Hi Eastbay,

$9500 estimate? Yikes! Did you get that estimate at Mafia Motors?
Hopefully you went somewhere else for a second opinion, before you suffered
cardiac arrest.
You might post that estimate so that we can all be amused.

Did you get the service records from the previous owner?
You'll want to know when the timing belt was replaced, also you'll want to
get the mileage off of the computer and see if it's the same as the odometer.

Someone else can comment if they have a good idea for an engine flush.

Dyno oil is poison in the Volvo white block engines, and dyno oil clogs up the EGR and cylinder head too with a hard crusty crap. The clogged EGR can raise crankcase pressure causing failed engine seals. Plugged cylinder head oil galleries are bad news also.

When I went back to the 940 B230FT I switched to Full synthetic oil, and it is cleaning out this engine gradually. So my suggestion is to decide on what flush or treatment you will do, followed by using only Full synthetic oil.

Good luck, Bill