later

have a friend that has a 97 4.3 efi with a bravo three out drive, water tempeture goes up to 185-190 then will drop back down to 120 then a few minutes later rises back up the 185-190 and then will drop back down to 120, this is after he replaced the seawater pump because of a bad impeller, he then replaced the circulating pump and thermostat, any ideas.
also does any one have a serpintine belt diagram for this motor to make sure he has the belt on properly.

thanks in advance
later

handfulz28

Somethings wrong in the t-stat housing or possibly the water flow. I had the same thing happening and ended up putting a new housing in; fixed it.

jhiguy377

indeed that kind of fluctuation would seem to be thermostat based. good luck - jeff

rdoactive

I've seen similar problems caused by a bad head gasket. A quick check of the plugs will rule that out.

1BIGJIM

iTrader: (1)

bad impeller, he then replaced the circulating pump and thermostat, any ideas.

Did you back flush the system to get all the little rubber impeller parts out? I am willing to bet that is your problem