I have had a thermostat stick open and I didn't notice and had an overheating problem. Being "stuck" open, is better than being stuck closed. For the reason I mentioned above however, if open and disregarded (like I did years ago),..the coolant doesn't stay long enough in the radiator to cool down and gets hotter and hotter and finally,...BOOM.

I will take the advice and get the factory. I have to go by there (dealer) anyway to see if they are going to honor an E22 recall notice that previous owners never had taken care of. (Found out on the newly obtained build sheet.)

 

Check out their website. Maybe something there will shed some light.

 

If that were the case (a "stuck open" t-stat), wouldn't that also mean that coolant doesn't stay long enough in the motor to heat up? If/when the t-stat is wide/stuck open, the water pump and engine rpm control how fast or slow coolant flows thru both the rad and motor. With a wide/stuck open t-stat, coolant won't flow too fast in one place and too slow in another.

 

The MotoRad web site? I'm still looking for the "guaranteed to open" guarantee. I did notice the trick photography with the t-stat on the left.

 

I know this sounds elementary, but it takes just a few minutes for the engine to get hot,...takes hours for it to cool down. An instant style water heater will continue to give hot water as long as you have power. A water cooler (fountain), will only give the cold water stored in it's tank, it can't be continuous. Hot-fast, Cold-slow.

 

Sorry, but TJWalker's statement is incorrect. All OEM t-stats gradually open when the engine gets close to the opening temperature of the t-stat and reach full open at it's rates opening temperatur. When a OEM t-stat fails, it fails closed. The spring within the t-stat fails to retract the diapham/disc to open the channel allowing the hot water from the block to flow causing a boil over. Fail safe t-stats fail in the open position. Just a word of advice, stat away from high flow t-stats, they are prone to hanging up and will fail on the trail. Also, don't for get when you do install your new t-stat to place the vent hole in the 12:00 o-clock position to prevent an air lock.

 

The t-stat is ever so slightly open at it's rated temp......it's wide open at approx 15 degrees above it's designated open temp. 180F t-stat closed at 180 and wide open at 195. It "hovers" very slowly in an infinite number of positions between closed and wide open and the approx 15 degree coolant temp variation.

 

Don't use a fail-safe thermostat. They tend to stay stuck open if temps run on the hot side. This means if you are out wheeling in sand for a few minutes or towing a trailer your truck is going to run a little hot and the thermostat will be stuck open. I highly doubt you want to keep replacing t-stats if your temps run a little hot. It is very rare for a quality thermostat to get stuck closed. I wouldn't worry about that.

 

x2. I just replaced a 3 month old "fail-safe" unit because it got a little warm in traffic and stuck open. It's a mechanical lock so the stat has to be replaced. ~ HOWEVER ~ I got a std $8.99 unit at Autozone and I don't like this one either. It seems to stay hard closed till 210, then opens and drops to 160, then repeats the cycle.

What brand of t-stat is the best and most stable?

 

Factory part number 83501426. I've had stant Super-Stats opening too early. Three of them. Takes forever for the heater to blow warm. Factory stat now and it warms up real quick.

 

Test the t-stat....see pics above. It should open slowly/smoothly. 50 degree sudden coolant temp drop ain't right.

 

Factory stats result in the most "stable" operating temperature.

That + their reliability = PURCHASE