5 replies to this topic

[Beau11]

Hi,

 

I am at a lose here..

 

I rebuilt my 2010 MXZ TNT 600 Carb last year. Over the course of this winter, I noticed I was slowly loosing coolant from the reservoir and figured there must be a leak around the head gasket as many would suggest its a common place.. I do a pressure test and it does NOT hold 15 psi. So I start pulling it apart and noticed a number of things - the power valves had a small amount of milky oil on both sides, removing the air box found some bright green un-burnt coolant inside, and the carburetor has a green hue colour on the air valves. Digging a bit deeper.. pulling the jugs off and found some brown sort of fluid sitting in the bottom of the crank.

 

Ok, so I figured it must be leaking at the head gasket, that would explain milky oil on the power valves and some brown fluid sitting in the crank. Using an oil extractor I sucked out the oil and rebuilt the top end with new gaskets using some Dow111 around the head gaskets (Both cylinder gaskets and the outside head gasket). Now I have the sled rebuilt. I take the sled out last weekend and again I am leaking coolant faster than I was before I rebuilt the thing..

 

Was I looking in the wrong spot? Could I be leaking coolant through the carb into the air box and leaking down into the crank?? I asked the local Skidoo dealer lead mechanic and he couldn't wrap his head around coolant in the airbox. "Coolant in the airbox!???" he says. 

 

Any suggestions??

[stealth bomber]

Coolant flows through the carbs for the heated carb function.  So there is potential for a coolant leak from the carbs. 

[Beau11]

Coolant flows through the carbs for the heated carb function.  So there is potential for a coolant leak from the carbs. 

Yes, I have always left the carb heater off.

 

Where would coolant be leaking through into the airbox?

[yellowjacket]

Maybe, if the reeds aren't sealing well, some coolant in the case could spit back. My Rev used to get gas in the box cause of the reeds.

[Skidoo69]

Turn the heated carbs off and see if that helps

[stealth bomber]

Turning it off wont help.  That cuts off the flow on the left side of the carbs but the circuit is still under pressure from the hose on the right hand side.  If it were me I bould simply bypass the carb heaters with a piece of hose or block off both ends of the circuit and retest.