cub 7260 overheating went way worse fast.

[electrycmonk]

I have the Cub Cadet 7260 with the Mitzu 1.3L diesel block I have cross posted this in the Mahindra forum......( byte tongue) I hope this is allowed.....
I have read all over the place over the previous 5-6 years that the engine is the same exact block. And as such with all those parts interchangable.....

these all have the 1.3L mitzu block as far as i can tell.

2310	25 hp	2002 - 2006
2516	25 hp	2008 - 2018
2525	25 hp	2008 - 2010
Max 25	25 hp	2012 - 2014
eMax 25S	25 hp	2017 -
1526	26 hp	2016 - 2018
Max 26XL	26 hp	2014 -
1626	26 hp	2018 -
Max 26XLT	26 hp	2018 -
2615	26 hp	2003 - 2008
C27	27 hp	2002 - 2006
2810	28 hp	2002 - 2006
2815	28 hp	2006 - 2008
2816	28 hp	2008 - 2010
3016	28 hp	2011 - 2021
Max 28 XL	28 hp	2012 - 2014

Anyone care to share any data or help out?

I'm looking at troubleshooting a overheated issue that seems to of gotten A LOT Worse....

I will update this later this week. I want to make a short video of the sound it makes when starting and when I can get it to finally start and run....

1st i need to make a you tube user ID so the video can be uploaded.

2nd the symptoms in short. it has had a mild overheating issue that slowly got worse over the years. so now I'm afraid its time to tear into the block and at least replace the headgasket and check stuff. the coolant gets purged from radiator when ever i get it running BUT< there is no coolant in the engine oil. I have not checked to see if there was any contamination in the hydraulic system. Not sure if that is even possible AND I didn't want to a$$ume this was a automatic no-go.


if this is ressurectible then I may also want to replace the clutch while i have it torn down and right now.... Messicks has some very interesting prices for clutch kit and stuff.

 

[ChasHM]

If it's just overheating you're worried about:
- is radiator clean (outside)
- is radiator clean (inside)
- is the radiator full (at least to the top of the fins) and there's a reasonable amount of coolant in the overflow tank
- is the thermostat broken shut (take it out and see if you still have an overheat problem)
- Is the water pump actually pumping (you should see movement in the coolant with the radiator cap off)
- is the fan belt intact and not slipping on any of the pulleys
- have you done a coolant flush - bottle of stuff from your auto store plus a couple of changes of water for coolant

No chance for coolant to get into the hydro circuit unless you (or somebody else) pours coolant into the wrong place. Considering the hydro fiill is between your feet when operating and the coolant goes in the radiator, highly unlikely.

"The coolant gets purged from the radiator when ever I get it running..." - You mean the coolant level goes to empty and thus is draining out on the ground somewhere???

Without more data, I'd wager it's time for a water pump replacement/rebuild and time to put in a new thermostat. Not yet time to pull the head.

 

[3gunr]

I have a 7260 and a 2810 mahindra and have never had overheating issues with either but as chashm has said their are lots of things that can cause overheating number one being a clogged radiator .

 

[electrycmonk]

So it’s midnight… I sincerely meant to give a bullet point style history of this topic…

So onwards in reverse timeline, of sorts…
Pictures will be take in daylight tomorrow as will that short video and setting up of the you tube account to upload these videos too.

Over the last 2+ wks now I have had to put this on the back burner. So got a few minutes test here and 30 minutes test there.

Mid sept. Troubleshooting the part number for replacement thermostats. Found 2 and they both failed to fit the machines lower lip that was to make it *level with the rest of the surface for the gasket to seal up.

Step one was to drain the radiator, block & hoses. Pressure washed the whole engine & parts before drain & removal of radiator.
Once removed the gasket was razor blade shaved off the face. Radiator was fully removed and used air compressor initially to get the buildup of dust & debris from between the coils. Then with extreme patience I used the pressure washer on the entire exterior of the radiator and also sprayed several times into the top and the flow tubes that are also ~2” ID.

Let air dry as I prepared the anti-rust fluid in the 5 gallon bucket again.
*****- I had done this once before; the late summer early fall before covid landed on our shores.*****

So at this point that 1st week has passed by & now into 2nd weekend. Reassemble all 4 of the hoses & radiator. Filled radiator with the fluid and let it drain into the engine block. Filled up a little bit some 6-7x before I tried a test starting.

The 1st round it cranked and sounded like it had one piston that was stiff — this is very out of character from the previous several years. Eventually got it to start and white smoke was lightly and then more so as it finally reached a rough 900rpms idle & I shut it off after maybe 90 seconds with white smoke and an obscene amount of air bubbling out from the radiator top port and splashed A Lot of that fluid out the cap and all pver everything. Shut it down for the day.

Next time was ~3 days later. Discovered that the coolant system seemed to of slowly leaked out from the mouth of the base for the top hose as well as the 1/4” ID hose fittings between that top port and the side of the coolant pump assembly. Filled the radiator up to almost the lip of the port on top.

Tried to start, it slowly cranked as if one cylinder was filled with some fluid? As it cycled the resistance to start lessened quite effectively. It eventually started and idled about 875-ish rpm’s and the white smoke returned for 2nd go-round. I shut it off after about 30 seconds because the coolant was gurgling out of the top of the radiator something fierce and lots of air bubbles.

Last Friday I did a little test and the engine seemed to start with 3x the usual effort to crank it. It seemed like one cylinder was filled with fluid in the combustion chamber. And it took 10-12 attempts of cranking it over to finally get it to fire off. It again pushed out white smoke and also eventually got easier to crank & finally fired off and idled with a lot of smoke with white smoke mixed in it. I noted that the radiator looked very low (almost dry) on fluid from the view with the cap removed. While doing all this cranking I layer my hand on top of the caps pipe and was able to feel air being forced gently through my fingers while trying to start & once it fired off & idled.

Once it finally fired off & radiator still seemed empty I left it at idle for quite a while; maybe 3 minutes - tops. Then I shut it off. Meanwhile through all this the engine oil level & consistency still the same. Not even close to raising or looking like chocolate milk.

Going back in time …about 3 months it’s starting to get close to overheating with much less time running. Waiting for it to cool off enough to open radiator cap and fill with fluid or just water. A few times and usually at least a cup or two of fluid was added and it was running for maybe 10-45 minutes before I’d see the tell-tale steam coming out through the screen on the side cover. I’d get off and go inspect and the overflow bottle was gurgling over flow like crazy and had plenty of bubbles. This was when I was doing mild dirt work in the yard. So it was “watch temp gauge” until it started to dance & then stop to let it cool off & then add water.

Going back to the early spring for a couple times mowing the yard it was running 30-45 minutes with the flail mower at roughly 2250 rpm’s (for PTO to be at almost max engine speed for 540 PTO to be at its max speed). The tranny was running in Mid 1 or Low 3 for cutting grass. Was not working it hard at all. And it was eventually getting hot and so I was shutting it off to check fluid with the boil over effect being visible.

With the summers 60+ days of 100+*F the yard didn’t need a mow for almost 3 months do tractor saw near zero use until I did that mild dirt work stated above.

Last year there were a couple times that the grass got very tall & thick so the mowing was at 2000 - 2250 rpm’s and tranny was in Low 1-3 depending on thickness of grass clumps to keep it spinning at peak speed for the flail mower. It would get hot and at the end of a hour or so I’d take a break and see a little overflow bubbling out. When it had cooled off from finishing the 2.5 acres it might need a few cups of water.

During the first two years of covid 2019/20 it was occasionally doing the steaming bubbling from the over flow bottle if it was run at the 2250-ish rpm’s for very long. If I stayed about 1750-2000 it was happy and on occasion it was gurgling out the overflow bottle. Again these years once cooled off it might need a cup or two of water.

Going back to 2018/2017 I had knee surgery at the VA and was dealing with the odd overheating issue. I believe I made a thread on this in the cub sun forum here - can’t go look while writing this long post… any who, used the laser thermometer on the block in many spots, hoses, radiator etc. and was noticing a oddity of temps around the place of the thermometer on the top front of the block. Replies in that thread *as I recall now* were suggesting I drain and flush n fill as well as replace thermostat. I bought this 5 gallon bucket of rust remover/metal conditioner. I drained the radiator & block completely. Filled it with this stuff. Ran it gently for several minutes to get all the air out of the coolant system then put the cap on. Per the directions it left it in for a week or so. Every so often fire it up and circulate it and warm it up. Then I drained it completely. Rinsed it with just water a couple times. Then drained it fully. Filled with fresh coolant and correct water added for mixture. It ran fine during that year with once or twice getting hot ( but, not into the red zone) and I’d slow dow the mowing or digging to the 1500, 1700, or stay about 2000 rpm’s and it was cooling back down.

Now, mind you I’m a stickler for keeping equipment clean & greased. Thanks to my Grampas, Uncle Dave & parents to a lesser degree for the teaching of preventive care & maintenance. So after every mowing or every other mowing or other use it was getting pressure washed. Inspected & lubed.

This year because of the heat & so little use it was washed off every several usages as it was not getting “dirty” enough to warrant a pressure washing. But greasing of zeros was still as needed.

Over the last 4-5 years I have started to replace hydraulic lines and top off the fluid in these two systems. Tractor with FEL & the backhoe’s self contained system. I have a few more hoses to replace yet, so I was going to wait on a full system flush (for each system) once I had replaced all hoses - likely next year. Meanwhile the filters had all been replaced at least once.

I’ve changed the engine oil & filter at least twice in the last 4-5 years.

So there yo have it.

My insomnia allowed me to write this on and off thru the night. I got at least 4 hrs sleep so far. It’s now 6:33AM.

I’ll post this now and see about getting another hr or so sleep.

 

[electrycmonk]

"The coolant gets purged from the radiator when ever I get it running..." - You mean the coolant level goes to empty and thus is draining out on the ground somewhere???

Without more data, I'd wager it's time for a water pump replacement/rebuild and time to put in a new thermostat. Not yet time to pull the head.

The coolant mix was actively gurgling over the top and out the open mouth the cap screws onto. And it was bubbling out quickly over the testing theses last 2+ week tests.

I’ll be removing the flail mower off the rear & FEL with neighbors help today to gain lots of elbow room for getting at the engine.

As for your bullet points.
V-belt has been A-okay all these 4-5+ years. Snug.
Radiator flush/fill & cleaning on outside see previous long post.

 

[electrycmonk]

Update with pictures.

In 1st & 2nd pictures (same picture) the Green outline is the hose in question.
The purple line is the approximate quantity of material that had clogged this 1/4” coolant hose & the brass drain valve .




The water pump came off very easily and it was spinning correctly AND had no slippage or play in the bearings either. So I sat it in the bucket of evapo-rust to soak for a day or two. Sorry no picture of the water pump itself when removed.















I plan to take the radiator to a friends shop and we will pressure test it with his test kit later this week.

 

[electrycmonk]

today is Oct 12th.... been distracted by several other tasks. decided to look at the oil one more time as i did try to just crank it with the water pump, radiator & hoses removed back on the 6th or 7th ... put the battery on charger overnight back on the 5th...

a good friend let me borrow one of his pressure test kits for the radiator but, i have not goten it to work just yet... getting the hoses plugged to hold a seal just right has not been a success yet. need to get a couple pvc caps to plug the hoses better.

it cranks but didn't want to try to fire off. Fine. I stopped there.

so this morning I pulled the oil dipstick... low and behold. it was *NOW* showing "fluid level 2+ times higher than full on it. AND it was looking like "chocolate milk got in the coffee." Back when i was troubleshooting and the coolant system was still installed and said the oil was still black, i did notice that the oil level was just a bit above the full line...

Yup. its at least a head gasket... still don't have time to disassemble the engine yet so... that will have to wait another day or so. Having read up on a fe threads here... it has the potential of being an engine replacement - at worst case; a possible cracked head, next least worse; head gasket replacement.... hopefully just this, at this point now.

 

[Ledgemere Farm]

today is Oct 12th.... been distracted by several other tasks. decided to look at the oil one more time as i did try to just crank it with the water pump, radiator & hoses removed back on the 6th or 7th ... put the battery on charger overnight back on the 5th...

a good friend let me borrow one of his pressure test kits for the radiator but, i have not goten it to work just yet... getting the hoses plugged to hold a seal just right has not been a success yet. need to get a couple pvc caps to plug the hoses better.

it cranks but didn't want to try to fire off. Fine. I stopped there.

so this morning I pulled the oil dipstick... low and behold. it was *NOW* showing "fluid level 2+ times higher than full on it. AND it was looking like "chocolate milk got in the coffee." Back when i was troubleshooting and the coolant system was still installed and said the oil was still black, i did notice that the oil level was just a bit above the full line...

Yup. its at least a head gasket... still don't have time to disassemble the engine yet so... that will have to wait another day or so. Having read up on a fe threads here... it has the potential of being an engine replacement - at worst case; a possible cracked head, next least worse; head gasket replacement.... hopefully just this, at this point now.

I hope you can get it fixed. I had a 7260 and it was a really good tractor. My Mahindra 1635 feels very similar though I think the 1626 is closer

 

[ruffdog]

Have them check for a damaged cylinder liner(s), head, and bent rods from being hydro locked. Good luck.

 

[ROUSTABOUT]

You probably bent a rod when turning it over. Water don't compress much, so things bend. If you can check compression, one cylinder may be low because a bent rod is shorter, less volumetric efficiency, less compression. If it's pushing water out before it gets hot, compression leaking into coolant. Add the white smoke, steam from burning water. Compression would have told you at the beginning. But it seems to always be the last thing people do.