D 600 heat issue

[albertledet]

Hi, I'm looking for help with a d600. The engine runs 210 degrees under a load. I've checked the radiator, set the valves, checked the thermostat, fan belt radiator cap and no leaks.


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[cviola2005]

Is the machine running this temp when not under load?

Maybe the engine is under powered for what you need to do.

 

[Cglaza]

Whens the last time you flushed the radiator. My money is on heat transfer issue. Also, how are you checking the temp? Relying on a gauge in the dash may be leading you to believe that it is running hot. Just throwing that out there to check.

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[albertledet]

Is the machine running this temp when not under load?

Maybe the engine is under powered for what you need to do.

Thanks for the reply, if no load is applied the operating temp is 175 degrees.


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[albertledet]

Whens the last time you flushed the radiator. My money is on heat transfer issue. Also, how are you checking the temp? Relying on a gauge in the dash may be leading you to believe that it is running hot. Just throwing that out there to check.

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I have flushed the radiator / Preston flush kit. I installed a new temp gauge, I didn't trust the old factory gauge. It is my belief that I will need to advance the timing but I have not been able to locate a service manual. The little diesel requires the injection pump to be shimmed in order to advance the timing. Timing mark identification has been a problem also locating any information on the timing processes.


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[albertledet]

Thanks for the reply, if no load is applied the operating temp is 175 degrees.


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The engine sounds powerful enough to run the mower deck without bogging down also no smoke.


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[100 td]

Not sure what pressure radiator cap you have, if it's 8lbs, water boils at 233, 33% coolant 240F, so shouldn't be a big problem. What are the Kubota specs for it? YMMV (also depending on elevation, reduced boiling point)
https://durathermfluids.com/pdf/techpapers/pressure-boiling-point.pdf

 

[albertledet]

Not sure what pressure radiator cap you have, if it's 8lbs, water boils at 233, 33% coolant 240F, so shouldn't be a big problem. What are the Kubota specs for it? YMMV (also depending on elevation, reduced boiling point)
https://durathermfluids.com/pdf/techpapers/pressure-boiling-point.pdf

Thanks, it's a 9 pound cap, it's not boiling over but real close.


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[Cglaza]

I still think its a cooling capacity issue. Measure the temp at the radiator neck with an infrared thermometer. Depending on the outside temp, you may be running normally. Mine routinely runs in the 200 degree range when mowing on a hot day. Remember that even if a part is new, it does not mean a part is a known good part. Good luck.

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[albertledet]

I still think its a cooling capacity issue. Measure the temp at the radiator neck with an infrared thermometer. Depending on the outside temp, you may be running normally. Mine routinely runs in the 200 degree range when mowing on a hot day. Remember that even if a part is new, it does not mean a part is a known good part. Good luck.

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Thanks I will perform the test.


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[albertledet]

Thanks I will perform the test.


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Ok , so I checked radiator temp and flow again and immediately noticed flow in the radiator on a cold start. After removing the thermostat I noticed it was hanging up in the open position. I will change the new thermostat and try again.
Thanks again.


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[albertledet]

Ok , so I checked radiator temp and flow again and immediately noticed flow in the radiator on a cold start. After removing the thermostat I noticed it was hanging up in the open position. I will change the new thermostat and try again.
Thanks again.


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[albertledet]

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I also trimmed the hood to allow for cooling air flow. I noticed that if I cut grass with the hood open the temperature drops by 5 to 7 degrees. After trimming the hood I cut grass for an hour in 88 degree temperatures . The temperature gauge went as high as 190 degrees and stopped climbing. This appears to make a notable difference in temp. As the under hood temp drops so does the coolant temp. I think I will add an electric fan to lower the temp a few more degrees.


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[Russell King]

Did you clean the outside fins of the radiator?


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[albertledet]

Did you clean the outside fins of the radiator?


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Yes, I was out the radiator and screen every use.


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[kwfiggatt]

I have a G4200 that I swapped a D662 into and I have very similar coolant temps - in fact mine will get up to ~220°F when mowing fast on a hot day. I used the same radiator from the Z430 engine for the D662. I have a 13 psi radiator cap (from an older Honda Civic - at least that's what the parts guy said) and 220°F doesn't seem to be a problem. In fact, it probably helps engine efficiency a little bit.

This is an iron engine, and there aren't any thermal expansion issues with dissimilar metals like with an aluminum head. I work at an engine test lab and we regularly run some coolant temps as high as 240~250°F without trouble.

I did notice that the used D662 that I bought had a bigger fan on it, but it wouldn't fit with the radiator setup, so I swapped back to the smaller fan on the Z430.

PS What's the hose sticking out of the side of your engine for?

Have fun!

Kevin

 

[albertledet]

I have a G4200 that I swapped a D662 into and I have very similar coolant temps - in fact mine will get up to ~220°F when mowing fast on a hot day. I used the same radiator from the Z430 engine for the D662. I have a 13 psi radiator cap (from an older Honda Civic - at least that's what the parts guy said) and 220°F doesn't seem to be a problem. In fact, it probably helps engine efficiency a little bit.

This is an iron engine, and there aren't any thermal expansion issues with dissimilar metals like with an aluminum head. I work at an engine test lab and we regularly run some coolant temps as high as 240~250°F without trouble.

I did notice that the used D662 that I bought had a bigger fan on it, but it wouldn't fit with the radiator setup, so I swapped back to the smaller fan on the Z430.

PS What's the hose sticking out of the side of your engine for?

Have fun!

Kevin

Ok , the hose is a temporary repair. Lol the stripped coolant drain valve has been replaced and threaded. I have added an exhaust stack and a electric fan , in efforts to lower the under hood temperature. Under a load cutting grass on a hot day I now run 185/190 degrees.

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