View Full Version : T-stat what is everyone using?

08-26-2012, 10:02 AM
I have a 165 degree t-stat installed the motor runs at a tad under 170 and after hard runs a tad over 170 probably 180-190 is that too high or is it okay ford 5.0 ho

my 16 had no t-stat and ran 140 and after hard runs would jump to 200 then drop back down to 140 after some time at idle

08-26-2012, 10:57 AM
I use a 140* thermostat because I run in salt water and have been told that above that the salt acts badly with the iron. After a hard run, it'll get to maybe 160* for less than a minute as the thermostat adjusts for the lower water flow.

08-26-2012, 12:39 PM
"in the day" most all older marine engines used~
160* in fresh water
140* in salt water

Your 165* T-stat seems to be running slightly high~~~But these things are not very accurate anyway.

I usually test new T-stat units in a pan of water on the stove with a candy thermometer beore installing them .

The Robertshaw units seem to flow much more water than the Stant brand T-stats as they have a wider valve opening and thus seem to keep engine temps from spiking when slowing down after a hard run.

Your 165* T-stat should be OK in the old Ford.

John C in PA
08-26-2012, 03:10 PM
Matty, my '92 302HO always runs 125 degrees at no wake speed, 125 deg for early Spring cruising (colder lake temp), 130 deg during Summer cruising and 135-140 deg after a hard WOT run. Then returns to normal soon after. I havent replaced the t-stat yet so I don't know it's rating.

This winter I'm installing a 160 deg EMP Stewart t-stat predrilled with 3 bypass holes (so there is always some waterflow and less changes in the cooling system temp).

HTH, John C

John C in PA
08-27-2012, 09:58 PM
Got mine here: http://www.jegs.com/i/Stewart-Components/935/300/10002/-1?parentProductId=761639

John C

08-28-2012, 07:25 AM
gonna see how it runs up in lk george much different water temps up there .