I was warned, and upon further inspection one of my cast aluminum thermostat housings on my 575scis......SHOT. The caps are good but the actual housing that mounts to the front of the blower is shot.

I have searched extensively for some kind of aftermarket replacement that is a lower price than the $1300 that merc wants for a cast alum that doesn't last, and one that is beter built


It seems this is a known problem with an unknown solution. I know CMI had something at one time but that is no longer on their site or current catalog.

Has anyone made their own solution to the problem?

I hate to bring this up but if the thermostat housing is that bad I would remove the intake and inspect the water ports they may be just as bad if so water can get into the oil, just saying....

They are coming off as well, engines are out for head gaskets.

Intakes are a relatively easy fix if they have problems. Thanks for the heads up

Mine have 160 hours since they were off. Most of my boating is fresh water but I do hit salt often enough. What have been typical life spans?