My MXZ440 is leaking injection oil, and I am not sure where it is coming from. The sled starts and runs fine, but after it runs for a few mintes it leaks oil. It doesn't leak right away so you can see it, but if it is left overnight there is a mysterious puddle of oil (photo below)? I have loked all over to find out where it is coming from but it leaks so slow that I can't pin point it. I thought t was the base gasket? If anyone can help me it is appreciated.

It can come from several places. First look at your coolant and see if it has a black look to it. The Rv shaft seal will leak oil into the cooling system. There is a small weep hole in the area you are pointing to so it may be coming from the pump/ rv seals, pretty common. I've found a couple of case bolts with no threads on them, they were made that way, one didn't leak for 2 years. The base gasket doesn't seal the RV gear chamber.
If you really want to find it before you tear it down go to an auto parts store and they have a die that cane be put in the oil. Then you use a black light to find the source. Usually if you wipe everything of real well then look for the drips you can find it.

Is it leaking out of the exhaust?

I do not believe that it is leaking out of the exhaust, however, today I am going to take the Header and the Carbs/Airbox off so I can get a better look at things. My coolant doesn't look like to have any oil in it, but I thought it may have been leaking where the Coolant line comes out in the front of the motor. Is that possible?

If its a rotary valve, and coolant was leaking into the rv shaft oil, your oil will turn white, first in the line from the oil reservoir to the rotary shaft.

Do you mean the oil return line on the back of the motor above the carbs? This line looks like it has tiny white bubbles in it, but the oil in the resevior is clean? If it is the RV Shaft Oil seal where would the oil that is pooling up leak from leak from? Will this be something I can change myself?

IT COULD BE THE ELBOW YOUR OIL LINE CONNECTS TO BEFORE GOING IN BY THE ROTARTY VALVE. (IT IS ROTARY VALVED, RIGHT) THAT ELBOW MIGHT JUST NEED TO BE THREADED OUT AND TEFLON TAPED.

It is rotary valved, I will check that elbow when I get out of work today.

I forgot to mention, the oil that is leaking out is "clean" injection oil.

If your sled has an oil tank check the gromet around the line coming out of it. I know thats probably not the case but I had this happen on a 99 zx mxz so I just thought you could check.

Is it possible it's leaking out of the R.A.V.E valves. My 440 and my 583 both have done that. There is a small o-ring on the shaft inside the valve body. It wouldn't hurt to look there after all the valves should be cleaned once a season anyways. :thumbsup:

Ok so here's an update on the progress. I took off the airbox and carbs this morning and checked out everything. I was suspicious about the gasket on the oil pump but everything was dry including the nipple that is threaded into the motor.

I noticed today that the water pump / coolant line in the front of the motor looks to be wet with oil around the gasket. I ask myself and you guys how can oil be leaking from there and not be mixed w/ my coolant?

is that just some corrosion on your prim. clutch(powdery white stuff) from summer storage or does your clutch always look like that?

Another update:
I removed the header tonight and the bottom of the water pump looks to be wet with oil, seen below in the mirror. Any help or info on the subject would be appreciated.

Well, I think I will take back that last post about the water pump gasket. I believe it is the Crank Case gasket.

Had something similar happen to me a few years ago and it turned out to be the seal behind the rotary valve. Talked to a Ski-Doo mechanic about quick repairs because , according to the service manual, the engine has to be disassembled! Brought the unit to him and hour later was riding with new seal in place! He had a homemade seal installer that would allow installing the seal with the rotary shaft in place. Removed carbs, rotary valve and there was the seal, about 1" inside a recess. Check around.

I don't think it is the Rotary Shaft Oil seal, but I am not ruling it out yet. The thing is, the oil looks like it is leaking from the Crankcase where the two crankcase halfs are sealed together just under the waterpump. I believe that there is no gasket for the crankcase, they use some type of sealant? Any body know a quick way to seal it up with out pulling it apart?

Well to make a long post short, tomorrow I am pulling the motor and re-sealing the crank case. Know while I have the motor out, if the rotary shaft oil seal is bad where would the oil leak from and why? Is there any particular spot that the oil leaks from? Would the oil leak from the crank case if it was the Rotary Shaft oil seal? Sorry to be such a pain but if anyone can get back to me on this by tomorrow that would be great. Thanks

I would't be pulling the engine just yet, there is two seals on the r.v shaft(pump side) inner is oil seal outer is coolent seal. I would replace those seal's first. In between the two seals is a small drain hole in the block, thats were you should have the leak if the seal is leaking.
Good Luck

mr670, is there any way to check / replace the Rotary Valve Oil Seal with out disassembling the whole motor?