About 20 000 km (13 000 miles) ago I switched to Mobil 1 from dyno. I have done two other Mobil 1 changes since then. The engine is getting noisier (this also happened with our other car after a switch to a synthetic) and the engine is eating Mobil 1 at a rate of 1L per 2000 km (1 quart per 1300 miles). Before the switch the engine was quieter and there was no oil consumption. Also, in Canada, Mobil 1 is about three times as expensive as dino. I am thinking of going back to dino and keeping the change interval at 5000 km (3000 miles). The questions is: What are the warning signs that the engine is developing the sticky valve problem? How was this problem overcome in the newer cars?

92-960, 195 000 km (121 000 miles)

with this mileage I would try synthetic oil but 5W40 or 0W40.
here in Europe all my volvo friends using 5W40 or 0W40 and it is even not easy to buy 0W30 oil. from my point of view 30 is not enough. higer visco in your case should help

regards,
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Gregski; Volvo V90 '97 B6304FS2 AW3043 95kkm

In defense of Mobil 1, unlikely the oil itself is the problem for consumption. If you are blowing (no leaks) 1 quart per 1300 miles this is still within normal.

Do switch back to a good dino, such as Shell Rotello or Chevron Delo and see what happens to noise. Mobil 1 is NOT the best at high temp. viscosity.

Sticky valves? Noise, hard starting, if at the valve/seat interface low compression numbers/leak down % high out exhaust....

Not sure it's 100% fixed in any white engines, but I think the mechanism to spin valves in seats works better - hence the need for you to do the occasional "Italian tune-up"...

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www.fidalgo.net/~brook4

What viscosity are you using?

10w-30