B7500 heating up

[Freds]

I don't remember which of the topics I stated some problems I was having with my tractor on, so I'll update here as I sort of got off topic from the original poster's question anyway.
After definitely overheating once and thinking it overheated for a second time after getting it back from the dealer for the first time (I was told the temp sensor had burned out from the original overheating), I put her to the test yesterday. She started bogging down a little and I noticed the temp ga. was halfway between the white marks, like most other people have stated, normal seemed to always be a little above the first mark, not halfway. I checked the screens and they were a little dirty, not what I would call clogged, so I cleaned them. This did not affect the reading on the ga. when I started running again.
I should mention the rpms dropped off from 2700 at full throttle to 2500, even with the PTO disengaged.
I kept on hogging and looked down once to see the temp ga. pegged, so I immediately pushed in the clutch and dropped the throttle down and the ga. started bouncing from pegged to the halfway point it had been running at. Okay, let's start hogging again and see what happens. The temp ga. sometimes would peg at hot and sometimes would drop back down to the halfway point, something definitely wrong here, even after they said they had replaced the bad sensor. Maybe the wiring went bad also? Either way, the rpms drop off after she's warmed up, like I said even if the PTO is not running and we are not moving.
What do other people's new B7500s run at and are there any ideas as to what the problem might be? Would a bad thermostat let it heat up a little and drop the engines performance down a little? I'd like a little "ammo" for when I talk to the dealer again, they must be closed for the holiday.

TIA for any responses,
Fred

 

[hazmat]

Fred,

If your getting rpm / power loss, I think you have a problem bigger than a bad temp guage. I wouldn't be running the tractor hard, maybe not at all untill its fixed. Things break when the water/coolant turns to steam. Not a good way to get 40 years out of old reliable.

Here is the easy stuff to check
Coolant leval
leaks in hoses/fittings
Thermostat (see if it "pops" when you heat it up in a pot on the stove) - Don't use Wifey's good cookware, there will be hell to pay.

Water pump could be bad, or something plugged up in the plumbing. Dealer should fix under warranty.

Good luck & happy tractoring.

 

[looch]

Mine has never been up higher than a 1/4. That's 90+ degree weather while bush hogging 4-5' high weeds.

You've got problems. Follow Hazmat's advice and don't place your tractor under load until it's fixed.

 

[snowman]

Freds;

My B7500 has heated up a number of times (under conditions that would cause it too), but I never lost RPMs, so you probably do have something else wrong somewhere.

 

[RoyJackson]

"Coolant leval
leaks in hoses/fittings
Thermostat (see if it "pops" when you heat it up in a pot on the stove) - Don't use Wifey's good cookware, there will be hell to pay."

Is the radiator and grill clean? There are warnings about this in my Operator Manual. It's never happened to me, but a friend with a Deere 850 has had overheating when his radiator and grill got clogged while 'hogging.

 

[TresCrows]

I suspect a bad thermostat, also, your coolant should be a mix of 50% antifreeze and 50% distilled water. If you have to much antifreeze the cooling capacity will be reduced. In other devices I have had in the past that were coolant sensitive I have dropped the mix to 30% antifreeze in the Summer. The antifreeze has other purposes than anti-freezing--it also lubricates the water pump and reduces boil over.
That your engine is actually slowing down worries me, are you sure it does that?
My BX would get warm (not overheat) in hot weather especially if the grill guard got full of lint but my 2410 I fear runs to cold. I hogged my field for 4 hours yesterday in the 90 degree heat and it never got above about 20% on the guage, maybe 30%. You better get to the shop before you ruin the engine. J

 

[crown]

My B-7500 has never gone up over 20% even when bush hogging in 90 degrees plus outside temps.

 

[Freds]

The engine is losing power. When the tractor had (guessing) less than 30 hours on her, the rpms would run slightly above the PTO line when running at full throttle. This was when the temp ga. was running no higher than 20-30%. Now, when the engine reaches the 50% range on the temp ga. (but this could still be messed up, as it bounces around sometimes) the rpms fall to the PTO speed line on the tach. I also notice that it's easier to bog down the engine and on those occasions when I can run with the speed pedal pushed in all the way, it feels like I am not going as fast. I suppose the tach could be malfunctioning also, but the other things are hard not to notice.
I'm hoping some other B7500HST owners will let me know what there tach normally runs at when full throttled with no load.
The dealer told me everything checked out okay on the dyno, but everything isn't checking out okay to my liking when actually using the tractor.

Fred

 

[RJS]

Well, mine is a B7500DT, I've never had mine at full throttle, but I often run it slightly higher than the PTO speed line when brush hogging with no problems. (even last wednesday)

I see your from NW PA, where did you buy the tractor?

 

[Egon]

Freds:
I'd take it back to the dealer right away. Lossing rpm may be an indication an internal water passage may be partially blocked or a gasket is leaking and one or more of the cylinders are overheated causing the slow down in the rpm.
With only 30 hours on it don't even touch it yourself. Let the dealer handle it and perhaps start asking to exchange it for another new tractor. Make sure all problems are documented and keep a log book for every time you use it.
If its a gasket or blocked passage ask for new tractor or engine as the present one may have suffered cylinder/ring damage that will not show up till after the warranty runs out.

Egon

 

[Freds]

RJS,
I have to run mine at full throttle to get slightly above PTO speed, that's why losing a few rpms is so noticeble. Seems like when I first got it, I rarely ran the throttle wide open. I got it from Rammelt's in Westfield, NY. How about yours?

Egon,
I wish I had kept some type of record already with the dealer signing something saying what it was in for and what he had done. I guess better late than never. I found it kind of odd that he has been doing warranty work on it and replacing parts without me signing anything so he can get reimbursed from the factory. I guess maybe it's different than warranty work on a car? He has a call in to Kubota (I was told) because he can't figure out why it's overheating and losing rpms. He says that everything checks out OK on the dyno. All I'm concerned about is that everything checks out OK when I use it. If he doesn't have an answer for me tonight I'm going to ask him for the loaner he promised. It would be nice to get another B7500 to compare to.

Fred

 

[cchoate]

I have a 7500hst with just over 12 hours on it. I'm going to be mowing on Fri so I'll kick her up to full throttle under no load and post RPM's results. I've never had temp gauge read higher than 30% even on hot days. I do clean everything after every time I use it using a compressor to clean radiator and screen ect...

 

[gusg]

I am also going to be mowing tomorrow with my B7500HSD so I will post results if I remember.

 

[RJS]

Freds

Mine came from Greenhill Farms in Cambridge Springs, close to Meadville.

I've had no problems with their service, but I haven't had any complicated problems either.

I think my tractor has around 60hrs on it now, I haven't been the best at keeping her up. I really should do the 50hr service soon, but with a new house I just keep finding more projects to do.

I hope everything gets worked out with yours.

 

[dgood1]

RJS

I think that you really need to make time for the 50 hr. service. I was told that they use a special break-in oil that gets changed out at 50 hrs. I think that possibly you may cause excessive wear to your machine's internal parts by keeping the break-in oil much past the 50 hr. mark.

Just my opinion and going by what my dealer told me.

Don

 

[Freds]

Well, they brought back my tractor today with a whole new dash and instrument cluster. I was told they ran it for 1 1/2 hours (and that's what the hour meter says now) and could not get the rpms to drop as it warmed up. Kubota had no ideas either. I'm supposed to call them and keep it running if it happens again. Unfortunately, I'm working on my new bldg. during their working hours and of course there would be no way to get a hold of them at night or on the weekends when I normally use the tractor. I was not offered a cell # even though I asked. Kubota told them that if the temp got up to the halfway point it is still considered a normal operating temp. I'll go hogging tomorrow and see what happens. If I start in the morning I may be able to catch them on their half day should the problem happen. It's been a good 15-20 degrees cooler in the morning and that might have some effect also.

Fred

 

[JRM **]

I just bought my B7500 , 750 hours and a overheating issue. Got it dirt cheap because of that , it had been to dealer 3 times with no joy. I replaced the air filter , no more overheating. I put a light inside of the filter and no light was visible through it. Totally plugged , just because the filter is cleanable does not mean it got checked.
I'm still going to change head gasket ,just in case , easy to do on this tractor.