Kubota G6200 over heating!

[Ryang6200]

Hey guys, i have a kubota g6200. I love the tractor but when i engage the PTO It over heats. I can barley make it through my 1 acre property without it over heating. I can use it all day without engaging the PTO and it’s fine. When i bought it i changed the coolant and it looked pretty muddy coming out so i flushed it with fresh water and additive and it didn’t help. I also replaced the water pump and the guy i bought it off of said he replaced the thermostat. My only other thought is the rad is plugged?

Thanks everyone in advance for their help!

 

[Utopia Texas]

Well, Go out and check the radiator to see if it is dirty between the fins and tell us what is up! If you can get the lower hose off put a water hose in the top and if the tubes are clean water should rush out the bottom.

 

[BruceP]

instead of REPLACING the mostly-copper radiator... consider RECORING. Any radiator shop can do this task.

Personally, I would remove the radiator and THOROUGHLY acid-clean and rinse it with garden-hose..... what have you got to loose before recoring it?

 

[motorhead]

Did the previous owner use the proper thermostat? I have seen where people put thermostats in backwards!
I second checking the fins to make sure they aren't clogged with dirt and debris. I use Purple Power, same as Castrol super clean and spray the fins good and let them soak. Then rinse out the fins OPPOSITE of the way the cooling fan works. So if a cooling fan is a pull through, from the outside towards the engine, spray the other way. BE CAREFUL NOT to bend the fins with high pressure hose nozzle. Spray straight through.
If you decide that the radiator needs to be flushed, I highly recommend buying some CITRIC ACID crystals and useabout 1.5 cups with clean water and let the engine run for an hour or so. Citric acid does NOT eat up water pump seals. I discovered this in Mercedes shop manuals as their way to flush cooling systems and have used it since. Rinse the radiator and block thoroughly after flushing. Be careful to not go over a 50/50 mix on coolant.

 

[dlundblad]

How hot is it running? Gauge hitting red and the whistler is going off or is it just running hot? Mine normally run just above the 3/4 mark when mowing. Is it losing any coolant between uses?

I would make sure the radiator is clean by reflushing. Amazon has 2 lb bags of food grade citric acid crystals. Dump the coolant, add the acid and water and run for about 20 minutes. Flush it out with fresh a few times and add coolant.

If all else fails, check the thermostat.

 

[Ryang6200]

I will look into everything you guys said and let you know!

Thanks everyone!

 

[Ryang6200]

Sorry for the late reply been working alot. I did what you guys said, cleaned out the rad etc. and ijust got done cutting the grass and it did stay cool for alot longer but toward the very end it started to touch the red. One thing i noticed is when i fill the rad up with coolant it doesn’t even take a gallon and it’s up to the cap but it has flow out of the bottom rad hose when i took it off. Any more suggestions?

Thanks!

 

[BruceP]

My G5200 (D600 engine) lists for holding 2.2 quarts.

I would think your D640 engine may hold slightly more.

I assume you have downloaded the service-manual already?
HINT==> http://www.kubotabooks.com/AutoIndex/index.php?dir=Tractor Owners Manuals/

QUESTION: Have you been cleaning the 'dust filter' still infront of your radiator EVERY time it starts to overheat? Mine needs to be cleaned about once an hour. Also ensure the air-intake is kept clean. (use brush and compressed-air to keep it clean)

 

[Jim L.]

ijust got done cutting the grass and it did stay cool for alot longer but toward the very end it started to touch the red

Even if you don't go into the red, if the machine gets enough hours of hot work, the cylinder head is in danger of cracking because the gasket will fail.

My advice is that if you can't find the problem, then change out the radiator. It will be a lot cheaper than changing out the head gasket and cylinder head.

 

[GeoHorn]

Forget the previous guy changed the thermostat and assume he did it wrong or with the wrong part. If you've cleaned the radiator fins inside and out, and fresh antifreeze, and thermostat is correct... then only two more things pop into my mind:
1- Lower radiator hose internal membrane is collapsing. New hose, missing inner-coil install, etc. should fix that.
2-Water pump impeller is spinning on it's shaft instead of spinning WITH the shaft, or is missing entirely. (I once removed a water pump from an inline-six in which the impeller was sitting inside the block completely off the shaft.)

On one other occasion I ran into a weird cooling problem where it was discovered a previous owner of a tractor had replaced the fan itself... with a fan which had reversed-blades... it blew forward instead of sucking air thru the radiator. It was apparently a part he'd rec'd from an unknown source and was designed for a specialty-purpose. THAT one was a real puzzle for a while.

 

[Richief]

I bought a G5200 last year and when attempting coolant flush and change, I found the petcock drain on the Block was completely restricted with rust scale, nothing drained from petcock. I drained coolant best i could with bottom radiator hose. I removed thermostat, bolted back on the water neck and filled with evapo-rust, ran engine for a bit, (only comes up a lil over the Cold mark with no stat) and went on vacation for a week. When i came back the block drain flowed freely and gray liquid came out. I have now flushed the coolant/evaporust mix out with distilled water and refilled with straight evaporust. I’m gonna run it mowing a couple times more, then get a new gasket and thermostat, flush and fill with Chevron Delo Coolant (same stuff I use in my 7.3L powerstroke, don’t use car coolant folks, as for why, google diesel coolant cavitation). My engine runs good, but showed signs of being overheated (coolant stains on radiator) so I think I averted problems by cleaning water jackets out, there are other rust disolvers too, i got this stuff @ decent price on amazon, seems to work good, claims it wont harm waterpumps and no need to neutralize because its not an acid.
Like was said before, drop bottom radiator hose and stuff garden hose in radiator fill and check for free flow. If radiator looks gummy inside I have had previous sucess with dishwasher soap and distilled water running without a thermostat for a while, i did do a neautralizer, warm cycle run, before the final coolant. And keep screen in front of battery compartment clean, just slides out upwards. Water pump turns free, Belts not warn, snugged tight, fan in good shape? Bar a bad thermostat, waterpump, restricted water jackets or radiator, she should run @ whatever temperature thermostat you installed.

 

[Cglaza]

I’m gonna run it mowing a couple times more, then get a new gasket and thermostat, flush and fill with Chevron Delo Coolant (same stuff I use in my 7.3L powerstroke, don’t use car coolant folks, as for why, google diesel coolant cavitation).

Cavitation is only a phenomenon associated with a wet sleeve engine. Our little tractors do not have wet sleeves thus no need to use that particular coolant. These tractors come brand new with green coolant and you are safe to use the green "car" coolant.

Sent from my XT1710-02 using Tapatalk

 

[D2Cat]

Yes, Cglaza is correct. Many think all diesel engines have the cavitation problem. Not so.

 

[North Idaho Wolfman]

fill with Chevron Delo Coolant (same stuff I use in my 7.3L powerstroke, don’t use car coolant folks, as for why, google diesel coolant cavitation).

That is not the case with Kubota Engines, they have dry sleeves and don't have such issues.

Standard automotive coolant is fine if not better than fancy collant.

 

[dlundblad]

I bought a G5200 last year and when attempting coolant flush and change, I found the petcock drain on the Block was completely restricted with rust scale, nothing drained from petcock. I drained coolant best i could with bottom radiator hose. I removed thermostat, bolted back on the water neck and filled with evapo-rust, ran engine for a bit, (only comes up a lil over the Cold mark with no stat) and went on vacation for a week. When i came back the block drain flowed freely and gray liquid came out. I have now flushed the coolant/evaporust mix out with distilled water and refilled with straight evaporust. I’m gonna run it mowing a couple times more, then get a new gasket and thermostat, flush and fill with Chevron Delo Coolant (same stuff I use in my 7.3L powerstroke, don’t use car coolant folks, as for why, google diesel coolant cavitation). My engine runs good, but showed signs of being overheated (coolant stains on radiator) so I think I averted problems by cleaning water jackets out, there are other rust disolvers too, i got this stuff @ decent price on amazon, seems to work good, claims it wont harm waterpumps and no need to neutralize because its not an acid.
Like was said before, drop bottom radiator hose and stuff garden hose in radiator fill and check for free flow. If radiator looks gummy inside I have had previous sucess with dishwasher soap and distilled water running without a thermostat for a while, i did do a neautralizer, warm cycle run, before the final coolant. And keep screen in front of battery compartment clean, just slides out upwards. Water pump turns free, Belts not warn, snugged tight, fan in good shape? Bar a bad thermostat, waterpump, restricted water jackets or radiator, she should run @ whatever temperature thermostat you installed.

The evapo rust is a good idea. Never thought of that.