Tractor overheats when mowing. No dealer actions fix it. Any ideas?

[Etced]

Replace the radiator cap.

 

[DonRybak]

I'm in agreement with those suggesting clogged fins of the radiator since the engine compartment was sprayed with hydraulic fluid. The dealer might have done a great job on cleaning the engine and engine bay but the radiator would be easy to overlook. Good luck.

 

[johncanfield]

There should be about a 30F difference between the upper and lower radiator hoses, I fought overheating issues on my rock crawler Jeep for a couple of years so I got quite familiar with cooling systems.

My Deere 4720 is a cab tractor, 66hp and about 56 at the PTO. Last week I mowed three straight days in about 92-95F ambient temperatures with my MX6 shredder. I was mowing grasses and various weeds to about 48" high, average height was maybe 24". Mow speed was 2.5 - 3.0 mph (2400rpm) and I took a full bite with every pass. I kept a close on the coolant temp, it never got close to the red zone. I did use the leaf blower every morning to clean out the grill and radiators before mowing.

 

[ptsg]

Not sure if it was mentioned before or not. But any chances of the thermostat being installed upside down?

 

[YLee Kioti]

After mowing and sometimes when starting up again after lunch I use the leaf blower.
When completely done I use the Genie water wand to flush out radiator.
May be worth a try to soak radiator with a foam type degreaser, then use a wand to gently wash out fins.
I keep water spigot open only half way to reduce water pressure and not bend fins. (well try anyways...ha...)
I use this one the Radiator Genie Cleaner Kit RG1002W RG1002-W RG1002.
Amazon has them and well good to wash out vehicle radiators as well. Amazing what washes out after years of driving.

 

[metalbender]

Made up a wand years ago while working on police cars used in rural locations. Used it to blow forward from the engine side. Talk about crap not hitting the fan. Have to wonder they ran at all with the airflow blocked so bad. Now the wands are commercially available, water and air.

 

[Oldpath05]

Strange, my temp gauge barely goes above this on the hottest days even when the radiator and screen has all kinds of dust and debris on it.

 

[pmsmechanic]

Strange, my temp gauge barely goes above this on the hottest days even when the radiator and screen has all kinds of dust and debris on it.

One thing I've learned in my years of being a mechanic is to never trust the gauge on a dash until you back up the position on the gauge with an infrared thermometer reading. Read right beside the temperature sender. Then and only then can you trust the gauge. For all you know that might be 200F. It probably isn't but you don't know for sure untill you check it. You might have two identical tractors running at the same temperature showing completely different on their respective temperature gauges.

 

[KWentling]

Since this all seems to be related to the oil cooler rupture/replacement, perhaps it is more of a hydraulic issue than an engine issue. The cooling air for the engine is drawn through the oil cooler first, so if the oil is overheated, the radiator air is going to be hotter than normal too. I would use the IR temp sensor to check the oil cooler temp also. Always blow all the dirt out of the radiator before using water or you'll just make mud you may have trouble getting out. What do the engine diagnostic codes indicate? I didn't see an engine temperature indication that would worry me much until the error codes pop up and it goes into limp mode, but I would want to verify that the gage it accurate. Where are you loosing coolant? Was a cause for the oil cooler rupture determined? Too much back pressure/restriction somewhere? Hydraulic oil filters been changed? Suction strainer clean? May not be a hydraulic issue but I would look there as well. Hydraulic oil temp would give you a clue if it is.

 

[the old grind]

I'm using point & shoot digital thermometers less since getting thermal cameras. One was <$200 (Seek Thermal) and clips to my iPhone. (i5 S is a 'drone' sort of, has SIM card but is no longer 'activated')

The little 'Seek' is great for service work, finding hot wires or weak wall insulation, etc and crazy much under a hood. I can use a 'gun' to get actual temps but the cam shows me where to check and has color palette options to relate to surrounding components. Using Apple's 'lightning' it can be connected to face to front or back on the phone.