Engine temp question - 351 king cobra

[mrbell83]

My 1992 351 has been running right around 140 degrees most of the season. Just recently I started noticing that the gauge is now up near the 160-170 range. I have the original OMC service manual and it states that the 350,454,502 motors should have a 140 degree thermostat and the 351 should have a 160. I am assuming that maybe earlier in the season the water wasn't warm enough and thus the engine never really warmed up.

Would I be correct in my assumption? I guess I am just looking for some reassurance.

Thank you,
Chris

 

[QC]

Re: Engine temp question - 351 king cobra

First season with this boat? No info from a complete season before?

Lake water temp should not matter much if the thermostat is not leaking. It might also not be opening all the way now. I'd replace it and test the old one for fun. Also, what's the condition of your pump impeller, when was the last time it was changed? Changing water temp is usually an indicator that should not be ignored

 

[mrbell83]

Re: Engine temp question - 351 king cobra

First season with this boat? No info from a complete season before?

Lake water temp should not matter much if the thermostat is not leaking. It might also not be opening all the way now. I'd replace it and test the old one for fun. Also, what's the condition of your pump impeller, when was the last time it was changed? Changing water temp is usually an indicator that should not be ignored

I bought the boat last fall (October) and the pump was changed then along with the impeller.

The factory manual states that the thermostat should be a 160, I wonder if it was stuck open before and now it is functioning normally? In any event, I will change it. Is it a gasket that you purchase for the housing or do you just put a bead of sealer on?

Edit: Also, If I change the thermostat and the temperature stays the same, what should I look for next?

 

[mrbell83]

Re: Engine temp question - 351 king cobra

When you get the thermostat they usually come with gaskets (usualy several to fit different installations). FYI: Pick one up at the local automotive store, it will save you quite a bit of cash and they are the same thing.

What if the temp stays the same? What should I look for next? Or, should I assume that the old thermostat might have just been stuck at one point if it functions normally after testing.

 

[mrbell83]

Re: Engine temp question - 351 king cobra

Put the new T-stat in and test it. If temp is stable your good to go.

Will do...

Thank you.