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View Full Version : '89 351 Indmar constantly 140 degrees


homer12
06-15-2013, 09:18 PM
My engine in '89 Tristar never gets much past 140 to 145 deg after running constantly at about 2500 rpm's. Does that seem normal for this engine? I thought I should be running closer to 160 constantly? If that seems cold, I'm guessing start by checking gauge, then sensor, then thermostats, right...

slushpup
06-15-2013, 10:04 PM
Dumb question but, a 351 will run arond 140 with no T-stat,Are you sure it's in there? I Forgot one season To replace mine, Boat ran cool and annoyed me till found it in the glove box.

j.mccreight@hotmail.com
06-16-2013, 09:35 AM
That's a true statement an open or missing thermostat will operate a 351w at 140 degrees.
First I would check the thermostat, that's the easiest and cheapest item.

Engine Nut
06-16-2013, 10:22 AM
My engine in '89 Tristar never gets much past 140 to 145 deg after running constantly at about 2500 rpm's. Does that seem normal for this engine? I thought I should be running closer to 160 constantly? If that seems cold, I'm guessing start by checking gauge, then sensor, then thermostats, right...

The 351 has a 140 thermostat. If you are running at 140-145 you are right where you belong.

Dino Don
06-16-2013, 10:25 AM
Mine ran that way until I replaced it and now it's at 160. Engines can run too cool as well as too hot.

homer12
06-16-2013, 12:46 PM
Well, I've never touched the thermostat so probably time to check. This would be the one on top of the water pump right? Is it a 143 or 160 t-stat to be sure?

j.mccreight@hotmail.com
06-16-2013, 04:13 PM
Well, I've never touched the thermostat so probably time to check. This would be the one on top of the water pump right? Is it a 143 or 160 t-stat to be sure?

^ according to engine nut it should have a 140 thermostat. I ran my 351w without a t-stat for a summer (mistake unknown to me when I bought my boat) and it ran at 140. I installed a 160 thermostat from http://www.bakesonline.com/detail.aspx?ID=844 and it operates right at 160-165 on my gauges.

homer12
06-16-2013, 07:36 PM
Then any harm in running 140deg? I don't understand what damage or harm could be done by running a cooler engine. Looks like according to Bakes it may just be more efficient around 160deg

j.mccreight@hotmail.com
06-16-2013, 07:40 PM
Then any harm in running 140deg? I don't understand what damage or harm could be done by running a cooler engine. Looks like according to Bakes it may just be more efficient around 160deg

Imo no problem, only issue I could see is if a heater is in play it probably won't work properly with a damaged or missing thermostat.

j.mccreight@hotmail.com
06-17-2013, 02:12 PM
Well, I've never touched the thermostat so probably time to check. This would be the one on top of the water pump right? Is it a 143 or 160 t-stat to be sure?

Location of thermostat...

homer12
06-17-2013, 02:35 PM
Thanks, mccreight! That's super easy to check. Would you recommend I have a gasket if I'm going to pull the top off and check it?

thatsmrmastercraft
06-17-2013, 03:20 PM
The existing gasket never survives to be used again. The gasket is cheap, so get one with the new stat, and apply a little silicone to both sides of the gasket to keep it in place and prevent any leaks. And don't over-tighten the housing.