Head gasket or worse ?

I have a problem with a 2016 Yamaha Kodiak 450 quad. Last spring it started overheating on a trip way back in the bush on my trapline. At first I thought it was the fan so I wired it direct. It kept overheating on the way out with the fan running nonstop.

It never got real hot because we would stop whenever the light came on. Couldnt see any water leaking but we were in wet swampy country. Anyway I've got it all torn down now and I did find a small leak in one of the rad hoses. Fixed that but still couldnt fill the rad. The water level just kept going down and no leaks that I could see. Finally pulled the dipstick and the crankcase is full of water so Im thinking ( hoping ) head gasket. Worse case Im thinking is cracked head. Has anyone ever torn down one of these newer quads ? How big of a job is it ?

Talk to the shop and see what they think and if you want to sink the money into it that’s totally your call

Might be a silly question but have you done an internet search to see if this is a common problem>

I dropped my Yamaha Grizzly 660 at the shop yesterday for the same reason. Plus differential is locked. Hoping the overheating issue is a plugged radiator or fan switch and not head or gasket. Good luck.

Doesnt seem to be a common problem from what I can tell. Wouldnt take it to the shop, this would be a DIY fix. At $120 @ hour I could buy a new quad for what it would cost to have them fix it.

I’m thinking if it’s leaking that bad without being under pressure it’s probably a cracked head. I would think bad gasket would be more of a seeping deal and usually only when it’s under pressure/running. I’ve never worked on anything that new. Hope ya get it figured out.

buy a factory manual. If you are mechanically inclined it shouldnt be to bad. The manual will tell you how to set the cam timing and have a list of special tools needed.

Water in the crank case sounds more serious than a bad head gasket.

Do a leak down test on Cylinder head

Thanks. You are probably right about the cracked head.

Water or coolant in crank case? You said running in wet swampy country. Did you get deep enough over the dip stick. 2 different issues, just wondering!

I would first buy the manual it’ll give you the best idea if you want to take it on, where it was getting hot that usually means a gasket but if you take the head off take it to a motor shop and have it fluxed for cracks.

No I didnt get that deep. I know its water because I checked the oil when I got home last year and again when I started working on it last week. The oil looked fine. Then I started pouring water in trying to find the leak. Found the small leak in the rad hose and fixed that. Thought I was good to go, but the water level in the rad kept going down but it wasnt coming out anywhere under the machine so thats when i checked the dipstick again.

I did read on another site that it could be the thermostat ....will check that tomorrow.

Wet swampy ground? Probably clogged the rad. Fan running all the time won't help the heat Probably ft the motor if you have water in the bottom end.

If it were me at this point I would do a compression check.

Good idea. Will do that

good luck with it...

Hey Dave sorry to hear your having problems with a 4 wheeler I 2 nd what Oh Snap suggested he beat me to it I wish you well with it .

Some of the newer snowmachine engines like Polaris, have a rubber O -ring head gasket that tend to go out and will fill your engine with coolant.
Look online for an exploded view of your engine see it it has those big O- rings. Might be the problem.

Gently pressurize the crank case with air, no more than a couple PSI. Best if you use a regulator, but can be done without. Listen and look to see if it is bubbling in radiator. If you are getting a large volume of air and bubbles out of radiator it is probably not a head gasket, look at water pump drive. Small volume air and bubbles it probably head gasket, cracked head or cracked block. But you said not able to fill rad as it leaks too fast. So on only that information I would think not head gasket. Will engine still roll over by hand? If it is head gasket it may hydrolock, I am guessing water pump drive. I have had water pump impellers come off shaft on both Polaris and Can -Am but not sure Yammerha is built.

I'm assuming there is antifreeze in the coolant? If so, and you have water in the oil you will have more problems than the headgasket (or whatever the leak is) to fix. If your going to fix it better go ahead and replace all the bearings when you have it apart. I've not had an issue like this on a quad, but in a vehicle if you get antifreeze in the oil you can about guarantee you will have bearing issues. I'm sure any four stroke motor will be the same. If it is just straight water and you get it cleaned out promptly it is not as bad as antifreeze, but still not good to have in your lubrication system.

I don't know how Yamaha is right now, but a lot of the ATVs and snowmobiles have gotten hard to get parts for in a timely fashion lately. Might check into that also if you need it soon. I know my 2016 Arctic Cat fourwheeler is down waiting on a new wiring harness that I order a month ago and is "supposed" to be in my the end of May.

Did it get cold enough to freeze it? One of my road race bikes froze overnight once, only allowed to run straight water. It popped a freeze plug out, was under the valve cover in head. If u had a cracked head or leaking head gasket I dont think it would leak so bad u cant fill the rad.