Thermostat

[Mitro]

I have a 36' Regal with 2 454 Mercruisers that needs new thermostat's. With my fathers Searays' - 27 & 34', he always bought the 160 degree thermostat, but the guide says to stick with 142 degree. My father is highly recomending to switch to the 160, but our marine store says that is way to high. Does anyone know the pro's con's, dangers of going to 160?

 

[Haut Medoc]

Re: Thermostat

Welcome to iboats .....
Is this a raw water cooled system of a fresh water cooled system?
Generally 160* for F closed systems & 142 for raw water systems........JK

 

[bruceb58]

Re: Thermostat

Newer fuel injected Mercs and Volvos are also going with 160 on raw water cooled engines.

What part is specified for your year/model engine?

 

[Mitro]

Re: Thermostat

Newer fuel injected Mercs and Volvos are also going with 160 on raw water cooled engines.

What part is specified for your year/model engine?

18-3551 is the part # for the 142 degree.

 

[crawdadric]

Re: Thermostat

I have a 1985 Sea Ray SRV300 with dual 5.7L carburetor engines (re-powered in 2003) and the Mercruiser manual requires 160 degree thermostat (raw water cooled). I bought the thermostats from Doug Russell and that was the thermostat listed on his web page for engines with my serial numbers. The thermostat that was actually in there prior to me buying the boat was a 140 degree.

I think the 140 degree stat keeps the engine cool so salt water does not cling to the internals of the engine block and the 160 stat would burn gas more efficiently - IMHO.