Blowing cooling hose?????

[SpencerA]

Blew cooling hose off XLT yesterday. Ran for about 12 miles before it happened. Upper 160's for water temp. Sled was able to cool down everytime I went in powder till about the last mile and it really didn't cool down much.

I had a air bubble in line 2 rides ago but I wasn't able to make it but maybe half mile before it overheated. Jacked the front way up and got that fixed.

The sled didn't overheat it just popped hose off that I know was clamped tight. So I'm getting too much pressure in my system.

Head gasket, O rings for SLP heads, Water pump, are all my suspects of the problem, what do you guys think. I heard there was a dye you could put in your coolant to see if your getting a leak???? I don't think its air because that was pretty far to go before it built up enough pressure to blow.

 

[BB454]

Loose water pump belt.

 

[SpencerA]

Update

So I just ran the sled at idle for about 15 minutes. All the hoses and coolers were warm to hot so I know I'm getting flow. Got temp up to 160 but not concerned because sled wasn't getting cooled from snow. Being that I'm not overheating and its a pressure issue that makes me believe its the SLP heads or wrong size cap. I have a 20psi cap which I'm thinking might be too high. That may be the reason I was able to make it 12 miles before the hose blew. The water pump wouldn't cause excessive pressure?? So if I had a slight defect in one of the heads I'm thinking it could possibly build up over time enough pressure in the system. I doubt its the O rings as their brand new but I guess you never know. Any other input would be appreciated.

 

[ttyR2]

You should be able to pull the cap once it cools a bit, then start it up and see if you get any bubbles coming out. If so, you have a head gasket leak.

 

[cowboy181d]

checking for a bad head gasket/head defect is pretty easy to check out if you have access to a block checker, most mechanics have them. they work great, just fill the tester, warm the engine up(warm but not hot enough to pressurize system) stick tester on filler neck and watch for bubbles in tester and or for the test fluid to change colors. It sounds like a small leak from combustion chamber to me.

hope this helps!
damen

 

[SpencerA]

No bubbles but that being said it made it 12 miles before popping off so it might be such a small imperfection that i might not see any air bubbles.

 

[SpencerA]

I didn't take cover off to get to water pump but I could see it from the front and was able to push a screw driver on it to see how tight the belt was. I'm guessing I had about 1/8 inch to possibly 1/4 slack. Belt looked good. Obviously I didn't look at impeller but at that slack could the belt slip? Belt looks good condition.

If the cooling system were to slowly increase in preasure would it cause my water temp to go up a little? If I ran a smaller cap would the system been able to blow off before my hose came off?

 

[cowboy181d]

I usually run the belt a touch tighter than that on my 650(book says 1/8 to 3/16 deflection)...yes if you had a smaller psi cap it should have blown off before it blew the hose and a high pressure cap can allow a touch higher temp(not drastic but it can effect it) as it will allow the system to run at a higher pressure.Which in effect raises the boiling point of the coolant in the system.Sounds strange (and is way off snowmobiling,lol) But I run a 32lb cap on my dirt late model stock car in order to make force it to cool better!(works great but man you wanna hear a POP!! what till one of them hoses comes un-corked!!!! )

 

[SpencerA]

Well I'm going to try a smaller cap first before tearing into my motor. I was running upper 160s in temp at about half throttle on trail with scratchers down. Some might say thats fine but the snow was real loose. If it would hit 170 i would get off trail and for the most part it cooled down until the end of the ride before hose popped i couldn't get it to cool. I'm hoping that it was just too much pressure not allowing to cool down.

On another note is it true snow flaps cool your motor?;

 

[rmk4ever]

Head gasket. Plain n simple, usually blows the cap off of tank , then all over right leg. Exhaust gasses get into the coolant & expand. You can let a mono block idle all day & it wont produce 1 bubble, now put a load on it (going down trail) which ever is the weakest link will fail first. In your case it was the hose clamp.

 

[SpencerA]

I'll pull the head and take a look at my o rings this weekend. You would think my sled would over heat if it was that though.

 

[rmk4ever]

So what did you come up with? 93 & 94 motors are the only ones with o-rings, all others are gaskets 95-2000

 

[SpencerA]

So what did you come up with? 93 & 94 motors are the only ones with o-rings, all others are gaskets 95-2000

Ended up not tearing into the motor today. I have a 97 with the SLP Heads so they eliminated the head gasket and now has O rings. No matter what I'm taking the heads to the machine shop to have them shaved and then put new o rings on. I think your right rmk4ever when you were talking about a load on the motor. Did the pressure test and it was ok but not able to get the motor up the heat produced when under a load.

Going to try to find a 13lbs cap, anyone know where to find one for a sled? Also going to put a snow flap on, I never realized that on the trail the flaps really help with cooling. Already have scratchers but anything to help.

 

[SpencerA]

Pulled heads off today. They looked prestine but that dosn't mean much. Took them to the machine shop today. Curious what they find. I guess my mono block could possibly be warped.

Anyone on here have the SLP heads? The restriction plate they sell with the kit seems to have very limited cooling ports for the heads to get cooled. I've never heard of any issues with that but just curious.

 

[SpencerA]

Update.

So after a lot of talking to SLP and the machine shop we think we figured out the issue. This is really helpful if you ever decide to run SLP heads on these triples. Machine shop found the cylinder heads had .002 runout which they felt wouldn't cause a issue. They felt it was the o rings. The rings only seal off the coolant at initial warm up from then on its head to cylinder contact that seals so these have to be absolutely perfect fit. That is why they think at higher RPM I was getting more gas leakage. So decking the cylinders today and throwing it all back together. We'll see what happens but I'm pretty confident we solved the problem.