Overheating RTV900

[Duckhunter]

This past weekend we did some trail riding with the RTV900 bought in June of 2007. On any hill climb the temp gauge would go up to almost in the red but come down to 3/4 the way over on flat roads. Upon looking, the cooling fan is NOT coming on. In the summer when idling I hear the fan come on occasionally. Now there is no fan at all when almost in the hot zone.
I checked fuses, wiring connectors etc... Any ideas or previous history with this problem?
Great machine with no major issues so far except a scraping rotational sound from under the front end. Any ideas on that one?

 

[Eagleview]

Now there is no fan at all when almost in the hot zone.

Great machine with no major issues so far except a scraping rotational sound from under the front end. Any ideas on that one?

Crook fan motor bearings , damaged fan blades , stick in fan causing both problems ?

 

[SnowRidge]

There should be a thermostatic switch somewhere. It may be defective or stuck. If it has only two contacts (or one plus ground), try shorting around it. The fan should come on indicating the switch is the problem.

I have also seen a similar problem caused by low coolant level.

These are generic suggestions. I don't have any direct experience on the RTV900.

 

[Wayne_H]

Are you sure the fan is not coming on? There are two fans on the 900, one is electric near the radiator, and one is on the enigne, belt drive. My 900 the temp ALWAYS goes almost to the red, then the fan comes on and it drops to 3/4 or so. I have checked it myself with a temp probe and it is not over heating, and the dealer checked it also. I'll bet is is not overheating, unless you smell something or see signs of overheating.

wayne

 

[Duckhunter]

It does smell hot and the fan spins freely with no obstructions. When I say close to hot, it is a needle width away from the red zone. The electric fan is not coming on but has in the past with the temp gauge lower than it has been.
I was hoping to find out where the temp sensor was so I could check for unplugged wire or something simple. It only has 155 hours with no abuse.

Thanks for the replies...

 

[Nwood]

http://www.tractorbynet.com/forums/...-temp-gauge-problem-794434-763011-coolant.jpg

 

[pappy19]

I noticed that when I took out the screen in my mufler, the engine temps dropped and it ran better. Also, the snorkel air cleaner makes the engine run some cooler as well.

 

[TWO GUNS]

I know you have done this, but gotta say it.... Check the water level, pull out the protective screen and wash out the flums of the radiator really good.
Few months ago, keep looking at the screen, and it really looked clean, THEN, for some reason, I decided to remove, and dammmm ~~ about 20% of the bottom of radiator was clogged up with dirt and mud. Don't ask how one could not see it, but couldn't unless the screen was removed.
check the thermostatic switch on the fan motor ~~~~
Raise bed, and wash out radiator backwards !!!!

 

[Jason537]

You want a quick way to check the radiator fan, pull the wire off the sending unit at the thermostat housing and ground it, if the fan comes on the your wiring is fine.

The gauge has no affect on the electric fan as they are wired separately.

 

[arkansasdelta]

I've had my Kubota 900 for 6 or 7 years and usually have problems with it overheating when I'm towing any implement with some drag. I talked with a buddy in sales who told me the heat from the hydrostatic motor combined with any impediments to the radiator are a continual problem with Kubota RTVs. He said even some of the newer models with bigger radiators have the same problem due mainly to the heat from the hydrostatic pump. If I'm in grass or vegetation with light fluffy, seed heads, it will heat up quick if you don't keep the screen clean. I love my 900 and the overheating is the only shortcoming for me. I'm open to any ideas on how to better fight the heat!