Kubota L4330 HST Running Temp and RPMS

[sorleski]

Hi All,

I'm in North Texas, high temps are in the low to mid 90s these days. I was mowing yesterday, 6 foot brush mower on my Kubota L4330. I was in some pretty heavy grass, and I notice that coolant is coming out of the overflow tank, dripping on the ground. The tractor did not overheat, it never went above 5 bars out of 8 on the temp guage. So, let me give you the details:

i've had this tractor for 7 years, never overheated, but I had it up to 6 bars on the gauge at one point.

• 2300 hours on it.
• I flushed and replaced the coolant 2 years ago, I put about 100 hrs a year on it.
• never replaced the thermostat, but I have one ready to go

my Questions:

1) When a tractor bogs down, could that make it overheat?
2) What RPM do y'all run when mowing? I am at 1800-1900, my theory is, it's pretty hot and I don't want to push it higher, but now I am wondering about the strain from bogging down
3) What is the normal running temp (mine has a series of bars, i think there are 8 total, usually once I warm up, i am at 5 bars. Is that normal range?

Whenever I run the machine hard, i let it idle for 10-15 minutes to let things cool down, and i rinse the radiator and oil cooler every week, or whenever I am done mowing (it's dusty here). At this point I am thinking it is the thermostat, but wanted to get some clarity on the bogging and the running rpms.

 

[number two]

Maybe post in Kubota Owning/Operating Forum for better advice from the experts.
If the tractor warms up as usual,the thermostat is normally not the problem.
Do you watch the temp display as you begin to use the tractor?
Good Luck!

 

[ruffdog]

my Questions:

1) When a tractor bogs down, could that make it overheat?
2) What RPM do y'all run when mowing? I am at 1800-1900, my theory is, it's pretty hot and I don't want to push it higher, but now I am wondering about the strain from bogging down

More RPMs would help because your fan and water pump run faster. If your engine bogs, your governor goes wide open trying to get your rpms back up. Run your rpms where you should for 540 pto rpm and be sure you blow your radiator out from the back side.

 

[redman135]

hullo sorleski, bogging down won't make the tractor vcerheat.
When doing pto work run at 540 pto rpm, that is what the brushog is desiged to work at and you get a better cut than running lower revs. There will be a place on your rev counter marked 540 to show you the correct engine revs.
Read the manual if in doubt.
Also read the manual to find maximun ambiant operting temp.
Radiator, put a torch in the back of the radiator (beside the fan) facing forward, go to the front, can you see the torchlight? if not blow the radiator out with compressed air(DON'T bend the fins), you will be amazed at how much dirt comes out.
As for dribbling coolant, check the level is above minimum, if you haven't already,and further comment I will leave to Kubota users.

 

[Smokeydog]

Run pto at 540rpm.

Blow your radiator(s) out. Blow your outer air filter out. We have to do that several times a year. Once one fall the B26 was low power and more black smoke. Mouse or chipmunk had packed the air cleaner housing full of marble sized acorns.

 

[big bubba]

Run pto at 540rpm.

Blow your radiator(s) out. Blow your outer air filter out. We have to do that several times a year. Once one fall the B26 was low power and more black smoke. Mouse or chipmunk had packed the air cleaner housing full of marble sized acorns.

yes to this....just because radiator fins look clean, give them a healthy blowout as well as the ft screen. & sharpen those blades esp for high growth. those are usually the culprits if the rest of the cooling system is ok

 

[Tinhack]

Run the engine RPM to get the correct RPM at the PTO. Lower RPM causes more heat just as too high RPM.

Also, you may have just over filled the coolant.

 

[sorleski]

So I did change the thermostat, I wanted to rule out that maybe it was sticking or defective in some way, and it's really not that hard to do. The one that was in there was a 71C, the new on I put in was a 71C, which converts to 160F. I ran it last night at faster RPM, and it seems to stay at 4 bars longer than in the past, but eventually got to 5 out of 7 bars on the heat gauge. It also cooled down quicker than in the past. So it's possible there was an issue with the thermostat, or I was running it too low RPM and it was getting extra hot. I will try sharpening the blades tonight as someone has suggested. I may have also had too much coolant in the overflow tank. I wish there was 1 answer to this, but it could just be a combination of things. Either way, it seems to run better last night. I think sharpening the blades will help too.

 

[rScotty]

What type of coolant are you using? My Kubota is a little older, and it uses the traditional old style green ethylene glycol coolant.

The special thing about pure ethylene glycol is that needs to be diluted with distilled water 50/50 for best cooling and best cold temperature protection.

About half the coolant on at my local auto parts store is marked 100% but some has already been diluted to 50/50. You can't tell by price, and I always have to check and sometimes read the fine print to figure out which one I'm getting.

 

[sorleski]

What type of coolant are you using? My Kubota is a little older, and it uses the traditional old style green ethylene glycol coolant.

The special thing about pure ethylene glycol is that needs to be diluted with distilled water 50/50 for best cooling and best cold temperature protection.

About half the coolant on at my local auto parts store is marked 100% but some has already been diluted to 50/50. You can't tell by price, and I always have to check and sometimes read the fine print to figure out which one I'm getting.

Yeah, i use the old style, it is a 2007 and i buy the concentrate and dilute it. But yes, i know, some comes pre-diluted and can be confusing.