DK35 hydraulic fluid light.

[mattman]

Tried a search couldn't come up with a hit.

Have yellow hydraulic fluid light coming on after couple hours of loader work. I don't run tractor very hard during loader work. I I use foot throttle. Manual says hydraulic fluid is getting hot. It is full of fluid and filter has less than 100 hours on it. Does anyone have the specs for at what temperature light is supposed to come on? There is two sensors by hydraulic filter figure one measures temperature and the other low pressure like if filter was clogged up?? Wouldn't think filter was clogged or light would come on at cold fluid temps when it would be thicker.

Anyone else run into this? I know the control valve for the loader gets hot to the touch, like can't hold your hand on it.
Going to bush hog here soon it will run constantly for awhile, so if it is going to get hot it will for sure running that long at pto rpm.

 

[VictorW]

I didn't know a DK35 had an indicator light for the hydraulic fluid getting past a certain temp nor a sensor for low pressure. Hopefully another DK35 owner can help. If you have been brush hogging, maybe the hydro fluid cooler, which is in front of the radiator, is full of grass, chaf, etc.

 

[DK35vince]

I didn't know a DK35 had an indicator light for the hydraulic fluid getting past a certain temp nor a sensor for low pressure. Hopefully another DK35 owner can help.

Thought all my DK 35 had was a light for the hydraulic filter.
No hydraulic temp. light that I am aware of.

If you have been brush hogging, maybe the hydro fluid cooler, which is in front of the radiator, is full of grass, chaf, etc.

The gear drive DK's do not have a hydro cooler.

 

[k0ua]

Hydraulic fluid light? Never heard of this... My DK35se does not have anything like that... pictures please.

OK, I stand corrected.. the DK35 has a hydraulic warning lamp. The new series the DK35se does not.

Apparently low pressure or over temp can be indicated by this lamp.

This lamp lights up yellow when certain
problems occur in hydraulic system.
This lamp lights up when the pressure in
hydraulic system drops down below a
specified value due to high oil temperature
(approx. 60 + 5°C) or blocked oil filter
carefully check the hydraulic system.

 

[Avondale]

This is news to me too. I will look into when I get home as I have used my bush hog for 6 hours at a time (sometimes on very hot days), and never noticed a light. I have seen my engine temp Gg rising which tells me to clear the rad screens ASAP.

 

[mattman]

My DK35 is a 2004 model and gear drive.

I have the same as was posted for the reason the light comes on. I need to find a better description and how to check which is turning the light on and what to do with it. Hydraulics work just fine, no squealing noises or anything like that. Need to figure it out before I tear something up.

 

[Avondale]

I have checked my owner's manual, which shows it on the dash map page and in the service manual wiring diagram which shows a "hydronic" light though the owners manual also talks about a blocked hydraulic filter. I have never seen the light come on, not even when turning the key from off to the run position. Not sure if it works or how to test the sensor/relay/light but will look into, later.

 

[k0ua]

And the next question would be, why did they not see fit to put one on the new DK35se model?

 

[Avondale]

Is it possible it is fit "for but not with" ? It may be a generic dash cluster but only used in certain models? Not sure when, but probably next time I pull it in for service, I will take a closer look at this.

 

[ritcheyvs]

On the old (non SE) DKs there are two sensors on the hydro filter bracket: pressure and temperature. The hydro pump sucks oil through the filter so a clogged filter will cause low pressure at the filter output. High temperature is self-explanatory. Either condition will turn on the instrument panel light. You may have a bad sensor. You may have crud in the fluid that eventually plugs the filter after running for a period but then drops off when the tractor is not running. You could have a defective filter. You may actually be overheating the hydro fluid. Normally, both switches should be open circuit. You can determine which switch is closing by pulling the connectors (one at a time) to see which one turns off the light. You can measure the temp with a non-contact thermometer at the oil filter. The manual is cryptic but it looks like the temp switch is supposed to close at 53 C and the pressure switch at 500mm (+-30) vacuum. Or you could just try a new filter if you haven't changed it lately.

 

[mattman]

Thank you that gives me some actual numbers to check against.

I don't think it is the filter clogging up. Would think the light for low pressure would come on when fluid was cold and thick. Filter has about 100 hours on it. Do you know if there is some kind of pickup screen on hydraulic pump. Need to find a flow chart of fluid.

Probably best thing for me is to start by changing hydraulic fluid and filter. Will look at what drains out and cut filter open for a look. My luck I will change fluid then bust a hose or something and loose 5 gallons worth.

 

[mattman]

Can you check that 53 Celsius ? Converts to 127 Fahrenheit which is low. Would figure at least 250 degrees before saying it was hot.

 

[mattman]

Well manual says if light comes on to change the filter. So fluid and filter change it will be.

 

[ritcheyvs]

Well manual says if light comes on to change the filter. So fluid and filter change it will be.

Good plan. If the light comes on again before you have a chance to change the oil/filter you might try this: Stop the engine and then turn the key back to "on." If the problem is over-temp (real or sensor error) the oil will still be hot and the light should come back on. If the problem is pressure, the light should stay off with the pump not turning. It might be useful to know of you are indicating a pressure or temp issue.

 

[k0ua]

Good plan. If the light comes on again before you have a chance to change the oil/filter you might try this: Stop the engine and then turn the key back to "on." If the problem is over-temp (real or sensor error) the oil will still be hot and the light should come back on. If the problem is pressure, the light should stay off with the pump not turning. It might be useful to know of you are indicating a pressure or temp issue.

Now that is thinking "out of the box" :thumbsup:

 

[mattman]

Changed fluid and filter today. Fluid was clean. Has magnets on both drain plugs and going into filter. Magnets were ok had some build up but nothing much too it. Did find wire pulled loose from vacuum switch. I may not have had a problem but the wire being off. Will find out soon I guess.

 

[alhll]

I have the same problem. I bush hog for about 1.5 hrs and my hydraulic oil light comes on. I turn off engine
and turn back on switch and light comes back on telling me it is overheating the oil. I had the oil and filter
changed twice but get the same results??? What is the problem. The shop said sticking valves and flushed
out the hydraulic system and changed the oil and filter. It did not solve the problem??HELP

 

[RandyT]

On my DK45S there is two sensors on the hydraulic filter. One for vacuum to check for clogged filter, and the temperature sensor. In order to turn on the dash light both sensors have to be tripped. In cold weather the cold oil will turn on the vacuum sensor but won't turn on the light because the temp is too cold. When running warm the temperature sensor will trip but won't turn on the light because with warm/hot oil there is enough flow through the filter to not trip the vacuum sensor. So in order to turn on the dash light the oil temp has to be above a certain temp and the filter would have to be clogged.

Had a fault vacuum/pressure sensor a few years ago and would act just like the above cases and turn on the light after running for some time period.