2013 Pro RMK 800 Coolant leak high rpm

[RickCA]

Got a weird issue.

2013 Pro RMK 800. Rebuilt about 800 miles ago. Got an intermittent coolant leak. Sled runs great, pulls hard, never overheats. but when i give it WOT for extended periods of time, racing. and or clutch testing, high rpm pulls. I notice my coolant bottle low and coolant spray around the engine bay.

Having a hard time pin pointing where it's leaking from as it doesn't seem obvious. I'm guessing with how it's responding/acting maybe a head gasket oring starting to fail. Any other suggestions on where to look. I'm gonna pull the engine this summer and go through it.

 

[PSI 800]

Not sure who makes it but there is a colored dye that you can buy to put in anti freeze for finding leaks. Get a coolant pressure tester and the dye and see if that helps in finding your leak

 

[RickCA]

Good call, i'll ask around my friends see if i can get my hands on a coolant pressure test kit. I'm suspecting it's a head gasket o-ring just due to the fact that it only seems like it happens after a long pull. really Hoping it's not a crack anywhere I'm suspecting its pressurizing and overflowing out of the overflow.

 

[blkspd]

Its a head gasket that's building the pressure.

 

[RickCA]

Havn't pulled it apart yet, getting ready to. You guys think it's possible it could be something to do with the oil pump mechanical seal? I did have to replace it on my rebuild. I'm still leaning toward the head gasket O-Ring. Hoping it's obvious when I pull it out and tear it apart.

 

[PSI 800]

I would say head gasket

 

[RickCA]

Just pulled the head and head gasket. Not seeing any signs of issues really. Maybe possibly it's just the tiny o ring around the piston. That o ring looks in tact. But man that thing is tiny. Does anyone recommend putting a dab of any type of gasket seal around that oring? Or do you install dry? Or 2 stroke oil when u install? Thinking this time I will re torque those head bolts after a few heat cycles as well. They were all fairly snug still.

 

[RickCA]

Just pulled the mechanical seal. I'm pretty sure it was the root of my problem. Milky substance behind it. I can see in even wear almost as if the outer portion that rotates was not spinning true. I had issues when I originally installed this seal last rebuild. Installed a new one and going to hope it's fixed! Getting cylinders repaired and re plated and new pistons.

 

[Scott]

Glad you found your problem. I was going to add before I saw your post that if there is any milky gray antifreeze or residue in your antifreeze bottle then you definitely do have a seal that's broken.

 

[RickCA]

Yea it seems likely to me that this mechanical seal was the problem. I had no milky residue anywhere in the cooling system other than some right behind the seal that is directly behind the mechanical seal. Even looking down into the crankcase i can see the small pooling of oil that looks perfectly clean. any water that was getting in was such a small amount that i'm likely lucky I caught it when I did. hoping when I re assemble I can get many trouble free miles out of the engine!