520H Hydro Overtemp?

[Brian K WheelHorse 28]

The "idiot" dash light for "hydro hot" has come on twice this season. I'm not low on fluid and I was cutting grass for about an hour. It was 86 degrees when it came on a day ago. Any thoughts? Just hot? Old? Clogged filter? Changed all the fluid and put a factory hydro filter on the trans-axle last year. It's a '97 520H with the Eaton.

[tommyg 152]

Don't know much about the 520's, but I know on my Sunstrand, the aluminum fins on the pump can get clogged with grass, oil and debris and interfere with heat dissipation. Might be an option to check out anyway.

[ericj 1,578]

check you fan blade to see if it on the right direction. i dealer told me about it when the 520 i gave my brother started to do the same thing. we check my other tractors and then checked his and sure enough it was on wrong. no problem since repair., and yea it only happens after about an hour

 

 

eric j

[Brian K WheelHorse 28]

Thanks Eric - I'm not sure which way is right or wrong but I did replace the fan last year when I got the tractor as the old one was beat up.

[Red-Bovine 316]

My temp light also goes on on hot days near the end of a mowing session (about 1.5 acres). I recently did some work and noticed that there are a lot of places for grass to collect around the transmission, especially under the fender pan on the top of the transmission. Check that out and clean it all up. I gave mine a thorough cleaning. I will be mowing today or tomorrow in high heat and will see if that helped.

 

Red

[gwest_ca-(File Mod) 11,102]

The 523 page Demystification Guide page 3-38 shows the 113193 transmission temperature switch closes at 200 degrees. It also says normal operating temperature is 180 degrees.

 

 

Garry

[Brian K WheelHorse 28]

Thanks for the good info guys!

[ericj 1,578]

the fan if i recall is suppose to blow air in across the trans. when it is wrong it tries to pull the air out over the trans. and like red-bovine says make sure the trans is clean. grass and grease build up will cause overheating to, but check the tans air flow. good luck

 

 

ericj 

[gwest_ca-(File Mod) 11,102]

I don't understand this. If you remove a fan and turn it around and reinstall it still blows air in the same direction.

 

Garry

[Red-Bovine 316]

The direction of the airflow will not change by turning it around, but it will be more efficient in the correct direction. It should be more cupped toward the transmission.

 

Red

[ericj 1,578]

all i know was that i was told to check that on my brothers 520 and he did after looking at my tractors and he said it felt like it was pulling air out after flipping it over  it now blows air in and the temp light no longer comes on. so it does in my opinion make difference. but that's just my 2 cents worth. and what do have to loose by flipping it over and running to see what happen, you can always change it back

 

 

eric j

Edited July 6, 2013 by ericj

[Red-Bovine 316]

Just got done mowing about 1.5 acres in 88 degree heat and no Hydro Temp alarm today. Apparently the grass clippings were the culprit. I will certainly make cleaning this area out a routine maintainence item. There are many places that the grass can hide, so thorougly clean all arround the transmission and use a shop vac and/or air hose to help with the cleanout.

 

As far as the fan goes, Toro's diagram shows the concave side of the blade towards the transmission. This will give the best airflow over the transmission.

 

Red

[Brian K WheelHorse 28]

Thanks Red - it's hard to get to so I will have to hook my compressor back up. I will take the seat pan off after mowing season and really get in there good. Looks like it has a little bit of old caked on oil in the fins and I'm sure this isn't helping.

[Jeff-C175 7,203]

Brian, I don't know that I would wait the whole season to clean it out...  overheat not good!

 

I don't know about the 520s... but on my 175 I can have that fender off in about 10 minutes or so.  But even so, there's a big enough opening on mine to get in with the air hose and blow it all out good...

[Red-Bovine 316]

I was able to give the area a good cleaning using my shopvac and air hose without removing the fender pan, but it was hard because the grass was so packed in. I think blowing it out regularly with compressed air will be easier now that the old 20 year old packed in stuff is out. LOL

 

Red

[Brian K WheelHorse 28]

Thanks Red - I'll hook up my compressor next week!

[Brian K WheelHorse 28]

Hey guys - got in there and cleaned out as much as I could with my hand and a garden hose and no overtemp today! I got a lot of junk out of those cooling fins and it really seemed to help. Thanks.