I can't .....

[Ron H]

...find any meaningful info on Polaris rzr1000 thermostats...Im looking for...
1) What temp do they open...
2) What temp do they close...
3) Are there (and I think there must be) non oem thermostats that operate at lower
Polaris OEM specs.
4) I'v found there is some mention of having to "reflash" the computer however
given the engine runs fine as it warms up to normal (personally I think they run
to hot) operating temps I don't see how the engine running +- 15-20 deg cooler
would have much if any effect...
5) Am I missing something or is there anything I should consider? ...I've always
believed heat robs power as well as shortens engine life....

Here is the response from Polaris, reading "between the lines" I think their hands are bound by regulations.....

Hi Ron,

Thank you for contacting Polaris Industries in regard to your RZR. I understand that you are looking for more information on a new thermostat potentially. However, Polaris is only able to recommend OEM thermostats. Using aftermarket thermostats may affect emissions. Polaris is federally mandated and restricted due to emission regulations. Additionally, engine thermodynamics and efficiency is maximized at the recommended, calibrated thermostat temps. The only information Customer Service can share is information that is otherwise shared publically on our website or in your Owner’s Manual.

Please let me know if you have any other questions or if there is anything else I can do to assist. I can be reached at 1-800-765-2747 or by replying directly to this email. You may receive a brief survey at this email address inquiring about my service levels with regard to your concerns. If you wouldn’t mind completing it, I would very much appreciate your feedback.
Thank you for riding Polaris!

Respectfully,

 

[teeroy]

found this on a rzr forums thread, hope it helps

https://www.rzrforums.net/rzr-xp-turbo/276649-thermostat-options.html

edit: ah, just noticed it's for a turbo...sorry

 

[the_real_wild1]

If your engine is overheating you need to look at the aftermarket stuff you added. The pipe is one. Needs to be programmed for mods to make sure your getting the right amount of fuel. Not sure if you have changed anything in the intake or not? Also you should either add a second fan or build a should around the current one that rad needs air flow going through it. My cat rad had two plus a big shroud. Hopefully this helps some.

 

[Tchetek]

Are you asking for about the thermostat in the coolant line that bypasses the rad until temperature is up. I believe this likely is open all the time except for in the winter.


Or the sensor that engages the fan to start cooling the coolant?

I only have an 800 but I also believe the fan engagement point could be a bit lower. On the 800 the fan does not turn on until 196-200 degrees f. That is pretty close to boiling before the fan even starts cooling! It has gotten pretty warm on some long mountain climbs or wfo down the road on really hot days. My rad was also a bit low on coolant the first time and I didn’t know how the gauges displayed temperature yet.



I looked a a few options to keep it cooler.

-I wired in a manual switch so I can turn on the fan early before a big climb or road drag. Also doubles as a back up if your fan circuit has issues on the trail and you can manually run your fan to get home.

- can add a resistor in the temperature feedback circuit to make the ecu think it’s hotter than it is by a few degrees. Then fan on/off set points would be a bit lower.


- increase rad volume with aftermarket rad to cool more volume when it does start cooling.

-Evans coolant won’t boil over.


-make sure your system has no leaks. Pressure also increases the boiling point of your coolant.


All of that said I now keep the gauge showing engine temp and keep an eye on it. Now I drive a little more accordingly if it starts not to cool fast enough and ease up a bit. Sometimes not a option though so the switch can be flicked.

 

[Ron H]

There are no overheating problems , I did a relocate with a double bypass racing rad. This rad from Howe racing and is typically used with 7-800hp race cars..
My train of thought is two fold , heat robs power, and secondly running the engine cooler will add to engine life....
Of course keeping the rad out of the mud is a short coming with the vast majority of OHV’s.
I don’t nessarily need/want to run a lot cooler but keep my max running temp around 175-180deg as opposed to 195-200deg.

 

[the_real_wild1]

I think the only way is to change the thermostat. Need to check the rzr forums to see if someone has done it and found the part at somewhere like Napa. Can also get a programmer to lower the start temp of the fan. But being in the back it will be loud. Need to crank the tunes more so you can’t hear the fan.

 

[Ron H]

I think the only way is to change the thermostat. Need to check the rzr forums to see if someone has done it and found the part at somewhere like Napa. Can also get a programmer to lower the start temp of the fan. But being in the back it will be loud. Need to crank the tunes more so you can’t hear the fan.

Actually the fan does come on for about 30 seconds, when the thermostat opens up you can see the temp drop by 1deg every 2-3seconds. This pretty much given the additional cooling capacity of the Howe Rad (50% more coolant) I'd suspect with a lower operating thermostat the fan may not even bother coming on as it is set to a higher temp.
As I understand the fan is controlled by the computer which in turn "basis its descision" so to speak on what the temp sensor tells it...
Finding a lower temp replacement thermostat is exactly what I'm after. I've also had a suggestion of drilling a "bypass hole" in the thermostat

 

[the_real_wild1]

You can take it out and try it. But then make sure it goes back in for winter.

 

[Ron H]

You can take it out and try it. But then make sure it goes back in for winter.

Running without a thermostat certainly is an option however I just checked my birth certificate and my memory isn't what it used to be...
Not really a big job but I'd rather just drain, burp, gasket once over twice. You figure Napa has the best selection in thermostats?

 

[Tchetek]

Don’t think that will do anything for you. Fan will still engage at the same points.

Initial warm up will just take longer.

Look at your manual. The temperature feedback is fed back to your ecu as a resistance.


Adding a resistor in series or parallel can fool the ecu. But you will need to do some math to figure out what resister and series or paralleled.

 

[Ron H]

Don’t think that will do anything for you. Fan will still engage at the same points.

Initial warm up will just take longer.

Look at your manual. The temperature feedback is fed back to your ecu as a resistance.


Adding a resistor in series or parallel can fool the ecu. But you will need to do some math to figure out what resister and series or paralleled.

I do get that, and a good mod to perhaps get a little extra cooling out of the stock rad or even aftermarket... However Id think if the Thermostat is full open at 180deg as opposed to 195deg the fan may in that case never/or rarely come on as the Howe rads capability/capacity far exceeds OEM (Extra 2-1/2L coolant over stock, keep in mind much shorter lines as well).

 

[Ron H]

A little update, after scouring the universe I've found a thermostat which will open at 170f...
Not exactly the right size the bypass portion is 3mm longer, the diameter of the mounting ring is 3.55 mm bigger..
The mounting ring is no biggie but the bypass portion might be an issue... I'll have to research that a bit....

 

[DaveB]

Send Steve at Monster a note. You PoPo is probably like the Canned Hams in the temps dept. The thermostat controls the opening to aid in warm-up, but the computer controls the engine temps with the fan on and off settings....and they are made to run HOT for emissions. On the BRP units he can set them where ever you want them.

 

[Ron H]

Send Steve at Monster a note. You PoPo is probably like the Canned Hams in the temps dept. The thermostat controls the opening to aid in warm-up, but the computer controls the engine temps with the fan on and off settings....and they are made to run HOT for emissions. On the BRP units he can set them where ever you want them.

I'll contact em tomorrow, and yes in conversation with Polaris amongst others the primary reason for running "close to the edge" is emissions. If I get their "full on" tuning I suspect this will make my Dobeck redundant. If that's the case I can put the belt temp gauge in its place."