Volvo Repair: 2000 volvo s40 1.9 turbo, oil filler cap, automatic transmission fluid

Question
just bought  this for my 16 year old son...98k miles, runs like a missile, and sounds like a rolex. at about 600 rpm, engine lite eluminates intermittently. a touch on the rpms, no lite. engine lite is allways eluminated. dealer scopes it and says $4500 to dismantle and clean all of the oil passages/galleries... all sludged up!!!! ran my finger at the oil filler cap area.... very small crystelized dark particles. oil cartridge element quite clean but at the bottom of the cartridge housing... hard black stuff about two tablespoons. pep boys suggested an engine power flush with their machine 40 psi for 30 minutes. what do you suggest? remember, i said it preforms beautifully!! synthetic oil ok? thanking you.
leon

Answer
I don't know if that is a good idea or not.  If it was any old car I would say go for it but since this car is a turbo it is very sensitive to oil condition and I don't know how abrasive this process is on the engine.  We don't have such a machine at our dealership.  There are two things you can try on your own first if you choose.

1)  there are oil cleaning agents available that you put in the oil when the car is heated up, and you let it run for a short period of time at idle.  It has alot of detergents in it and a thinning agent so more of the deposits can be drained out with a normal oil change.

2)  drain the oil and put in automatic transmission fluid instead.  ATF had more than 10X the amount of detergents that motor oil does.  It does not coat engine parts as well though so as long as the ATF is still in the engine DO NOT REV IT OR DRIVE IT.  IDLE ONLY!!  That part is very important.  After its sat in the driveway for about a half an hour or so drain that out and fill back up with normal motor oil.  You'll have to put in a new filter for the ATF and then another new filter for the oil.  

Other than that I'd go with one of the other two options that have been presented to you.  Every time you do a filter on that car remember to replace the O-ring on the casing, and to replace the crush washer on the drain plug everytime you take that off.  Hope that helps.

James