Kawasaki FD590 engine overheats.

DougDeere

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I have a Deere mower with a Kawasaki FD590 liquid cooled engine and it keepss overheating. I have checked fluid levels, changed the thermostat, flushed the cooling system, insured the core is not clogged with debris, the fan is blowing properly, and even bought a new impeller for the water pump, but I cannot get the engine to stop overheating. Even when the engine is hot, the air being expelled from the radiator is simply not very warm - when it certainly should be. What am I missing? Any ideas? Thanks in advance for your thoughts. I am debating removing the thermostat completely to see if this makes a difference, but it is a pain in the butt to dig down into the machine and remove it - although not nearly as bad as getting to the water pump.
 

Hammermechanicman

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Replace the thermostat if you have already replaced the water pump. If that doesnt fix it you are looking at either flushing the block or replacing the radiator. Which ever one is clogged or possibly both.
 

DougDeere

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Replace the thermostat if you have already replaced the water pump. If that doesnt fix it you are looking at either flushing the block or replacing the radiator. Which ever one is clogged or possibly both.
I have used jug of engine cooling system flush, run it until it wsa hot then flushed and re-filled with clean fluid. Is there something better on the market than standard auto parts store products? I am open to ideas. Thanks for your suggestions too.
 

StarTech

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Also make sure that cooling fins are clear of debris. They do tend clog up in dusty environments.
 

DougDeere

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Also make sure that cooling fins are clear of debris. They do tend clog up in dusty environments.
Fins are all clear - i use an airhose to blow all of it out when mowing is complete. One more crack with the descale fluid in the cooling system.
 

Scrubcadet10

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Is the fan working properly?
 

DougDeere

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Is the fan working properly?
Seems to be - good airflow as it exhausts from the radiator core. Bolts holding it in place are secure and fan is solid on the shaft and the blades are not broken or damaged in any way.
I suspect there is somethign fouling the block restricting water flow. I plan to test the core tonight with a hose to see how easily water passes through to insure it is not plugged internally. No visible signs of scale or build-up, but something is definetely wrong.
 

Hammermechanicman

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Not sure if you can reach it on that engine but run engine and feel the thermostat hsg and the hose between it and radiator. When thermostat reaches temp you should feel hose get as got as the thermostat hsg when the thermostat opens. If engine gets hot but hose doesn't here are in most likely order what could be wrong.
1 thermostat stuck closed
2 water pump malfunction. Broken gear in engine or broken impeller
3 clogged radiator restricting water flow
4 block plugged up
5 collapsed hose
6 pump air locked
 

Hammermechanicman

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When you changed the impeller on the water pump did you turn the engine over and watch the shaft turn to be sure the plastic pump drive gear in the engine is OK?
 

slomo

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Take that "new" thermostat and boil it on the stove. Take a coat hangar and suspend it off the bottom of the pan. Get a candy thermometer and verify WHAT temp it opens at or not at all.

A new part doesn't mean it's a new part.

slomo
 
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