2601 running hot or paranoid owner?

[sunandsand]

2018 B2601, 265 hours.

Runs progressively warmer, at about 45 minutes, the progressively rising temp gauge makes me distinctly nervous, so I take a break for ten minutes and let it cool off, then repeat.

Seems to heat up when loaded (tall grass), then cool down a little, but not all the way each time the load is lightened (shorter grass). Notches up, but not back down as much each time. Seems on the verge of overheating, but not quite there, the longer I run it, the closer it seems to get.

I had been mowing Cogon grass, which is like trying to mow steel wool, bush hog notwithstanding. Had to stop every ten minutes to clean the grille, internal screen, and brush off the radiator. Watched the temp gauge, it never overheated, and when I got nervously close, it was break time for it and me to cool off.

Today I'm mowing just plain grass, not very tall and somewhat patchy - should be a cinch with this, right? Tractor runs warmer and warmer, when it gets to 3/16" from "hot" (about 45 minutes), break time.

Outside temp is 90 degrees, tractor has Kubota belly mower. Oil and water levels OK, screen and radiator clear, fan belt tension correct, all grease fittings on belly mower lubed, blades about ten hours old, tire pressures correct, brakes not dragging. Running at 2,100 rpm, medium speed, in 2WD. Radiator washed (external) with garden hose about two operating hours ago, no particular crud noticed - we have sand here, not clay. No damaged or dented fins on the radiator.

Coolant level in bottle is at the lower mark when cold (within spec), goes up progressively as tractor gets hot. Returns to lower mark when cold (parked for a while). No drips of oil, coolant, or green gold on the floor. No funny smells, but I can FEEL the heat just pouring off the engine . . .

Ideas?

Thank you and best regards,

Mike/Florida

 

[RjCorazza]

Nothing wrong with being cautious. In higher grass, particularly that which has gone to seed, I still would suspect material in the radiator or screen. Have you shined a light through the radiator? That can be revealing, even if it otherwise appears clean.

 

[sunandsand]

Nothing wrong with being cautious. In higher grass, particularly that which has gone to seed, I still would suspect material in the radiator or screen. Have you shined a light through the radiator? That can be revealing, even if it otherwise appears clean.

Will do that tomorrow. Afternoon clouds leading to thunderstorms, temperature dropped from 90 down by about 10 degrees. Tractor behaved a bit better, but I put it away because a tractor in an open field is not a real good place to be in a thunderstorm . . .

Stay tuned.

Best,
Mike

 

[big bubba]

smaller tractors have a low profile that pick up lots of chaff. a leaf blower on radiator in both directions helps, then periodic hosing when cool. compressed air maybe, but can distort fins, etc if not careful.
check air filter as well, again leaf blower is useful. you may have to blow out a few times each session.

 

[jyoutz]

Buy a radiator genie toolset and clean your radiator from the rear. It will flush out so much material that you didn’t know was there.

 

[Panik]

Not with a B2601, but I've experienced the same back when I was mowing 4ish acres with a 60" belly mower on my BX. Once ambient temps were in the low to mid-90's the BX would get to & run way hotter than expected, even with ensuring the radiator fins were clean....It's been a number of years, but I want to say the temp gauge would spike to near the 3/4's to 2/3rds mark on the gauge. It never over-heated but I have memory of having to once or twice a mow stop mowing and idle the tractor with the hood open for 10 minutes or so to bring temps back down.

Sounds like you've covered most everything in your description. The only two thoughts/questions I might add are:

- When was the last time you changed your coolant?
- Have you taken a look at, cleaned/changed the air intake filter recently?
- How do the the fuel filter(s) look/when were they last changed?
- This maybe BX and/or hydrostatic specific, but are all relevant cooling fans intact?

 

[JWR]

I have a BX2200 that ALWAYS runs closer to the red mark on temp than I like anytime that the outside air is over 90 deg and I am mowing medium to high grass using a 60 belly deck for more than a half hour. Have had this same thing with multiple BX2200's. I think it is the nature of the beast. In my opinion the water pumps are too small and/or move too little water when challenged by hot air temp and heavier loading. One of the BX2200's got worse (did actually overheat & spew coolant) and that was cured primarily by replacing the radiator. Fairly inexpensive to do.

 

[Milo]

Just a thought but you might try operating it closer to rated PTO rpm like 2,400 when mowing. When I had my L2501 I mowed meadows once a year (in Fall) so the weeds/grass was quite high, and I used a 58" flail. Always ran it at 2,400-2,500 rpm when doing this and when the temperature ever climbed to 3/4 or over that meant the radiator screens or radiator itself needed cleaned off. After that it was back to between 1/2-3/4.

 

[sunandsand]

Jury still out . . . rain every afternoon this week, I'll try to get back to this Saturday or Sunday early afternoon. Sounds like I need to revisit cleaning the radiator and consider new coolant.

Air filter is new, cannister cleaned, but I'll look at that again. I'll also try running it at 2300 and see if that changes anything.

Stay tuned, and thank you!

Best Regards,
Mike/Florida

 

[dadohead]

Yeah... I run my jd WOT when mowing. Higher rpm does not hurt a thing and lowers the torque load to the engine. All the time it is running the water pump and fan faster... does nothing but good.

 

[Milo]

I mistakenly thought 2601 was rated at 2,600 rpm but it's 2,800. Kubota recommends the 2601 run at 2,800 for mowing so I'd keep it there, no lower than 2,700. It'll be easier on the tractor and will mow better to boot.

 

[dodge man]

I’d also check to make sure the radiator is really clean. I also had a Kubota BX in the past and it tended to run up near red when hot out. My current JD never gets close.

 

[dadohead]

I’d also check to make sure the radiator is really clean. I also had a Kubota BX in the past and it tended to run up near red when hot out. My current JD never gets close.

I was an engineer at JD for 30 years. In the 90's when I had compacts, I put some of the competitors in the hot room dyno for testing. Back then, the Kubota models would typically fail in 6-8 min... they tend to run hot. Running WOT really helps.

 

[sunandsand]

Finally, finally got to this after the weather started cooling off and the two hurricanes went away and and and . . .

Removed the radiator - yup, all gunked up, clogged and nasty, couldn't see through about half of it!

Gave it a bath in engine cleaner (spray can) followed up by two cans worth of brake cleaner. Lotsa nasty crud came off, the fins are sparkly clean now. Hosed it off big time - yuck!

Put it all back together, filled the coolant (takes about two cups more than a gallon of 50/50 coolant from WalMart), cranked it up, runs nice and cool. Mowed for a little while until I got chased inside by the mosquitos . . . big ones - big enough to show on radar! Little ones - swarms - I thought they were going to eat me alive and then carry the tractor off into the woods and have it for dessert. Tractor SEEMS to be OK, I'll know better after county mosquito control does a helicopter fly-by and I can go outside and play again.

Comments on R&R radiator - easy job, three hose clamps, a dozen or so 10 mm bolts, two 12 mm, disconnect battery negative (just to be safe), access to the lower radiator hose is a lot easier with the exhaust pipe off - a 12 mm bolt on the bottom and a 12 mm clamp on top. A touch of anti-seize on the muffler stub for next time.

Have a drain pan ready for the old anti-freeze, it spatters. About a gallon comes out.

First time, about two hours total, add half an hour for cleanup (me, the tools and the floor), plus 15 minute break for diet coke (the only vice I am still allowed) and cool off in the A/C. Refill radiator and overflow tank, start and run, check level after ten minutes - OK. Will check it again tomorrow when the tractor is cold.

I have a LOT of mowing to catch up on.

Best Regards,
Mike/Florida

 

[jyoutz]

Radiator genie: air or water flush

https://www.amazon.com/Radiator-Genie-Cleaning-Efficiency-Radiators/dp/B01NAU8J6D/ref=asc_df_B01NAU8J6D/?tag=hyprod-20&linkCode=df0&hvadid=693713553307&hvpos=&hvnetw=g&hvrand=17535882191106240855&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9030404&hvtargid=pla-624415170167&psc=1&mcid=7a20470e5f46313bb50f21f26b36a957