Thermostat

Joined
Jul 15, 2006
Messages
45
Age
63
Location
Dayton, Ohio
Bike
2005 ST1300
If the thermostat fails in the open position, what will the water temp indicate? What should a normal reading be versus a reading with a bad thermostat? Thanks.
 
If a thermostat fails open then you should see the temperature rising and falling a little depending on other factors... ambient temperature, fans kicking in, riding speed etc. Normally the bike will take a little longer to warm up and in 'normal' ambient temperatures when moving will probably register below normal... say 2 bars. This is because the coolant can continuously circulate and so the system is too efficient.

Regards,
 
+1 on what Dave said. My thermostat was stuck partially open. Took longer to reach 3 bars (while sitting). After moving, would not hold 3, but dropped to 2. I've seen it drop from 2 to 1, too. Mine would not hold 3 bars at 55 degrees F, which is getting fairly warm.

When I told my dealer about the longer warm up time, he was concerned enough to pull the stat and test it. It was bad (surprise!!). Warranty covered it.
 
Paul Zurawski said:
If the thermostat fails in the open position, what will the water temp indicate? What should a normal reading be versus a reading with a bad thermostat? Thanks.

It will take a little bit longer to reach 3 bars in the warm weather. Most riders don't really notice the effects of a failed thermostat until the weather cools down. Then it really takes a while to get to 3 bars if at all.

Ray
smile04Bikerwheelie.gif
 
If it fails open or partially open, at less than 50 degrees the coolant temp gauge won't get to three bars. It will stay at two or one bars.

Above 50 or 60 degrees, it may be hard to tell if it is sticking open because the guage will reach three bars anyway.
 
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