140 vs 160 thermostat

[Mkos1980]

Why was a change made over from the 140 to the 160 stat in the later year mercruisers? My boats a 90 and came with a 140 stat, I've been running it but it seems that with the cold Water here now I get alot of condensation. Nothing really just driving around but give some WOT runs for ahwile and getting the oil super hot and the super cold water, I'm seeing alot of water vapor and some white residue on the upper inside of the vave covers. Go back to driving normal and it all goes away. Would a hotter stat minimize this because the block would be hotter?

After the heads cam and intake upgrade I said man, I hope I'm not getting water into the motor somehow, but I blocked everything off and pressurized it and the entire assembly held 20lbs for an hour straight. I figure that was a sufficiant test.

 

[waterone1@aol.com]

Re: 140 vs 160 thermostat

I have to ask you a question, based on your post. When you are doing wide open throttle runs, is your engine temp climbing ? If so, what is the hottest you have seen it ?

 

[Mkos1980]

Re: 140 vs 160 thermostat

With a 140 stat , the highest its ever been has been 150 and that was after a good couple minute 5,000RPM Run.

 

[chiefalen]

Re: 140 vs 160 thermostat

Normal. Leave it alone.

 

[Don S]

Re: 140 vs 160 thermostat

The only reason they have gone to the 160? stat in newer models is to get the engine temp up some more for cleaner burning of the fuel to make the EPA happy. If a raw water cooled engine is run in salt or brackish water the salt has a tendancy to build up faster and heavier with the higher temps.
Use of Salt Away or similar product can eliminate that build up if used to flush the engine after each use.