Would very much appreciate any advice on my brother's volvo...(Sorry for the long post)

Its an 88 Dl with about 185K. The oil filter has been hitting the inside of the engine compartment even though its stock and should fit perfectly. You can even feel it when you accelerate, with the thumping getting faster and faster as the RPM goes up. I think its the engine mounts that have gone bad but I have never dealt with mounts before so I can't really be sure.

If it is the engine mounts, is it a hard job to do? (I would do the work...I'm the 'mechanically inclined' one of the family) I've looked at the FAQ for the 700 but I don't know how relavent it is to the 200 series. I don't have very good tools, so I've thought about simply getting it into the shop, but I'm afraid that the bill would be more than the worth of the car (Does anyone have any previous experiences with this?)

Also though about trying to put in a shorter oil filter, and squeezing a year or two more out of the engine mounts, but not sure if there is a good oil filter shorter than stock.

Any advice/info will be much appreciated. Thx!