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I'm having issues and looking for some help. Yesterday on a semi slow ride in the woods My 800XP went into limp mode and I immediately noticed that the temp was at 234 and the fan was running, I quickly killed the engine. Then had radiator fluid squirting from the reserve reservoir. I was quite a ways from the house so I decided to let cool fully then ride fast to the house in order to get maximum air flow through the Ranger and hopefully get back home, and that I did. But on the ride home everything was working as it should, fan cycling and cooling like it should. So I thought "the thermostat is sticking" Ill just get another one and stick in it, because this happened a few months ago also, but hasn't happened since until yesterday. Now after I read some post that pertain to parts of this situation I'm not really sure if the thermostat is sticking or not. Then when I was going to order a new thermostat I notice there is a thermister beside the thermostat....is this the culprit???? Then I read about the radiator cap going out on some Ranger's.......how do you check that to see if its bad????:confused::confused::confused: I don't want to order a $25 dollar cap just to see if that's the problem????

Now Im not sure without some of the expertise on here exactly what to replace first....:distress: So if anyone had this issue and could offer me some suggestions I would greatly appreciate it!
 

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Doesn't sound like the thermostat since all is well when getting good air flow across radiator and doesn't sound like a radiator cap issue. I don't know what a thermister is. There are several posts on here discussing the fan relay going bad and causing erratic fan cycling - sounds like your problem.
 

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The thermistor is the temp transmitter that tells the fan when to come on and when to shut off. You can pressure test the cap, (any good radiator shop can do this for you) to see if it is bad. How dirty is your radiator, I would start there making sure it is clean, next in terms of troubleshooting would be the cap, then the fan relay if it has one, then the thermistor, then thermostat, then fan unit itself.

I always leave my gauge on water temp, so I can see what is going on (when it starts, when it stops, how quick it is cycling, ect.) If your fan is coming on at 204 and shutting off at 192, I would say the thermistor is good and working correctly. It may be a wiring issue, and possibly a fan relay going bad.
 

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Sounds like a weak circuit breaker to me. Intermittent operation. If anyone is in need of a good 13psi replacement radiator cap for the Po, for $7.20, here it is............Radiator Cap OE Type Stant 10227 | eBay
 

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Discussion Starter #5
OK I thought I had found the problem, now I have narrowed it down. The fan comes on as it should (204F) for 4-5-6 cycles then as the machine really heats up after 15 min or so of riding the fan wont come on till 235+ which is when the overheating light comes on. the the fan is cooling it back to 204 and shutting off. Im confused now for sure. Riding just short distances its fine, longer than 15 min and is is overheating, but the fan is still cycling????? Is this the thermister???? or is it a fan relay???? If its a fan relay could someone point that out to me? Thank you again for the help!
 

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A relay is $45 and a fan motor assembly is $236. The bike takes 4 relays, so I would start with swapping a non essential relay for the fan and see what that gets you. If it continues to do it, it is the fan motor assembly. Had this same scenario happen on an 800 RZR S.
 

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I just had the same problem for the second time in three months..was riding around some fields at a slow pace and the fan was cycling fine (on at 204 and off at 192)..then I noticed the fan came on at 204 and the temp continued to climb...luckily I was back home when it done it this time. I got it parked and it was switched off at 220 degrees. After switching it off, coolant began shooting out of the reserve reservor. Both times this has happened, after the engine cools, I refill the radiator and reserve and everything seems to run normal
 

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I have been told that it is not good to shut down an engine while its trying to cool with the fan on.. I wonder if the coolant shot out cause the temp kept rising with no more circulation? Sometimes mine runs up to 208 but will go back down to 194_192 and continue to cycle on an off...
 

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The thermistor is the temp transmitter that tells the fan when to come on and when to shut off. You can pressure test the cap, (any good radiator shop can do this for you) to see if it is bad. How dirty is your radiator, I would start there making sure it is clean, next in terms of troubleshooting would be the cap, then the fan relay if it has one, then the thermistor, then thermostat, then fan unit itself.

I always leave my gauge on water temp, so I can see what is going on (when it starts, when it stops, how quick it is cycling, ect.) If your fan is coming on at 204 and shutting off at 192, I would say the thermistor is good and working correctly. It may be a wiring issue, and possibly a fan relay going bad.
When did Polaris start including the water temp on the gauge?
 

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OK I thought I had found the problem, now I have narrowed it down. The fan comes on as it should (204F) for 4-5-6 cycles then as the machine really heats up after 15 min or so of riding the fan wont come on till 235+ which is when the overheating light comes on. the the fan is cooling it back to 204 and shutting off. Im confused now for sure. Riding just short distances its fine, longer than 15 min and is is overheating, but the fan is still cycling????? Is this the thermister???? or is it a fan relay???? If its a fan relay could someone point that out to me? Thank you again for the help!
" after 15 min or so of riding the fan wont come on till 235+" Brad, That is exactly what happens when the c. breaker is not functioning properly. They are garbage and will not cycle properly once they get hot.
 

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I have been told that it is not good to shut down an engine while its trying to cool with the fan on.. I wonder if the coolant shot out cause the temp kept rising with no more circulation? Sometimes mine runs up to 208 but will go back down to 194_192 and continue to cycle on an off...
The reason I switched off this time while still hot is because the first time it happened I wasn't watching the temp gauge and it actually cut off with me. When it cut off I looked at the gauge and it was at some 260 degrees and was dumping coolant from the reserve resorvor. Again, I let it cool, refilled the radiator and was able to get it home. Continued to drive over the next several months while keeping an eye on temp and it was running normal again (Fan on at 204 and off at 192) up until this incident. I've driven around the house since, and it appears to be seeping coolant while the engine is running and it will run fine until it runs out. Just can't figure out the problem..
 

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and just as a note, No check engine light (except when it cut off, but cleared when cool) and no hard riding
 

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and just as a note, No check engine light (except when it cut off, but cleared when cool) and no hard riding
QA, have you bled the air from the cooling system after these refills ?
 

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If coolant is "seeping out" does that mean your water pump tattle tale is leaking indicating you need a new water pump, or is coolant leaking from somewhere else?
 
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