Mule 4010 Trans Diesel overheating

[NVBigBlue]

Hey guys,

I have a 2012 Kawasaki Mule 4010 Trans 4x4 Diesel that is having overheating issues.

One of the guys I work with was driving it and it died on him. We towed it back and I started going over things. Turns out it was dieing due to the engine overheating.

Before I go any further I should explain that I am currently deployed and access to parts and tools is extremely limited.

That being said, after an extremely long wait for new parts to arrive, I have replaced the following:

Thermostat
Water pump
Water pump drive belt
Radiator cap

When cold, if I start the engine, it will idle and warm up and the thermostat will open (I can feel the outlet pipe going from cold to hot). However, I never get hot water at the radiator. If I let it continue to idle, it simply heats up and starts to boil the water. Then it will blow water from the radiator and shortly after that I get steam. It's acting like the pump is starving for return water. Every time I refill the system, I am bleeding the air out.

I've pulled the radiator and disconnected all the hoses and using a shop vac, sucked all the lines and I get good flow on everything. This Mule does have an aftermarket cab heater, so thinking I had a big air bubble, I pulled the hoses from it and routed the heater line from supply to return, so that's out of the loop now. But I am still seeing the same problem.

I did find what appears to be pieces of a plastic bag (or something similar) inside both the radiator (inlet) and in one of the hoses. I have no idea how it got there as the Mule hasn't had any maintenance done to it since it left the factory (other than me during routine servicing).

I don't think it's a head gasket, as there is no water in the oil, and it doesn't act like air is being pushed into the cooling system. It definitely only blows water after the engine heats up to the point of making steam.

Also, I've tested the radiator fan and the temperature switch and both of those are working correctly. The fan never comes on because hot water never makes it across the radiator to the switch. There just isn't any flow. As a last ditch effort, I even swapped out the radiator with a new one (thinking that perhaps the plastic material may have been blocking the tubes).

My current thinking is that some of this plastic material is inside the block/cylinder head cooling passages and this is restricting the water flow.

As I said before, I don't have a lot of resources here. I have a basic set of hand tools, a shop vac (suck and blow) and a tiny compressor (1 gallon tank). I don't have running water. I'm having to use bottled water. I do have antifreeze for the Mule once I get this figured out.

I'll be pulling the new water pump back off tomorrow and inspecting the cooling passages as best I can. But does anyone have any thoughts on this? It's seriously kicking my butt...

Thanks,

NV

P.S. Here are the cooling system diagrams...

 

[bajabum]

Is the bottom hose collapsing? There should be a big spring inside to prevent this.

 

[NVBigBlue]

Is the bottom hose collapsing? There should be a big spring inside to prevent this.

No, it's not.

 

[SpudHauler]

1st check - I would try running it with no thermostat in the housing. That way you would get max flow.

2nd check - Remove all hoses and inspect their inner layer to see if it is disintegrating and flowing through the system or blocking it.

3rd check - If you had lots of water it would be nice to try a hose in the rad filler with no thermo and the return line off and then run water through the system and start the engine to check for return flow.

Otherwise, you my have to remove the head to check for passages that are blocked. If it was a plastic material, it may now be melted in place.

My thinking is that perhaps only part of the system is blocked, but with the heat of a diesel that would be enough to overheat the whole system.

 

[jlbota]

These engines are notorious for bad head gaskets.Maybe the pieces you see are gasket material? I wouldnt think a head gasket would come apart...but worth a look??? If you have that much of a blockage I would pull the head and check all the coolant passages and just replace the gasket. Much cheaper than a new engine. Hope you get it fixed....

 

[SpudHauler]

Not sure what happened to Nevada BigBlue, hope the lack of water didn't cause him to expire.

 

[NVBigBlue]

Not sure what happened to Nevada BigBlue, hope the lack of water didn't cause him to expire.

:laughing: :laughing:

No, I'm still here. I've just been doing a lot of traveling the last couple of weeks. Most of the places I'm going have limited or no commercial internet access.

At any rate, I've ordered a new head gasket and head bolts for the mule. Hopefully, this will resolve the problem.

I'll post up again after the parts get here and I get things changed.

NV

 

[SpudHauler]

:drink: That's great to hear, you had us a little nervous.

Not sure why the head bolts though. Not a usual requirement but can never hurt.

 

[NVBigBlue]

Hey guys,

Thought I'd give everyone an update....

Got all the parts in finally, and got the head gasket replaced. This seem to have fixed the issue. The Mule is running great and is no longer overheating, even with the temperatures we've been having during the day here (108 - 116 the last few days).

To answer the head bolt question...

No, the service manual doesn't state that they need to be replaced, and they aren't torque to spec then add X degrees. But since everything takes forever to get here, it was just safer to go ahead and get new ones. You know how it goes....the part you need is the part you don't have. :laughing:

I did use the new ones when I put things back together as a few of them had quite a bit of corrosion on the threads, and I don't have a wire wheel or even a handheld wire brush to clean things up with.

The procedure for changing the head gasket is straight forward, and it only took me about 3 hours to change it, taking my time.

It looks like the head gasket was leaking into the water jacket on all 3 cylinders. Mostly #1 and #2, but a little bit on #3 as well. The head is cast iron and there was no warping when I measured it. Everything cleaned up real good and went back together just as easy as it came apart. It was about $150 for all the parts (including shipping), but there are a couple of gaskets I didn't end up using.

The diesel engine on these is dead simple.... push rod valve train and solid lifters so no overhead cam or chain to mess with.

Here's a couple of pics for those that are interested...



Either because of the overheating issue (most likely), or just bad luck.... the rear main oil seal developed a leak at the same time it began overheating. I had to change the seal as well. I actually did this a couple of weeks ago before realizing the overheating issue wasn't just due to a failed thermostat...

Changing the rear seal is slightly more involved than the head gasket.... the entire converter system has to be removed...:confused2:




Oh.... I figured out what the 'plastic' stuff was in the cooling system. It's the lining on the inside of the water pipes that run under the Mule from the engine to the radiator. I pulled the pipes off to verify they were clean. I found quite a bit of this stuff coming loose from the pipe. I think it must be some type of anti-corrosion paint or coating. It had only come off on the ends near the engine. I'm thinking that maybe the steam from the engine overheating was hot enough to make it separate from the pipes. But who knows... I scraped off all the loose bits, so hopefully no more will come off.

Here's a pic of the stuff I originally found. I probably removed 3 or 4 times that amount from the pipes when I cleaned them....


(that's a 6 inch ruler for scale...)

At any rate, the Mule is all back together now and I don't have to walk everywhere.

Thanks for all the input and suggestions!

NV

 

[SpudHauler]

Great update.

Success always puts a smile on your face.

Like the new style jack you used. Make use of whatever is available. Great stuff.