'17 M8000 so hot blew radiator cap - Happened to anyone?

[brdemorin]

A nephew of mine jumped on my '17 Arctic Cat M8000 and ended up driving it until the radiator cap blew and shot antifreeze all over him. He wasn't paying attention to temps. It hasn't started since. Happened to anyone? What did you have to fix?

It got so hot, the reservoir is now oval instead of a circle. I pulled plugs to clean them and blow out the cylinders. When I pulled the pull start with the plugs out, so much fuel shoots out the cylinders that there's no way that's normal. I'm thinking injectors might have melted. Assume might need pistons/cylinders as well?

 

[boondocker97]

If it really got that hot I'd be considering a new crate motor for $2400 from country cat. Was it all fuel coming out or some antifreeze too?

 

[brdemorin]

All fuel. No antifreeze on the plugs when I pulled them

 

[kidwoo]

These things absolutely drench themselves in fuel when they overheat as a way to cool down. I overheated coming back to the trailhead one day and the next morning it was so flooded I couldn't start it until I got it home in a warm garage and let some evaporate off.

You should definitely check all plastic bits and wires but I wouldn't just assume you melted the injectors. (I have a pair of squares if you need them btw). I always thought they shut down at a certain temp but I also don't let mine overheat anywhere near that much.

He likely just flooded the crap out of it. They will accumulate a scary amount of fuel in the case when this happens.

 

[sno*jet]

yeah i thought they just start dumping in so much fuel to the point the motor wont run. id top the coolant and see if she fires. if youre concerned pull the pipe and look at the piston faces. a 17 might be ready for a top end anyway if you have a lot of miles? over 3k?

 

[brdemorin]

Took it to dealership who pulled it apart and said needs a top end and bottom end for $6500. Ouch. I'm going to buy a crate engine from country cat ($2400) and install myself. These cats use the same identical engine from '10-'17?

 

[boondocker97]

Yep, same motor with tweaks to the exhaust and mapping.

 

[Diesel0889]

My 17 m8000 gets the temp light on hard pack snow going slow if it's kinda frozen, even with scratcher down. My 10 NEVER once! Thinking about adding a cooler to avoid it all together. I'm sure others have done it. A 16 limited I looked at had one dealer installed (wish I had looked at the set up). Maybe a good idea for yours as well if you are on trail to the good stuff etc. I'm still researching it. In soft spring NH snow I never saw over 130 (on the factory guage around the yard, also no blinking light.

I do agree looking at the pipe etc but sounds like it's all apart. CC crate motor is def the way to go. Id also have them show you as well. Not all dealers are created equal and will want to do unnecessary work. Sorry to hear that yours is in such bad shape! The weight wars on mountain sleds has made them more fragile. Cat has to know we need to ride trails to the powder!

I do know one company makes a cooler add on for the accender chassis not sure on ours yet as I have not called them. I hope you get it sorted. 6500 sounds nuts to me. A crate motor and a 12pk if it were me. Let us know what direction you go! I wish you luck!

 

[summ8rmk]

Add a length of rubber to ur snowflap, let it drag the ground while on the trail and temps will drop a lot.. keep ur speed at 20mph+





Sent it

 

[brdemorin]

Engine on its way. I've never done the rip and replace so will let you know how it goes. Ya, I was super skeptical as to whether the crank really need to be done because they seemed to side step when I asked if they pulled the engine to find out. Plan to rebuild the whole motor anyhow so we have an extra. We've got 5 cats so will come in handy at some point

On temps, I've read some good things about guys using SKI-Z so plan to try some of those

 

[brdemorin]

UPDATE:

Shady dealership never even took a single thing off the sled to look at it. Took it home to work on myself.

Turns out it didn’t need a new motor at all. @kidwoo was right. It was just flooded badly and that’s why it wasn’t starting. Compression look good but still wanted a good look at the pistons. Glad I did. Top rings on both pistons were welded into the piston. Some minor scarring on the cylinders but honing cleaned them right up. Could see all the fuel floating around in the crank.

Besides the top end, had to replace coolant tank since it was hot enough to warp the opening from a circle to an oval. Also needed a knock sensor since it was slightly melted on top.

For top end, went with SPI pistons, bearings from OEM, and winderosa top end gasket kit kept the whole top end job to $250