Overheating issue, please help

   #1  

EddieWalker

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My 1998 New Holland 555E backhoe's hydraulics idiot light keeps lighting up, which indicates the hydraulics are overheating.

It happens fairly quickly, but not always at the same time, and the harder I run it, the quicker it lights up. Most of the time I just use it to bring a bale of hay out to the horses, and sometimes I can go there and come back without the light turning on, and sometimes it turns on half way there.

My first attempt at fixing this was replacing all the filters and all new hydraulic fluid. This worked great for a couple of weeks. Maybe 20 hours operating time. Then it started doing it again. My thought was that there was an issue with whatever fluid was left in it when I drained it, and that fluid plugged up my filters again. So I replaced all the filters again and put in all new hydraulic fluid again with zero change or improvement.

Here is a diagram of my hydraulic cooling system.

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The big filter is just to the right of the picture, about mid way. There is a square thing that connects to the filter bracket and there are two hoses that come off of it. One goes to the hydraulic radiator, the other goes to the tank. I took it off and didn't see anything wrong with it, but I didn't really understand what it does. I'm thinking its similar to a thermostat on a car engine. It's wide open going to the radiator, so I put it back on.

95782061_10222611798786358_4153167945700212736_o.jpg 95593590_10222611789266120_7804744137122512896_o.jpg


Today I took out the hydraulic radiator. It looks perfect. I put my air hose into one end and it blew out air from the other end. What did surprise me was that there was almost no hydraulic fluid in it. The way it's mounted is that it's above the height of the tank, so I'm guessing that what fluid is in there while operating, drains into the tank when the engine is off. That's my guess. Or is that a sign of the problem and fluid is not getting into the radiator?

95795016_10222611750425149_7975452560104357888_o.jpg


All the hoses are new, or near new. I've looked at touched every inch of every hose and there isn't any blockage from the outside. Nothing is crushed or kinked. I'm about to put the air hose into the line leading to the tank and see what happens. Then remove the filter and do the same on that line.

What am I missing?
 
   #2  

Diggin It

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Fully and completely untrained in hydraulics, but are you sure it really is overheating and you don't have a flakey sensor?

On the fluid level, is there a way to purge air? I had a Ford product where the top of the system was above the radiator cap. There was an extra step to purge air after replacing coolant that if missed would cause overheating.
 
   #3  

Agvg

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But have you measured the temp? Is it hot? It takes a lot of energy to heat the oil so quickly, any noise?
 
  
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EddieWalker

EddieWalker

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I have not measured the temp, or tested the sensor. I'll have to do that. Any recommendations on a good tester?


I just did a quick search on Amazon and saw this. https://www.amazon.com/Etekcity-Las...d=1588442707&sprefix=laser+tem,aps,323&sr=8-4


If I bought it, or one that somebody says is a better one to buy, where would I measure the temperature?

Does anybody know what the temperature is supposed to be so I can know if my hydraulics are too hot?
 
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EddieWalker

EddieWalker

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Just had another thought. If I blow air through the radiator, and it comes out without restriction, could it still be plugged up and not flowing enough to cool off the fluid?

Is there anything negative to filling up the radiator with paint thinner, or lacquer thinner and seeing if it dissolves anything in there? I have quite a bit of both. Carb cleaner might be better, but I don't have any on hand. I could buy some if there is an advantage to using it. or would something else be better to buy?
 
   #6  

radios1

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Just had another thought. If I blow air through the radiator, and it comes out without restriction, could it still be plugged up and not flowing enough to cool off the fluid?

Is there anything negative to filling up the radiator with paint thinner, or lacquer thinner and seeing if it dissolves anything in there? I have quite a bit of both. Carb cleaner might be better, but I don't have any on hand. I could buy some if there is an advantage to using it. or would something else be better to buy?
don't do that, the radiator is not clogged if air goes through it unrestricted!!. the lack of hydraulic fluid when you blew air through is is troubling, though, maybe it's not getting the fluid into the radiator. that would cause overheating right there!!.. that radiator should be getting hot, if not, it's not getting the hydraulic fluid into it!..
 
  
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EddieWalker

EddieWalker

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As of right now, I'm thinking that the only way to know that the radiator is good is to take it to the radiator shop. There was some sludge in the bottom of the tank when I drained it, which was also plugging up the filter inside the tank. If that sludge is blocking some of the tubes in the radiator, that might be my problem. Makes sense to me to have them do their thing so I know that's not the issue.

What else could it be? It runs great. There is only one hydraulic pump, and it powers everything. And everything is working great. Plenty of power, nothing at all wrong with driving it or using the loader or backhoe. It's just that idiot light that comes on after awhile, or almost right away. I hate that light!!!!
 
   #8  

dodge man

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I’d get one of those point and shoot thermometers and check temps. See if the cooler is warming up and working and maybe check a high pressure line somewhere.

Are you sure that light is only for hot hydraulic fluid and not something else too?
 
  
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EddieWalker

EddieWalker

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According to my owners manual, the light is for hydraulic temperature.
 
   #10  

dodge man

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Electrical tape fixes this kind of thing to. You know, a piece over the light bulb! The question is what should the temp be. I don’t know what normal is.
 
 
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