Easy fix for smoking 850 turbo-DO NOT USE

[billy]

I recently replied to question regarding fixing smoking 850 turbos..I was told that switching to 20W- 50 oil would stop smoking if the valve seals were worn...even with other cautions sent to me..i tried...bragged that it worked..less than 1K miles later...I now have to have timing belt and valves redone...$1,100 and change to get repaired...can't prove that was the cause...but go figure...what's the odds

[fazool]

Timing belt is outside of any oil path and the pulleys, etc are sealed bearings that never see motor oil. So, any failure of the timing belt by itself is unrelated to oil. If the T-belt breaks, the valves will follow but not the other way around.

The argument for using higher viscosity oil around turbos is because of their extreme heat, but at start up the bearings can be oil starved because of the small orifices, so I would recommend against it for those reasons.

If you have leaky valve seats/guides the thicker oil runs down slower - that's the "fix" you were trying for. But, again using the higher viscosity oil at startup makes it run slower (before it warms and thins out) so the small precision passageways (turbo etc) lack proper lubrication

[erikv11]

Agreed, in answer to the question "what are the odds": I would say essentially zero.

Running 20w-50 won't cause a timing belt failure, or a burned valve for that matter (the other common reason heads are re-done on these cars).

If your car has bent valves then paying a shop only $1,100 to fix it seems a very low price, make sure they are using decent quality parts.

[jblackburn]

I would never put 20w-50 in any car built in the last 25 years to begin with.