How ofter do you replace thermostat?

Incaboater

Seaman Apprentice
Joined
Mar 12, 2007
Messages
33
Just curious as to how often you guys replace the thermostats? Is this a bi-yearly thing? Seems like you would not one to break on you as it is hard tell anything is wrong until the engine is on the brink of frying up, at least from what I understand. I understand the impellar is bi-yearly, but I never really hear much about the thermostat.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
Re: How ofter do you replace thermostat?

They are a lot more dependable than most people think. And when they do fail, they usually fail in the open position. Note, I said Usually. But there's nothing wrong with replacing them as often as you feel comfortable. It's only money.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: How ofter do you replace thermostat?

if running in salt , yes.
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: How ofter do you replace thermostat?

Right, and send the old ones to me, I'll think of something to do with them.
 

Incaboater

Seaman Apprentice
Joined
Mar 12, 2007
Messages
33
Re: How ofter do you replace thermostat?

Thanks for the replies, It has only been used in fresh water lakes, though you can pretty much consider some lake around here nuclear waste:^, well the chattahoochee is pretty much a nuclear waste dump river, that place is nasty, so hopefully none of that messes with my equipment, lol.
 

dsujen

Petty Officer 1st Class
Joined
Oct 16, 2004
Messages
252
Re: How ofter do you replace thermostat?

I have an 86 110 hp vro evinrude bubble back. Just put new therms. in it last year. They failed to work after I winterized the boat. I heard you don't even need the therms. and it's a problem solver to leave them out. Any one hear of this before? I don't want to re install if they are going to cause a problem every season. They are very hard to get to. I had to cut an acess panel through the lower engine shroud to work on em. There was a little crud but they worked after I cleaned them off and put a match to them.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,780
Re: How ofter do you replace thermostat?

This subject has been beaten numerous times. Archives has lots of info.

There is an official tester and if you do not have one you can use a pan of slowly heating water with a suitable thermometer immersed to run your own test.

The opening temp (where the baffle comes off it's seat and starts moving) is usually stamped on the pellet......like 120F or 143F for a couple I know.

Slowly heating water to give the stat time to open and follow the temp of the water.

By 20 degrees over I'd imagine that it would be fully open....spring pretty well compressed.

I originally had the concept that none was great since they went for so many years without them, but have since reconsidered and after having had mine fail (shut) and having run the engine for awhile with it out. I replaced it with a new one. This is my second failure and both were frozen shut.

On some V6 engines the upper bank (starboard side on Merc) can run without adequate water if the stats are removed. It runs out the lower one and can't fill up to the level of the upper one at lower engine speeds.

Frequency is up to you. If it looks good....like it is capable of moving properly and and not gungied up, and passes the water test, then why replace it......unless for $10 it just makes you sleep better.

I have had an old one working fine and replaced it (In a car) cause it was old, with a new one, and it failed on the first trip out. So, you just never know.

But modern engines have overtemp alarm systems and that's what they are for.

My 2c

Mark
 
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