900 Coolant Overflow - RAD Delete Kit

[Dirk Diggler]

Hi - I've recently rebuilt my 900 (like many others) and installed the RAD delete kit from SLP. When I run the sled, it runs strong and stays anywhere between 125-145 degrees...which is fine, however, when I run the machine hard or extended period of time (over 15 miles) , coolant is getting pushed out the overflow tube in the reservoir bottle.
The faster the pump/motor turns over, the higher the level gets in the coolant bottle and starts to overflow???? It doesn't seem to be air locked because the engine is cooling and the rad's get hot...so i know its circulating.

Has anyone else had this issue??? Any Suggestions? I've already eliminated the extra loop that was left when removing the rad....my engine would not cool properly with that left in the loop (PS - thanks for putting the loop elimination diagram on here!!!)

 

[sno_mo_racer]

Question, are you in the flatlands running trails or in the mountains. If a flatlander or ride a lot of trails mixed with mountain riding, then put it back on as you will always be overheating without it unless you have good ice scratchers. The rad delete is mainly for mountain riders who see little trail use.

 

[Dirk Diggler]

I'm mostly running in the flatlands...I live up north! mostly -40 degrees C and below...brrrrrrr!
But I'm not having issues with overtemperature as such... I still managed to run the machine for 20-30 minutes at 125-145 degrees C. When it starts climbing, I just pull off into the powder and the temp goes right back down.
The only issue im having the the coolant overflowing from the reservior bottle...it's like its expanding too much and comming out. After extended periods of riding, its pretty low in the bottle....amd I'm covered in coolant!
Is it possible I have too much coolant in there? Since I removed the "dead" loop and the rad the sled should require less coolant correct?
Is there any know issue with plugging the overflow?? It would at least stop the collant from flowing out...but not solve why it is!
Thanks for the response.

 

[Rowboat]

When I deleted my rad, I ran into the same issue... rode for a good hour without seeing high temps, looked behind me and saw a pretty coolant trail following... mine was air locked... parked her on an incline on the mountain, didn't have any tools to get the bleed screw so I just kept throttling on and off and after about 15 min it pushed the air through itself... topped the tank off and have never had an issue since.

I'd bleed your system just to be sure... costs nothing but a small amount of time.

 

[94fordguy]

You should also try a new cap on the coolant bottle, they can wear out over time and then are unable restrain all the pressure the system often creates. I'll fill my sled up and ride it and let it burp out what it doesn't want and it seems to be happiest at about 1-2 inches BELOW the cold fill line when the sled is cool. If I try to fill it right to the line, it will ALWAYS burp some out and make a mess. As long as it doesn't overheat or run extremely low on coolant, you will be ok.

 

[quarters]

This is good info.

I just did a rad delete over the summer and have yet to put any real (just urban) miles on it. Have a trip to Fernie planned in a few weeks. if something comes up, i'll know what to do.

 

[High Velocity]

I'm thinking along the same lines as Rowboat. Did you raise the front end to bleed the cooling system ? I always raise the front end at least 3' to ensure any air trapped in the coolers is bled out of the system. If you did this, then I would suspect that you may have possibly damaged/nicked a head o-ring when assembling the engine.


Sent from my iPad when I should be sledding.

 

[sno_mo_racer]

I'm mostly running in the flatlands...I live up north! mostly -40 degrees C and below...brrrrrrr!
But I'm not having issues with overtemperature as such... I still managed to run the machine for 20-30 minutes at 125-145 degrees C. When it starts climbing, I just pull off into the powder and the temp goes right back down.
The only issue im having the the coolant overflowing from the reservior bottle...it's like its expanding too much and comming out. After extended periods of riding, its pretty low in the bottle....amd I'm covered in coolant!
Is it possible I have too much coolant in there? Since I removed the "dead" loop and the rad the sled should require less coolant correct?
Is there any know issue with plugging the overflow?? It would at least stop the collant from flowing out...but not solve why it is!
Thanks for the response.

Cool I am from the north also. Nunavut here, hope you get it figured out. If the heat exchangers are heating up do not think also it would be air locked. With the front rad out for non mountain riding there really isn't enough cooling for on the trails. The mountain rids can get away without the front one because they are always in powder so the other coolers are doing the work. Think that is pne reason polaris designed the 900 system the way it was. If you are in pow then it "supposed" to use the rear coolers, but if you are riding on trails it "suppose" to use the front with airflow cooling it. But there is a design flaw somewhere so it just creates a dead loop and doesn't work the way it was supposed to. I have a 121 and no mountains in the north so I left the front rad on and removed the dead loop and made it work in one full cycle as the thread on here somewhere.

Since you mostly ride trails am guessing there will be no fix to your problem unless you put the front rad back on and remove the dead loop. Not all remidies on snowest works for us flatlanders as I have found out. Good luck in solving your problem.

 

[Dirk Diggler]

Hey guys - thanks for the responses and sugegstions.
Couple things:

1) I parked the sled on a BIG bank and bleed it with the bleed screw until water / coolant came out...My rads are getting hot, and as soon as I pull off into power or put snow on the rear rad, my temp immediately goes down. So I really dont think airlocked is the issue. However, as stated its a cheap "try" so im gonna put her back up on an incline again tonight and bleed and bleed!

2) It's the "boiling" or forcing of the coolant out of the bottle that really gets me. Its NOT overheating...even though I am flatlands rider, there is a ton of powerder in town, so I pull off the trail frequently and manage to cool her down all the time(125-145)....I dont think I have many of the old pieces to switch back to the rad install in the front (ooopps). Not an option.

Has anyone ever blocked off the overflow from the reservoir? I was thinking of obtaining a somewheat "happy" level and blocking off the overflow???? Is there a problem with this pressure wise? Anyone know?
It seems like the overflowing is my only issues...however, I dont want to cause other problems by doing this....thoughts?

 

[monster715]

Flatlander here as well from Wisconsin. I had all of these same issues as well with removing the front radiator. The last two winters I ran with scratchers and that worked great to keep the sled cool. However, with the lack of snow we had, it seemed like we were riding on a lot of dirt or 'snirt' and those scratchers acted more as a sandblaster to my rear skid. Really made a mess. So this past summer I installed a 4' long u-cooler. It does work better but it really depends on the trail conditions. It all comes down to whether or not you are getting snow up on those exchangers or not. If not - it doesn't matter how big of a u-cooler you install....its gonna run hot. Luckily I mostly ride off-trail up in the UP of Michigan and this is not a problem.

Right now - if we do ride on trails and they are pretty hard packed.....I will actually move to the back of the group. That way everyone somewhat loosens the snow up and I have found that to help.

One last thing.....what type of snowflap do you have? Believe it or not but a bigger snowflap will help to keep snow dust circulating up around that rear heat exchanger which in turn will help the sled to run a little cooler.

Good Luck.

 

[05900]

Ck your thermostat ? Radiator cap is same as Subaru ...really.. go steal one off neighbors car or get yours checked. Restrictor in coolant hose? was part of the kit.
READ sticky about rad delete at top of forum and make sure lines are routed correctly.
good luck!

 

[tweeds]

I also had an overheat issue with my 05 900 166". Always overheating and slp rad delete kit was installed b 4 I got the unit. After talking to fellas at slp ( thanks again guys) I checked the hose routing and all was good however the restrictor was missing. Put that in and no more issues. My 2 bits.

 

[sloan188]

I had a similar issue where I was losing coolant (no rad delete kit). It turned out to be the rad cap. The spring was fine but the rubber gasket on the underside (bottom of the spring not the one on the bottom of the cap) was off-center and not sealing and allowing coolant to blow by. I've got a new one on order and in the mean time, I make sure the rubber gasket is properly centered whenever I put the cap on.