yfz450guy

today i was towing up a grade and noticed that the the temp gauge was hot so i turned off the a/c and backed her down a bit. then the temp gauge dropped to about 120 for quite a while and slowly came back up to normal. engine souned fine and no loss of power. but had perinoid the rest of the day.
any thoughts?
thanks.

yfz450guy

anyone have any input on this?

bulabula

I had a bad thermostat do that on a car of mine. Is your t-stat original?

yfz450guy

no, the t-stat was replaced about 2 months ago. sending unit?

bulabula

Could be the sending unit, or it could be a bad thermostat.

One way to accurately read the temp is hit the stat cover with an IR themometer and read it directly.

Some other things to check: Radiator isn't plugged? Airflow isn't plugged? Fan clutch is working ok?

yfz450guy

come to think of it. the fan does seem like it is running more than normal. how do you check the fan clutch?

WestTN

If the fan is running more than usual for the conditions, then you are running hotter. Have you moved the vent bottle? Did you clean the radiator of all the oil and dirt fron the vent bottle?

yfz450guy

no, the vent bottle is still in the oem location. the radiator and such was cleaned when the motor was swapped out a couple months ago. it has been fine since that day. i am leaning on a faulty sending unit or t-stat or fan clutch. heck i dunno.

2500Ram

Just for a comparison, my 02 likes to use the fan clutch ALOT with the air conditioning running. If the air is off it will never engauge unless I'm pulling a trailer up a grade then it does it's job and cools it back down to less than 190* in a hurry. No help on the 120* drop though but the fan running more now I'll say normal if the AC is running.