Text of another thread on another site, hope it helps
A friend gave me a Kawasaki Mule, it runs great except for a major overheating problem.
It heats up...no circulation of coolant. When top hose is "relieved"--that is, when a clamp is loosened or the radiator cap cracked and burped--circulation begins. We detected this by feeling the pipe running below from the engine to the radiator. It stays cold...no circulation...until the air lock is broken...and then it warms. The radiator cap has been replaced, the hoses checked, the pump checked, the radiator flushed.... I have even driven it without a radiator cap...and yet it still overheats.
Any suggestions?
Thanks!
Does it have a cooling fan? If so, does it ever come on?
You may have airin the system. Also make sure your water pump is not damaged. Then again, your thermastat my be bad. If you dont want to check all this yoursel. Take it to your dealer.
Yes, it does have a fan but am now seeing that it only comes on after we have burped the air out of the system.
The water pump was checked by the dealer at the same time they installed the new thermostat.
Thanks. I believe what you found describes the problem exactly. As soon as the temps climb above zero, I'll try what your post suggests
Well, I've tried everything suggested and still it overheats. I removed the thermostat so a sticking thermostat can't be the problem. Until I 'burp' the upper hose, no water is reaches the fan switch so the fan never kicks on.
Without yanking the water pump out of the engine, is there any way to test to see if it's working?
Any other suggestions?
I know nothing on your mule but have know there was a car model that required the filling and flushing to fill their system under pressure. If not there was air pocket where the water pump could not pull the water.
My brother had a tractor wich did very much like what you are describing and a lot of his radiator was clogged. There was enough open that taking the bottom hose off let water come out but water hose in top was not large enough source to test the radiator flow.
I'm jumping in a little late on this, but there's something I'm unclear about here.
Are you saying that an air pocket keeps developing over & over, and this is consistantly preventing the fan from coming on?
Yes, that's what appears to be happening. Coolant never gets to the fan switch until the air pocket is released and then coolant starts flowing.
Well then Dick, I'm sorry to be the guy to ruin your day.
The only viable source of that much air, and the overheating problem is likely a blown head gasket.
The symptoms you are describing are a classic head gasket leak problem.
The cylinder compression is forcing past the gasket and pushing air into the coolant, since the coolant is a closed system the air is trapped there and just builds up.
Try doing a compression test on the cooling system. It may not show, buty I bet you are loosing pressure in the cooling system.
The easy test is to try running the machine with the rad cap loose, if the air doesn't build up, (you might even see bubbles or foaming in the water) and it doesn't over heat you'll have found the problem.
If the headgasket is blown, you might also know why you were "given" instead of "sold" a Mule, LOL.
Does a blown head gasket show up with water in the engine oil or is that a cracked engine or could it be either?
Ahead gasket can show it self in many ways. Combustion into the cooling system. Coolant into the combustion chamber and or oil coolant mixes.
Are you losing coolant? When you burp the system is it full or do you have to add? Where is the rad is the temp switch, top or bottom?
If you are not loosing coolant you may want to get it drained an vacuum filled. If that does not work you will need to pressure fill it.
Update... As I read the manual the other night...I know: a desperate last resort...I ran across something curious while looking for where the reservoir is. It has a required level. Hmmmm.... Well, I just found the reservoir...under the seat...and...it's empty. So I brought it up to level, topped off the
system at the radiator (at another filler cap at the front, NOT the same as the filler cap at the engine and res) and let it warm up. It does seem to be circulating. I ran it for a while, let it warm up and then drove it around pretty hard. No red light. No overheating stink.
It still seems like it's pretty hot. Do these engines run hot?
Had very much the same problem.
Could be one of these problems.
Coolant system is subject vapor lock.Work very hard to remove any and "ALL" air from the system.Lift the front very high if you have to. Get it all out or it wont be nice.
I had to find on the right side a very small temp switch/guage that did not work on mine. Two small plug in wires. Bypass them and see if your fan comes on. If so its your always off temp switch.
Sounds like you have air.----------- Jack it up high.
