I have a 1995 Volvo 3.0 L (omc cobra drive). Last fall when winterizing (draining all lines rather than filling with antifreeze) I found a couple good size pieces of rubber impeller in the hose between the water pump and T-stat housing. So this spring I replaced the impeller and, while at it, thought I'd replace the T-stat and see if there are any more impeller chunks. Well, I found the impeller looked perfect (2 years old), so it was likely from an older impeller (this is the first time I replaced it myself, the other shops must not have seen these pieces or cleaned it out). Anyway, when I pulled the thermostat housing (also first time doing this myself) I found that the T-stat was upside down. Not realizing it was upside down, I put the new one in (and gaskets) exactly how I found it and put it back together. It was then that I saw the parts diagram that I had printed out when I ordered the T-stat showing how the T-stat goes in (spring down, pointed side up). Mine was definitely in there upside down (spring up) according to the Volvo diagram. With all the hoses, I'm not sure how the flow runs other than from the water pump to T-stat housing, but it makes no sense to me for the T-stat to be upside down (unless the drawing is wrong). Last 2 years (running with T-stat like this since replaced at a shop) it ran fine with the temp never getting above 160-180 on my gauge. Did the prior shop that put it in upside down know a "trick" - I'm tempted to leave it since it ran fine. Any thoughts on why they had it upside down (I believe this is a competent shop that did these repairs, they found something else that a prior shop could not). Thanks!
