Radiator removal on a 05 RMK 900 - Pros/Cons?

gunslinger770 said:

We were riding last week and I managed to find a stump on my 05 RMK 900. Upon my outside inspection of the damage, it cracked the belly pan but everthing else looked okay. We continued riding and had a great day - other than me kicking myself for not putting a skid plate on the machine prior to taking delivery of it from my Polaris Dealer.

When we got home that night I ordered a skid plate right up and it came in the other day. I went to put it on and when I opened up the cover to the radiator I noticed that the radiator was munched into a U shape! After kicking myself again and muttering some new unfounded words under my breath I called my local Polaris dealer and ordered a new radiator to the tune of $302, not to mention the other items such as a new belly pan and the cost to have it put in as the sled is still under a 3 year warranty. (They tend to get fussy if you mess with doing things yourself while the warranty is still intact.)

Anyway, after all this, I am reading the Snowest threads and discover that alot of RMK riders are doing away with the radiators in the sleds and bypassing them? Sounds scarry to me but people say they are having good luck with them. I run rail scratchers on the 159 on the trail and do alot of mountain powder riding too.

Anyone had a bad experience with the radiator removal kits and will it void my warranty if I were to do this? - I would think that it would!

Pro's / Con's? & I would prefer only comments from riders with experience in actually doing this rather than opinions....I have enough of my own in this department. LOL!

Click to expand...

The front radiator adds heat at low speeds or the front screen gets covered with snow/ice and the front radiator no longer has a cool air flow.

Removing the front radiator reduces heat and reduces weight.

Pros - weight savings, no chance of what just happened to your rad and my sled runs cooler. Also it's another reason to check out stuff like your oil cable and throttle body boots while you have the exhaust and the intake off.

Cons - none

I don't know if you've been watching this forum very much over the last few months, but here's a few good threads on the radiator issues:

06 RMK Radiator removal
Hot, Hot, Hot
05 900 high temp boondocking

I took mine out the first year i had my 900!! Temps run just fine. i have ice scratchers for the not so good snow conditions. Still got my radiator it makes a nice paper wieght!!

See the comments by Mountainhorse on this thread.

http://www.snowest.com/forum/showthread.php?t=55015

In addition the flow rates are of wrong proportion to to the front / rear radiator. Removing the front radiator allows more flow to the rear where it is more effective at removing heat.

extra weight

You don't need the front radiator. My dealer takes them out. Sleds run cooler without them. The reason is that most of the cooling would go through this small radiator without getting cooled off and no coolant would go through the running boards. When you take it out put an inline connector where the Tee is and block the line comming from the bottle. Now all the coolant has to go through the rear cooler. My sled runs cool this way and I hardly ever need my scratchers.

markoo said:

You don't need the front radiator. My dealer takes them out. Sleds run cooler without them. The reason is that most of the cooling would go through this small radiator without getting cooled off and no coolant would go through the running boards. When you take it out put an inline connector where the Tee is and block the line comming from the bottle. Now all the coolant has to go through the rear cooler. My sled runs cool this way and I hardly ever need my scratchers.

Click to expand...

If polaris has not put in a front cooler from factory in 07 and 08 then there is no need for it.
I have 1000 miles on a rad delete and works flawlessly. The reason is because what Markoo said ^^^

We own 2ea 05 900 159 IQ's

Both sleds have the front radiator removed.
My wifes 900 runs at 122-135 water temp on groomed trails with ice scratchers.
My sled runs 96-114 degrees on groomed trails with ice scratchers
My sled has alot of work done to it including a dyno tune and custom head.

remove that sucker, it is NOT needed.

Gunslinger,

The warranty issue is completly up to your dealer that will do your service. They are the ones that will make a stink or not if the rad is removed. If the service manager there says that they will not honor your warranty. If you are nervous about it, keep the stock parts and put them back in if you have an engine problem.

The "cons" would be on icy trails without scratchers or dry trails all together (which would ruin the hyfax before the engine had problems).

Have a look at the diagram and decide for yourself... notice that the coolant does not flow thru the radiatior and then the rear cooler assembly. It flows thru both and will take the path of least resistance.

Two reasons to remove the radiator on 900's (and 755's)

1) The sled will run cooler without it if you have scratchers.
Scratchers are mandatory on these sleds, IMO

2) The radiator weakens the front end plastic.


#1...
If you remove the radiator, do not just put a union between the hoses... that will actually cause the temps to rise... Remove the "T" (can be a beotch if you have big hands) and put the union in there. This removes the dead-loop which robs the rear cooler, running board coolers and front heat exchanger of much needed flow.... plus that hose and the fluid in it weigh probably 3+ lbs.


#2

If you think about it, the "radiator" depends on airflow THROUGH it that means that the nose-grille and the area behind the the radiator must be free of snow... When you use the SNOWmobile in the SNOW... the grille and the area behind the rad pack with snow...That turns the "radiator" into a "heater" inside the nose of the sled...adding heat to the under hood area . Remeber this is a free-air design, no fan or ducting force air thru this snowpacked grille. At that point the radiator is more like a heater in the "box" formed by the nose pan and "shelf" above it.

PLUS

This "heated box" in the nose makes the plastic soft (really soft) so that when you yank on the already weak design of the RMK nose assy by the bumper, things tear off!

The radiator design was, IMO, one of the bigger blunders on Polaris' part, taking into account the plastic construction and lack of airflow in real world use, ... that they remedied in 2007 and 2008.

Think of the 2008 800 Dragon 163" RMK.... This is probably the lightest, Highest HP stock sled that Polaris has made with one of the highest loads (163" track)... That power and load make a lot of heat... not only does the dragon 163 run in an acceptable temp range in most conditions, it does so without a radiator or running board edge cooler (which your 600 and 700/900's have) AND on the 163's it does it, STOCK, without a front tunnel/bulkhead cooler.

Power to the people.



See any snow on this TRAIL machine grille (much less a mountain machine).


How 'bout behind the radiator??

Too Cool?????

410Fortune said:

My sled runs 96-104 degrees on groomed trails with ice scratchers
My sled has alot of work done to it including a dyno tune and custom head.

Click to expand...

Did you remove the t-stat on your sled?? (RK Tek)

Is the motor running that cool robbing hp?
What kinds of temps did you keep while tuning it on the dyno (that should be in your dyno runn print out)?

Cooler is not always better, there is an optimal temp for efficient combustion etc.

Mountainhorse,

I agree 100%

I have not checked to see if the thermostat has been removed, all the work was done by previous owner

My sled is overcooling

Every week I have one of our 3 sleds in the garage for work/maintenece.
But thats expected when you buy 3 used sleds, we have not missed a weekend yet! (long Friday nights!!)
They are all almost 100% now, escept yesterday my sled has now developed a coolant leak, I suspect a hose under the resevoir, diggin into that this week.

the dyno tune was done by Xtreme Performancein Danco CO, back in 05 this 900 was their test mule for their RMK power package.
Sled has 1200 HARD miles on it, but it runs tits for me, I have been doing alot of work un-doing the hard miles...oiler cable, dirty intake/reeds, loose steering, filters, fluids, etc etc
The cooling system is next. I will also likely replace the radiator cap and the thermostat while I am at it, if it does have the OEM thermostat I will test it before I buy new. I have a coolant system pressure tester to help me find my leak...I am hoping my adapter fits the small resevoir cap opening.

When I hit the trail I let it get up to 130 degrees or so, then I put my scratchers down. It sits right at 100 or so degrees water temp the rest of the day, between 10,500 and 13,000ft. The ambient tempature does not seem to effect it much it can be 5 out or 40, as long as some sort of snow (ice cubes) are hitting the rear cooler, it runs right around 100 degrees.

I know overcooling is BAD especially with later model computers...I will fix it

My point for this thread though was to share that both of our 05's have no problem stayting cool, even on hard packed trails, without the front radiator.
We put about 120 miles on our sleds this weekend what a BLAST they are

I also edidted my above post to be a bit more accurate, they will see slightly higher temps when climbing hills, lumbering along, etc

BTW what is TOO HOT for these engines? I am quite new to snomobiles and my jet skis have never had a temp gage...what should they run at? What temp is it time to shut her down at in case they ever do heat up?

I REALLY APPRICIATE feedback like this...thanks for taking the time to point that out and post the radiator info for the benefit of this thread...you rock!

Also I wonder if anyone has attempted to run the front mount radiator in series with the rear mount rails and cooler, instead of parrallel?

That would eliminate the possability of the coolant "choosing" a path...

Not necessary just thinking out loud.

I personally like all the space you get up front without it, not to mention the 10# savings

I wonder what people are using these rads for. I see them on ebay with bids on them. Just curious cause I have a nice paperweight rad if someone needs it. I don't have that much paper

IMHO, running with or without the front radiator sucks.... I bought my 900 used, without a front radiator, so I don't have any experience with one in.

Here's what I think....
1. I could see how running the radiator and rear cooler in series could be a decent combo, but this is the first time I've heard that it was ran in parrallel from the factory. Now I can see why it wouldn't help having that front radiator. (Polaris, I love your RMK's thoughout the years, but running a rad/rear cooler in parallel is just flat stupid. Were you guys out drinking the night before and came to work and designed the cooling system with a hang over???)

2. Running with a rear cooler only isn't all hunkey-dorrey either.... It's a PITA some times running scratchers all the time. Scratchers fling snow EVERYWHERE, including bouncing off the back of your shoulder/helmet, and any other riders close by. Infact, I miss the cooling system on my '03 Escape. No temp guage that I feel I need to watch, and a cooling system that almost always is up to par in anything but super icy trails.

3. What polaris should have done was go the traditional route and run both a front and rear snow cooler. It's worked for years, why stop and come up with some FUBAR'd system????

I might look into how hard it would be to change the rear cooler and go with one of those massive VanAmburg coolers, or something that is bigger than stock where I can actually run down the trail more than a mile before I have to drop a scratcher down.

RJF said:

2. Running with a rear cooler only isn't all hunkey-dorrey either.... It's a PITA some times running scratchers all the time. Scratchers fling snow EVERYWHERE, including bouncing off the back of your shoulder/helmet, and any other riders close by. Infact, I miss the cooling system on my '03 Escape. No temp guage that I feel I need to watch, and a cooling system that almost always is up to par in anything but super icy trails.

Click to expand...

Call me insane, but I actually like how much snow gets slung by my scratchers. Keeps some of the other people that are trying to crowd me on the few trails I ride off my back. Its also pretty funny when my riding partner and I are doing the drag race back to the truck and he's right on my tail getting the "Nose Bleed Cloud." We call it that because it makes you feel like your nose should be bleeding from the ice cloud.

Call me crazy x2 because I just removed the front cooler from my 05 edge and went with a VanAmburg double pass rear cooler only.

I bought the 900 from an engineer at Polaris and he removed the front radiator.

In a perfect world with a perfectly working system a parrallel cooling system will work BUT THE CONDITIONS ARE NOT PERFECT.

Things get clogged up with snow and ice, the air flow may not be adequate.

The big moment is when you are in powder going 3 MPH with snow coming over top the hood and the airflow to the front radiator is dramatically reduced.

Once you get out the powder the front screens are clogged and now the front radiator is being heated by the engine and exhaust.

ttt