Wrong Thermostat?????

[21270]

I have a 93 merc 4.3 with a full closed system on it, it has the 160 degree thermostat that came with kit. I was talking to a boat mechanic that deals in Merc's, he say's that merc has done away with the 160 thermostat for closed systems and suggests that people stay with the 140 thermostat. Has anybody heard of this???

 

[Boomyal]

Re: Wrong Thermostat?????

Closed as in running on ethylene glycol? I think your mechanic is nuts. If that is not an electronic fuel injections system, I'd run a 180 deg stat. 140/160 was a compromise to keep salt from plating out inside the engine. Ideal adiabatic combustion chamber efficiency will not occur until you hit 180. Two other nice things about a closed cooling system is you can run a more efficient thermostat and you isolate the block and cylinders from a contuinual extreme variation in coolant temperatures, ie 55/70 deg to 140/160 deg. as the thermostat opens and closes.

 

[mercrewser]

Re: Wrong Thermostat?????

Ask him why and then tell us his response. Hotter t-stat is better. Raw water cooled engines have to have cooler t-stat, making them less efficient.

 

[Don S]

Re: Wrong Thermostat?????

I don't remember seeing any service bulletins about it, or hearing anything from Tech Service. If anything, they are getting away from the 140° thermostats on the newer engines. The new raw water cooled 4.3's run a 160 while the ones with the closed cooling call for a 170° stat.<br />Have them show you the informtion about the thermostat. I would be interested in where that information is coming from.

 

[21270]

Re: Wrong Thermostat?????

He said this is done to keep the exhaust manifolds a little cooler.

 

[Don S]

Re: Wrong Thermostat?????

Bull S**T<br /><br />The thermostat has nothing to do with the manifolds.

 

[Reel Poor]

Re: Wrong Thermostat?????

He just claims to be a merc mechanic. Sounds to me like he just works on em. <br /><br />Time to find a new tech. Before he screws up something on your rig.

 

[21270]

Re: Wrong Thermostat?????

Maybe he was spouting off on what he considers the right way is, or how he would do it. I will ask where he got this information and if i could have a copy. When I told him I was running NGK BR6FS plugs in it, he stated that Merc only uses the Champion plugs because the porcelain inside the plug extends past the threads, which keeps the 4.3 running smooth. The NGK porcelain is tucked below the threads which causes poor performance. I put my trust in the answers I receive here. Back to a question that was asked at the beginning, my motor is not fuel injected and it is run with antifreeze. Thank You!!

 

[mercrewser]

Re: Wrong Thermostat?????

It doesnt really matter, but a hotter t-stat would be better.

 

[Don S]

Re: Wrong Thermostat?????

When I told him I was running NGK BR6FS plugs in it, he stated that Merc only uses the Champion plugs because the porcelain inside the plug extends past the threads, which keeps the 4.3 running smooth.

No doubt in my mind anymore. You need to find a new mechanic.

 

[21270]

Re: Wrong Thermostat?????

Yes Don s, it is time for a new mechanic!!!!!!<br />Thanks goes out to everyone!!!