If you are replacing the tensioner then it will come compressed and you don't need to compress it. Unless you don't line up the marks properly before you pull the pin . fcp prices 27 t-belt 125 genuine volvo t-belt tensioner, hydraulic 48 t-belt tensioner roller 48 idler arm roller 49 water pump Hepu 297 total you can save a few bucks with eEuroparts.com, or you can ask fcp for the eBaY special (240 for everything but the water pump), but you get the idea, it is a $300 job to get new everything.