How hot is too hot?

kspring61 · Jul 28, 2022

Starting to mow my fields down here in TN. A little bit warmer than when I usually do it later in the year but need to get all the fields mowed since I will be out west most of all Sept.
Anyways after mowing a bit my temps are going up on the my DK40SE, I have attached a pic of the temp gauge (wish these had numbers on them). I am assuming the 2 dots are in the 190-200 range but that may be a bad assumption, anyone have any idea what temp those dots represent?
Am I running it too hot?

I just replaced the overflow reservoir, plenty of coolant in the radiator, but the coolant is due to be changed. I doubt that would make it run hot because of old coolant, I think old only affects the anti-corrosion effectivity of the coolant. Am I right?

I did bring the tractor back up to the shop and blow out the radiator and cooler from the engine/fan side out, plenty of dust came out. Could it be the radiator needs cleaning? If so what is the best way? I do have a cleaning nozzle (low pressure) that I use on my motorcycles and ATV's that has a good degreaser/cleaner soap attachment that I could use to spray in there and try to clean it out and rinse with a hose. Any other ideas?

Sorry for the rambling but just thinking out loud and looking for some suggestions

Thanks

RjCorazza · Jul 28, 2022

Almost certainly the result of the dirt in the radiator fins. I blow the radiator out on my ZD mowers after every use, the tractor once in a while.
Blow out what you can, then flush the exterior with water. I've never used soap or other cleaners, but I suspect it would help.
They also make a water tool for radiators that appear very convenient.

DK35vince · Jul 28, 2022

I'm guessing the 2 dots represent normal operating temperature.
Your running a little high on temp, but not to bad.
Cleaning the radiator fins very well might help.

4570Man · Jul 28, 2022

Mowing will clog a radiator pretty fast. Blow it out and I’d say your problem will be fixed.

jmc · Jul 28, 2022

Every time I blow out my radiator fins from the engine side, I resolve to make a nozzle with a 90 degree tip in order to get a better angle on the fins. 30 years now, and counting...

Rockbadchild · Jul 29, 2022

Cleaning your radiator should do the trick, I usually air clean it, then I water spray it... I have seen old coolant clog up radiator (not on a tractor) and it was pretty old I don't think that your problem here.. I find the radiator get clogged up really fast when you mow with the wind in your back.

Thomas · Jul 29, 2022

As other said also check air filter.

xcgreene · Jul 30, 2022

Both DKSE tractors I've operated never really go above the second dot unless something is wrong.

That DK40se should have removable screens in front of the radiator to keep most of the mess out of the radiator fins. The radiator itself may look good, but if the screens are clogged, the air flow is not sufficient. Also something important to check are the vent screens on the hood itself, they too can become clogged and cause air flow issues, allowing overheating. Also check your fan belt for condition and good tension. If these "quick fixes" don't work, and if your coolant is on the level, then the thermostat may be a bit sticky, and is cheap/easy to replace while doing a coolant change. Thermostat element should start opening at ~ 160deg f and be completely open at 185deg F, with 8mm of height. (thermostat element can be checked on a stovetop in water, slowly bringing it up to temp.)

kspring61 · Jul 30, 2022

UPDATE: Thanks all for the replies.
I always clean the screens , both hood and the removable ones in front of the radiator, after every mowing session because of it getting clogged up with the grass tassles (seeds).
What I have been neglecting is blowing out the fins of the radiator from the engine side.
I did that and then used some ATV wash to do a good cleaning.
Went out and mowed yesterday and all was well, temps stayed right between the lines like xcgreene stated they should.

I will say when I blew it out and washed it, it was mostly just dust but enough of a layer of dust to make it heat up.
I'll be sure to keep doing this a few times during the mowing season.

MESSMAKER · Jul 30, 2022

It gets aggravating, but it is necessary.

Rockbadchild · Jul 31, 2022

At least you have a gauge so you can tell your temp ... My unit doesn't have one and its pretty annoying its just light up once its over heating .... I will have to install one.

Quickster2 · Aug 7, 2022

Interesting. My 2005 DK45 has never even registered the temp in between the dots. Always to the left (colder). The screen on mine is a PITA to remove and clean. I always spray low pressure water from the engine side towards the front to wash all of the fins out. Lots of crud each year near the bottom. I also wipe down the fan blades to insure they are clean and no major nicks on them.

hornett22 · Aug 13, 2022

Might want to blow out your air filter as well.

kspring61 · Aug 19, 2022

hornett22 said:
Might want to blow out your air filter as well.

Yea that gets blown out at least once every 2 weeks

DK35vince · Aug 19, 2022

Over servicing an air filter can be just as bad as underservicing

Servicing Your Air Filter – to Change or Not to Change? │Donaldson Engine & Vehicle

While new Donaldson air filters provide good engine protection, a Donaldson air filter that has been in service for a period of time works even better than a new one.

www.donaldson.com

Alien · Sep 10, 2022

Check your Fan blades. Mine rotted and flew away somewhere. The plastic is rubbish.

lman · Sep 10, 2022

jmc said:
Every time I blow out my radiator fins from the engine side, I resolve to make a nozzle with a 90 degree tip in order to get a better angle on the fins. 30 years now, and counting...