away after being stopped at traffic lights for a couple of minutes.

+1 on 5w30 not being the best choice of oil.

bud22405

Think I'll change to 0-30W Mobile synthetic?

Sneaky Pete

Bud.........our cars like the 5-40 weights. I would stay away from M1 unless you like that buttery stuff in your oil fill tube.

bud22405

ok, thanks for the tip...5-40 it is !