Frozen air bypass valve

[Turboflash]

Rock doc, et all - if you're coolant level goes down when you run the sled, and your oil level goes up, the coolant is going into the oil sump. I have first-hand knowledge of this problem. I know of only 2 sleds that had this problem. One was my 2017 ZR9000. The other was a Sidewinder.
Shortly after I got my sled brand new, I noticed coolant tank getting lower after riding it, and oil level going up past top line. I pressure tested the cooling system and, indeed, it would not hold pressure. I knew it wasn't likely a head gasket problem because the cooling system was not being pressurized. It has to be some other leak. Somehow coolant was leaking into oil sump (probably in head somewhere) and draining back to the sump and overfilling the oil tank. Sent oil sample to lab for testing. Substantial contamination of coolant in the oil!
I took head off and meticulously inspected everything. Could not find anything. Replaced head gasket and re-installed head with ARP head studs.
Re-built water pump too (just in case coolant was getting past seal and into oil that way).
Once back on the snow to test, problem was still there, even worse! So, for everything I had done, problem was even worse. I had missed something.
Went back to my shop to tear it down again. Again, cooling system was not being pressurized so I figured somewhere in the head, NOT near or in combustion chamber, the head had to be compromised. Took valve cover off and pressurized cooling system. Took out magnifying glass to inspect top side of head closely with pressure on cooling system. Sure enough, CRACK in head on left-side core plug boss. Had to have happened when "someone" installed the core plug at factory. The core plug is a tapered pipe plug. The further you drive the core plug in, the more outward pressure it exerts on aluminum boss. Either someone installed core plug with too much torque or maybe the head casting was bad. Either way, the left-side core plug boss had cracked. I could see coolant exiting the crack and running down the head surface into the drain-back holes which goes down into engine sump to be returned to oil tank. See pics. Notice the area on the core plug boss where I marked it. If you zoom in you can see the crack at about 3 o'clock. It goes across the boss and down the outside of it.
Bottom line: Cat warrantied the head (of course saying they'd never seen one before) and the gaskets. I did the work at my shop (don't trust my dealer to do this kind of work). Had to transfer all the valves, re-shim everything, and re-assemble everything. PROBLEM SOLVED.

Sorry for long post. I would take rock doc sled and do a pressure test on cooling system. Just because the dealer did a compression test doesn't mean it doesn't have the same crack mine did. Mine held compression too. See pics.

 

[rock doc]

This is very helpful! Thanks for taking the time to post all this info.

Just to clarify the mechanic did complete a leak down test of the cooling system and it passed. From what I have read this is not conclusive and sleds with a bad gasket have passed the leak test. Apparently in these instances the head has to be completely heat soaked to leak.

 

[Turboflash]

Yes, they can "pass" leakdown and still have bad head gasket. Also, I'd ask what does it mean to "pass" leakdown? Some assume a certain amount of leakdown over a certain amount of time is ok. If engine is cold, no amount of leakdown is ok. These systems are closed. If the test pressure decreases, something is not right/not sealed. On my engine, when I tested cooling system, I bet many dealers would have passed it. However, it only bled down a little bit in 15 minutes yet the head was cracked.
Good luck!

 

[rock doc]

Agreed. Unfortunately I have never done that type of work on a sled. I likely have to take it to a mechanic

 

[rock doc]

I have another quick question. Is it possible that the gasket between the water jacket/heat exchanger on the turbo and the oil cooling system is bad. Are there any other spots where the cooling system may cool the oil or is separated by a gasket that could fail? A buddy of mine that is a trouble shooter for Cummings suggest I pull the outlet lines off the turbo to see if pressure entering the cooling and/or oil system.

 

[Turboflash]

Coolant goes through turbo housing via a machined passage. There are lines going to and from turbo housing. No gaskets, just copper sealing rings or banjo bolts.
There is an oil cooler mounted to the front side of the engine. Oil passes through it on way to oil tank. Remember oil pressure is about 35-75 lbs depending on RPM. Cooling system pressure is about 14-15 lbs. IF the oil cooler was compromised, you'd have oil in the coolant NOT coolant in the oil as oil pressure is way higher than cooling system pressure.

 

[rock doc]

Coolant goes through turbo housing via a machined passage. There are lines going to and from turbo housing. No gaskets, just copper sealing rings or banjo bolts.
There is an oil cooler mounted to the front side of the engine. Oil passes through it on way to oil tank. Remember oil pressure is about 35-75 lbs depending on RPM. Cooling system pressure is about 14-15 lbs. IF the oil cooler was compromised, you'd have oil in the coolant NOT coolant in the oil as oil pressure is way higher than cooling system pressure.

Thanks for the info! I had heard the oil pressure is higher when the engine is running, but once it is turned off coolant can enter the oil. Having said that - is it possible for boost/air pressure to enter the coolant and/or oil system(s). I am see the oil froth up despite the fact that the level is fine once allowed to settle. The frothy oil seems to be entering the intake and picking up moisture. Not sure if some of the wet oil eventually recycling back, introducing a minor amount of moisture.

Recognize I am likely in denial that the head gasket is bad. Thanks for your patience - just trying to rule out as much as possible before we pull the heads.

 

[Turboflash]

Thanks for the info! I had heard the oil pressure is higher when the engine is running, but once it is turned off coolant can enter the oil. Having said that - is it possible for boost/air pressure to enter the coolant and/or oil system(s). I am see the oil froth up despite the fact that the level is fine once allowed to settle. The frothy oil seems to be entering the intake and picking up moisture. Not sure if some of the wet oil eventually recycling back, introducing a minor amount of moisture.

View attachment 152618

Recognize I am likely in denial that the head gasket is bad. Thanks for your patience - just trying to rule out as much as possible before we pull the heads.

IF oil cooler is bad (oil passages are leaking) then when engine is running there would be oil in coolant. When engine is shut off, oil pressure goes down to zero, there would still be oil in coolant from when it was running. So if you're not seeing oil in cooling system, then your oil cooler is likely ok.
Boost could only enter oiling system or cooling system if turbo is cracked internally. Turbo is cooled by coolant going through the main housing. Center bearing on turbo is oiled via the line coming from the head.
IF boost was entering cooling system, it would very quickly pressurize the cooling system and blow the hoses off somewhere or blow up the coolant tank. Keep in mind that at idle, you don't have any boost.
It would be very hard for boost to enter oiling system, it would have to mean the turbo housing is cracked near center bearing. Oil pressure is much higher than boost so you'd be having lots of oil going into turbo and could cause a fire. Your oil level would go down fast. Again, keep in mind at idle you have no boost but still good oil pressure. So even at idle, IF turbo housing was cracked, you'd have lots of oil getting into turbo.
-When you ride the sled, does your oil level increase and your coolant level go down? When you're done riding and it cools down, is the oil level higher and the coolant tank lower?
-Does your cooling system get over-pressurized? Does it push coolant out the overflow hose?

 

[rock doc]

I guess it must be a head gasket then. It was 1.5 inches too high after test ride. Next day unloaded it at the mechanic's garage and oil level dropped back down to normal. Not much coolant entering the oil if that is causing the moisture.

 

[rock doc]

No oil in the coolant either. Coolant not being pushed out the overflow. Maybe Going out the exhaust but no obvious sweet odor.

 

[Turboflash]

I guess it must be a head gasket then. It was 1.5 inches too high after test ride. Next day unloaded it at the mechanic's garage and oil level dropped back down to normal. Not much coolant entering the oil if that is causing the moisture.

I'm sure you know oil level should be checked hot? Run engine until it's at stat temp, shut off, wait about 5 minutes, sled level, check oil level. Should never be over the top line.

 

[Turboflash]

No oil in the coolant either. Coolant not being pushed out the overflow. Maybe Going out the exhaust but no obvious sweet odor.

Ok good, oil cooler is ok and so is turbo housing.

 

[rock doc]

Yes. level is checked hot. I think the oil is foaming up, perhaps due to the moisture.

 

[Turboflash]

Yes. level is checked hot. I think the oil is foaming up, perhaps due to the moisture.

That's not normal. I'd send in a sample of your oil for analysis. Most likely, coolant in oil. Wix has an on-line program if you don't have any other place to send.

 

[budman 1000]

Rock doc
I’ve been reading the posts here and couple things come to mind like is it possible you had a couple unrelated things happen that aren’t related to one another and your attributing it to one big issue which might not exist.

First thing I noticed on your post was condition you were riding in. We have experienced out west - Canada in extreme cold temperatures the air filter will plug with frost/ snow in 50 to 80 miles range. And I mean completely plug.

I feel you may have some amount of oily/water mixture in you air intercooler and this should removed and washed and dried out to eliminate that white oily goo in your air intake hoses. Or you may continue to have that white goo in your hoses no matter what else you do.

Another is you’ve got replies here indicating the oil level shouldn’t fluctuate.
In my experience it does on the Sidewinder and on My sled pretty much exactly how you described it. I park my sled in a heated garage same spot all the time. One day the oil is above full, next day below full, next day bang on and when it’s heated up the level is always higher. Which makes sense as you heat oil it expands.
I don’t feel you have coolant getting into your oil. Good advice from Turboflash is get it analyzed, any heavy truck shop in your area should have access to lab oil analysis.

One thing you mentioned was your coolant was dirty looking, that is a bad sign as your coolant even after many winters and mega mileage should appear clean.
My feeling is the coolant issue is all you need to concentrate on and not get bogged down by the intake and oil level. It only takes a pin hole leak somewhere and loose a cup of coolant and your sled will overheat.

Now here’s crazy story for you, one of my riding buddy’s worked for half his winter last year trying to fix his overheating issue on his 9000 Cat. Bleeding system in every way possible, tear his sled down, check it over. He’d start up his sled, warm it up, heat exhangers warm up nicely, jump on it test drive and 5 minutes down trail temperature light would be on. He did this process about three times over through out the weeks before he realized to switch his gauge to actually display coolant temperature. What he discovered was his sled was actually cooling down while driving and it was his low temperature light coming on.

Long story short he had a thermostat stuck open.

Sorry for the long read,
I really wish you well in finding out what’s going with your sled. These Sidewinders really are an awesome sled and I have been very impressed with mine.