Thermostat removal ??

atbspinner · **Joined:** Mon Apr 25, 2011 7:07 pm **Posts:** 38

So I dropped off the H170 to have the oils changed and impeller replaced. This is the first time to use this mechanic.
He recommended that I remove the thermostat and not replace it. I have not had any issues with overheating. He
said it is one less thing to worry about in the cooling system as far as blocking the flow of water. Does this sound
like good advise? I don't know much about the purpose of the thing but I'm sure it is there for a reason.

Paul I. · **Posted:** Wed Apr 17, 2013 2:45 pm

I would "why" not "that its one thing less...." I would leave it in! It helps the engine to maintain operating temp.

psusound · **Joined:** Sat Feb 04, 2012 4:08 pm **Posts:** 69

Cant hurt to replace every year, easy maintenance item. You want to keep it in. But I would replace it every year, if not every other year.

rpengr · **Posted:** Wed Apr 17, 2013 3:02 pm

In warmer climates (water temps 75F or more), it will run OK without the thermostat, but you are better off to leave it in. In a pinch, you can make it back to port without the thermostat.

NiagaraChillin · **Posted:** Wed Apr 17, 2013 3:40 pm

I would find a new mechanic. Marine engines are designed to run at a certain temp, usually 160-180. Running without a T-Stat will play havoc with your fuel consumption, not to mention running a "cold" engine prevents certain oils from doing their job. Oil works best at operating temperature.

T-Stats are relatively cheap and easy to replace. Keep a spare on the boat, easy to replace even on the water. Unless you boat in salt or brackish water, no need to change every year. Maybe every two years if ya want, but most will last at least 3-5 years.

LouC · **Posted:** Wed Apr 17, 2013 5:00 pm

Funny you should ask, I used to change them yearly and had a collection of 6 old ones. For fun I tested them in a pot of water using an old fashioned automotive thermometer used for checking thermostat function. They all worked pretty much the way they should and these were all used in salt water.

I would not advise running without a 'stat. Marine engines run cool compared to the automotive engines they are based on even with a stat (automotive, stat is 195*, marine, usually 160*). If you remove the stat it may not get over 120* unless you are running on plane. Running cold is not good for engines. In my experience thermostats rarely fail and when they do its sticking open a bit with cool operational temps.

Winter Sux · **Posted:** Wed Apr 17, 2013 5:08 pm

I agree with Niagara! Get a new mechanic. Yours is a misinforming idiot.

Engines are designed to run at a given operating temperature. Without a thermostat, the block and heads will barely warm up at all. Yet the pistons and exhaust valves will get hot from the combustion. When things warm up, they expand.

Cold block and heads = no expansion.
Hot exhaust valves and pistons = expansion.

Result = worn out cylinder walls and exhaust valve guides.

The End.

John :mrgreen:

LouC · **Posted:** Wed Apr 17, 2013 5:09 pm

Funny you should ask, I just tested a few old ones I have as spares that were used in salt water and they all worked fine. I used to replace then every year but now I test it, if it works fine I put it in with a new gasket.

atbspinner · **Joined:** Mon Apr 25, 2011 7:07 pm **Posts:** 38

Thanks for the advise. I called him back as told him to replace the thermostat since it has not been done in at least 2yrs. I will let him
change the fluids and probably not go back. I'm really surprised he offered that suggestion on such an inexpensive part that is obviously
important for protecting any engine. Makes me wonder how many he has taken out.

Walt · **Posted:** Thu Apr 18, 2013 9:03 am

I agree with above statements... new Mechanic... makes you wonder what other corners he cuts without your knowledge. Your engine will run too rich and start fouling plugs. I am still on my 5 yr old t-stat. I have a gauge on my dash that shows cooling water temp. If that starts acting funny, I run on the muffs to flush (Mo lakes/river are silty). If that no worky, I would replace, and have a spare/gaskets ready for the occasion.

ric · **Posted:** Thu Apr 18, 2013 9:44 am

That guy is an idiot. Find a new mechanic.

chrisvs · **Posted:** Fri Apr 19, 2013 8:43 am

Agree with everyone here, find a new mechanic. It is a 5 minute job to change it on the 3.0. 2 bolts and litteraly right in front of you. Heck, You barely even need to bend over to change it!

Had to change mine last season, as it started to stick closed.

www.iFourWinns.com

Thermostat removal ??

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