Yesterday I took both my quads to meet an old school buddy and his niece so we could all go on a local atv poker run. We put the girl on my 700(she has ridden it a little before). About 2-3 miles from the start the 700 was losing coolant. She told my buddy,her uncle, and he tried to hustle up to the front of the group to ask the leader to stop. By the time everyone stopped, the 700 had built up so much pressure it blew a hole in the side of the plastic sight tank. The previous weekend I'd won the big bore class in a local pulling contest, but had to make 3 almost back to back pulls, after which the HOT warning came on for the very first time. I let it idle for a bit, then used the kill switch to shut it down, leaving the fan running until the fan cycled off. Afterwards the coolant level, oil & everything else seemed fine. The afternoon after the pulling contest I went to nearby drag races & took second in automatic utility class with everything mechanical seeming to be fine. Where should I start looking for the cause of yesterday's overheating, which happened with the 700 in high range, loafing(about 30 mph) along on a public road ? Thermostat, water pump, other possibilties ? I trust my dealer (so far) but would like to have some idea what caused this before going to the dealer. Anyone else ever have the plastic coolant sight tank rupture, and if so, why?

 

Any coolant in the oil? Does it have a miss, or exhaust smoke? how do the spark plugs look?Do they look steam cleaned?

 

is your raidiator dirty

 

I am with him. Is the radiator clean? Can you see day light through it? Was the fan on when it blew or did it fail? Did the temp light come on? Those would be my first guess. Not to knock your buddy or his daughter, but why didn't they shut it down?

 

The oil looks fine. It's only been ridden about 17-18 miles since the dealer performed an annual service. When I loaded it on my trailer yesterday evening to come home and unloaded it today it seemed to run just like always, no smoke from exhaust and it's never yet had any sort of miss. Since I now have a(relatively low-power) electric pressure washer, I wash it often paying special attention to spray the radiator from both sides until the water running off the underside is clear. I've watched closely for radiator or fan clogging since once last summer I got enough mud in the bottom of the fan shroud that when the mud dried the fan couldn't turn. Other than that one incident last summer, the fan has always worked fine & was still running when we put it on a trailer after the breakdown. The girl(only 16) SHOULD have had sense enough to pull over & stop. Maybe her uncle should've stopped her soon as he knew there was a problem, but instead rushed to the leader to let him know we had trouble so we wouldn't get left behind. It was HIS first poker run and I talked him in to going and bringing Crystal to ride with us. No use blaming a LONGtime friend or the girl that wouldn't have been there if not for me. Three miles or less in high gear on a county road wasn't overworking the quad, something failed. I'm just hoping for a clue what failed & why before either I or the dealer's tech have to tear into it. Has ANYONE with a 4-stoke Polaris had a similar incident ?

 

Sorry it came across like that. The point I was trying to get at was, was the fan coming on and did it have a hi temp light? Might indicate a bad thermostat or temp sensor.

 

Wow craneman
never heard of popping a hole in the coolant tank. Hope you figuire that one out