Coolant Issue 2020 850 KHAOS

[looper]

My 2020 850 KHAOS, 375 miles will not circulate coolant. When idling, no hoses warm except return line from engine under the thermostat, coolant in bottle remains totally cold, hose to water pump remains totally cold, exchangers totally cold. Any Ideas on where to start?

Thank you!

 

[Winshady]

Is the thermostat not opening? Check the simple stuff first.

 

[looper]

Doesn't matter in this case with the Tstat in the coolant reservoir. With the multi circuit system the the coolant has to end up back in the bottle one way or the other. There is never a point where coolant can't make it back to the reservoir no matter the position of the tStat.

 

[TRS]

Raise the front and tip it to the clutch side with the cap off the bottle or loose. Let the engine warm up. If it’s air locked that should clear the system.
If that doesn’t fix it you have another issue.
We have had to replace a few bottles.

 

[looper]

Will give it a go! How big of a pain is bottle replacement?
Thank you!

 

[looper]

Raise the front and tip it to the clutch side with the cap off the bottle or loose. Let the engine warm up. If it’s air locked that should clear the system.
If that doesn’t fix it you have another issue.
We have had to replace a few bottles.

What was the reason for changing the bottles? Were they stuck in bypass mode?

 

[RHODESIE]

don't these have that stupid plastic drive gear for the water pump shaft now Tony?

 

[looper]

don't these have that stupid plastic drive gear for the water pump shaft now Tony?

Yes they do... Weight savings is one thing but, would rather have stainless in this critical component!

 

[looper]

This is my understanding of how the cooling system works on a 2020 Axys chassis with 850. Ther are basically two states. Thermostat closed or opm. Thermostat closed state. The system is in bypass and circulates coolant from the pump, through cylinders, heads to reserve bottle then direct back to the pump. Thermostat open state. Coolant takes the same initial path but instead of heading directly back to the pump from the reserve bottle, it is passed through the bulkhead and tunnel heat exchangers, then to the reserve bottle, then back to pump. There is a transition time, 10-20 seconds, as the thermostat is actuating, coolant can be routing through both circuits until the thermostat is completely open. What am I missing here?

Thank you,

 

[MTNTK]

This is my understanding of how the cooling system works on a 2020 Axys chassis with 850. Ther are basically two states. Thermostat closed or opm. Thermostat closed state. The system is in bypass and circulates coolant from the pump, through cylinders, heads to reserve bottle then direct back to the pump. Thermostat open state. Coolant takes the same initial path but instead of heading directly back to the pump from the reserve bottle, it is passed through the bulkhead and tunnel heat exchangers, then to the reserve bottle, then back to pump. There is a transition time, 10-20 seconds, as the thermostat is actuating, coolant can be routing through both circuits until the thermostat is completely open. What am I missing here?

Thank you,

Your totally correct about the circulation, albeit the thermostat can stay in a partial open state and "bleed" in cool water to try and maintain the correct coolant temp for the engine. It's not really only an open or closed valve unless the temps rise and fall far enough to fully actuate it. We have seen many failures of the reservoir integrated thermostat since 2019, causing overheating but the cooling water is not circulating. For what it is worth, we have never seen a newer engine with the plastic drive gear for the water pump go bad and fail yet. Polaris moved the thermostat to the bottle because it does prevent vibration from damaging it, but it seems from our experience that they still have a failure rate that is similar to the previous designs. Usually we replace the bottle and then you just have the normal amount of overheating! MTNTK Tunnel Cooler for the Matryx Chassis

 

[looper]

Your totally correct about the circulation, albeit the thermostat can stay in a partial open state and "bleed" in cool water to try and maintain the correct coolant temp for the engine. It's not really only an open or closed valve unless the temps rise and fall far enough to fully actuate it. We have seen many failures of the reservoir integrated thermostat since 2019, causing overheating but the cooling water is not circulating. For what it is worth, we have never seen a newer engine with the plastic drive gear for the water pump go bad and fail yet. Polaris moved the thermostat to the bottle because it does prevent vibration from damaging it, but it seems from our experience that they still have a failure rate that is similar to the previous designs. Usually we replace the bottle and then you just have the normal amount of overheating! MTNTK Tunnel Cooler for the Matryx Chassis

Thank you for all the time you have invested in this issue. I replaced the bottle knowing that it most likely was not going to solve my problem and it didn't. I have had front elevated, the rear elevated and had sled all but upside down all while the engine was running, in hopes of releasing a potential air lock. No luck. The coolant in the bottle doesn't get even remotely warm and the engine will eventually overheat in two to three minutes while idling. Another key fact at the root of this issue is, through a totally boneheaded move on my part, the machine was stuck upside down, with wide open throttle for over 30 seconds until I was able to roll the sled over and get the throttle paddle out of the snow. The problem began immediately after that event. Sure seems like I have done something to the impeller or the shaft. If any fluid was moving through any cooling circuit, the coolant in the bottle would eventually be at least warm. The hose from the bottle to the engine for bypass mode remains totally cold as well. This should be the first to get warm / hot...

Thank you again for your time on this!

 

[Teth-Air]

Let us know what you find when you rip into it.