What I am about to suggest is naughty. I worked many years at a Buick dealership in Florida during the emissions testing phase. In the early days before dealers could buy their own emissions station. All used cars had to go through a state inspection station. Certain cars were known to fail so the ...

My S80 T6 runs Redline synthetic 5W-30 year round since 2016 or 17 3K oil change. Before that, I always opted for the synthetic dealerships use 5W30 the cooler couple months and 10W30 Summer as Volvo requires for the 2004 2.9 Twin Charged T6 engine. Volvo required via the maintenance schedule 5K oil ...

The squeal is the PCV box it's common on those, but it's on top of the engine, I do believe. I suggest looking at the fuel injectors for the misfire and hard starting. You did say the car sat for years. June

I'm really curious too!!! June

A wet compression test is how to check the rings. Engine cold check compression say it's 90. The/n rem add Engine oil into the still cold cylinder and retest the compression. Say it jumps to 125 you know it's bad rings, say it stays at 90 then it's a valve. If it needs a valve job that's doable. June

How did you determine the #4 cylinder has low compression? Did you do a wet compression test to determine if it's a valve issue or the rings? Did you compression test #3 and #5 to rule out the head gasket? Perhaps scope #4?

To answer your question; I don't believe those engines having problems with ...

Choose the engine that is the same. The 3.0 T6 engine came in three variants. B6304T2, Or B6304T4, and the Polstar B6304T5. I'm quite sure all three use a intercooler? June

FYI; the stick on woodgrain was dealer installed at least in 1998. It was stupid expensive for the time. Volvo of Tampa had added it to the 1998 V70 Cross Country I bought. I refused to accept the car until it was removed. They removed it and the addendum sheet. It wasn't about the money, i thought ...

No. Select a car with a standard transmission. The faulty 01 transmissions stemmed from a bad stop/neutral program. Volvo updated those cars twenty years ago. June

Glad you found us! I look forward to seeing pictures of your Volvo. June