Review on Dorman 902 5152 Coolant Thermostat Assembly by Tim Hodzic

Good replacement for the original Volvo thermostat housing: All fittings, electrical and mechanical, are the same. The whole process is a colossal PIA (removing the timing belt cover, removing the serpentine belt, not enough room for big hands with wrenches, etc.), but it can easily be performed by a home mechanic. Before assembling, pay attention to the position of the outlet on the rim of the thermostat: remove this side of the housing and make sure the outlet is facing up (1200). I then filled the body and gaskets on both sides with silicone before installing the entire unit. I couldn't find the torque specs for the bolts, so I tightened them until hard. The largest PIA gets the bottom right nut/bolt (forget which ones) where the body attaches to the engine. I believe it's a 10mm nut and a crowfoot wrench or flex drive would do. My original had 4 mounting holes, the Dorman model had 3, eliminating the need for the bottom left corner but ensuring a secure fit. I did not drain the system but covered the generator before disconnecting the hoses. This is what the repair manual (Haynes) calls a "vertical" thermostat.