Liquid Cooled Exmark Overheating

[MiksLawncare]

Model LZ22LKA604
Serial 229713

Ok, After turning the machine on it gets up to temp and stays ok if you only keep it on low throttle, when i open the engine up the temp. gauge starts rising all the way to the red. I replaced the thermostat 2 years ago so im not sure if i should try and replace it again? I also installed a toggle switch on my fan to turn it on and off, it helped a bit but it still wont keep the machine cool. I took a reading of my water and it is 140 degrees. I was wondering if i could remove the thermostat and just run the machine without it. I think this may solve my problem to see if i have a faulty thermostat. Would removing the thermostat be harmful to the machine during the summer time like it is now?

[FIXDISS]

If the water/coolant temp is at 140 that does not sound like it is overheating.Is the coolant moving thru the radiator ? Maybe the ascending unit or the guage is bad ?? Just my half fast opinion.

[MiksLawncare]

the water boils eventually, im not sure if it is moving because when i took the cap off the water started surging out so i needed to put the cap back on im really wanting to know if i can remove the thermostat with no harm to the machine

[Supertiger]

without the themostat the water will continously circulate and will not stay in the radiator long enough to cool off then the engine will overheat anyway. I think that maybe your water pump is not circulating the water after the thermostat has opened, or the thermostat is stuck open all the time.

[chesterlawn]

Check the wire connector that's up near the fan. I noticed my fan was cutting off, and when I jiggled the connector ( it looked fine) it would go back on. I cut that connector out and soldered the wires together, never had a problem since.

[ericg]

Does your cooling system have any leaks? You could have an air pocket that needs to be bled. The belt that drives the water pump could be stretched or the pulleys could be glazed causing the belt to slip when above an idle. If the water pump is working properly, with the radiator cap off, you should see the water move when you raise the rpm's.

Eric

[MiksLawncare]

when you say move, what exactly do you mean? the water flows out of the opening when the cap is off, it like surges, i see the pulley spins so my idea is that it is functioning, is there a possiblilty its clogged?

[ericg]

If the water is surging, it could be due to excessive temperature much like a car overheating and allowing coolant to overflow from the radiator. This could be from a closed or partially closed thermostat or from a water pump that is not moving enough water. In a normally functioning cooling system, you should be able to remove the cap and see the water moving along as it circulates from the spinning of the water pump.

[FIXDISS]

A couple of thoughts here; If that is a closed system then you have to get all the air out of it.Look for a bleeder valve near the thermostat housing or elsewhere in the cooling system. Also make sure the fins on the radiator are not clogged with debris. If you remove the cap and you are pushing water out of the radiator you could even have a blown head gasket or cracked head. Are you losing water from system ? Hope it is just air in the system and you can resolve it by bleeding the air out of the system. Just my half fast opinion.

[ericg]

Fixdiss, I agree and mentioned the issue of air as well. If this is a head gasket or cracked head issue then there has to be a loss of water which has not been mentioned by MiksLawncare. If the head gasket was shot, you would think that there might be smoke from the exhaust or water in the oil and or issues with fouled plugs. The fact that the issue seems to happen above an idle makes me lean toward low water flow which equates to loss of heat transfer.

[topsites]

Check coolant level.
Replace the thermostat.

[chesterlawn]

Did you get it fixed?