Backhoe Hydraulics Overheating Question

[EddieWalker]

Last summer my Ford/New Holland 555E Loader Backhoe hydraulic overheating temperature idiot light turned on. It was hot outside because this is East Texas in summer, but it had never overheated before. I cleaned out the radiators. There are three of them, and one is just for the hydraulics. I also replaced all three filters and all of the fluid. There was quite a bit of sludge in the bottom of the tank, so I wiped it clean with paper towels. The big filter inside the tank seemed to be clogged up with sludge too, so I thought that I had found the problem.

For a couple months during the Fall, cooler temperatures outside, it ran great without any issues. But now the idiot light is turning on again. Fluid levels are good. I'm thinking that there was sludge in the lines that I didn't get cleaned out the first time and it's plugging up my filters again. I have 3 new filters and hydraulic oil.

I'm about to drain it and change the filters when I noticed that the cap isn't venting. As I unscrew the cap on the hydraulic tank, I hear air sucking into the tank. The more I turn it, the louder the sucking air sound gets. When I take the cap off, there is a popping noise from all of the air sucking into the tank.

Can a cap that is supposed to vent, and not venting, be the cause of the hydraulics over heating?

I'm going to buy a new cap and see if that helps, but was hoping for some confirmation that it might be part, or all of the issue.

Thanks

 

[Billrog]

It certainly wouldn't help Eddie , positive pressure in the tank once it warmed up and negative when it's cooled off.

 

[EddieWalker]

It's $117 at Messicks!!!

 

[Billrog]

Fix the old one that price is outrageous.

 

[oldnslo]

Drawing a vacuum on your reservoir could (would) cavitate your pump and potentially cause it to become less efficient resulting in greater heat generation. Is the pump external or internal on the hoe? If external check the inlet oil temp Vs housing temp & also outlet oil temp with the pump under load. If the pump is slipping it will get warm to hot quick.

Also check to see if hot oil is going through the heat exchanger. If you have a heat gun check inlet Vs outlet oil temp. if oil was crudy possible there is a cooler by-pass that is stuck open. This could be built into the cooler so may have to take a few heat temps on the cooler to confirm oil is passing through the cooling tubes and not being by-passed.

And keep your fingers out of the fan cause if you don't it hurts ....

 

[Seven Gables]

I’m wondering if the inside of the tubes in your hydraulic radiator are plugged up with this sludge? May be a good idea to try and flush it with some sort of cleaner when you have the system drained, or bring it to a radiator shop and let them flush it out. I’m sure once it’s cleaned with a solvent it should be then flushed with the hydraulic oil you’re using to get rid of any solvent residue. Just a guess, I’ve never done it. Good Luck, Brian

 

[EddieWalker]

I filled the hydraulic tank up with new fluid yesterday and started it up. Everything worked great. Full power to the loader, backhoe, outriggers and driving it. Two or three minutes of running it and the idiot light went on. This was faster then before I changed the filters and installed brand new fluid.

Messicks has a parts diagram that shows a T after the filter that goes to the radiator, or back to the tank. This is what I'm going to look at next. I think it's kind of like a thermostat on an engine. They call it a Hydraulic Valve. So maybe it's temperature activated?

New Holland (555E) - TRACTOR LOADER BACKHOE (1/96-12/3) Parts Diagrams

HYDRAULIC VALVE,1-5/16" - 1285801509 $266.79

 

[BukitCase]

Eddie, I've never been around any newholland equipment but that "hydraulic valve" in the diagram may be a BYPASS valve, actuated by excess pressure - if so, and the heat exchanger plugs up, you would lose cooling AND generate more heat with the restriction caused by the (basically) relief valve (the tee in the picture)

Just from what you've said (and from my arm chair ) I think I'd be removing the 2 lines to the heat exchanger and making sure you still had flow capability thru THAT path.

IOW, I guess I'm agreeing with comments you've already gotten ... Steve

 

[oldnslo]

Eddie,
Getting hot in 2 or 3 minutes you definitely have something wrong. 3 minutes your system should hardly be warm.

Can you access the lines to the cooler without sticking your fingers in the fan? If yes check the hoses going into and out of the cooler. Are they both hot, neither hot, etc.

Same thing on the valve you posted. Check the oil temperature on all of the lines. If this is the cooler by-pass the line going directly to tank should be cool while the line from the filter and to the heat exchanger (radiator) should be hot.

Thermal heat gun is cheap compared to that valve it could point you towards the problem Vs guessing.

Really dumb question but... Have you checked the idiot light to see if it is operating correctly I.e. reading the correct temperature?

Do the directional control valves, lines, cylinders feel warm or hot when the idiot light comes on. Would guess the light would not activate below 150 - 160 degrees so it would be close to burning you if you touch something.

 

[nyone]

You should also make sure the over temp light is accurate. Electronics go bad more often than hydraulics on these type of things. Get your self a $20 HF temp gun.

Some hydraulic systems are made to have pressure in the tank. Have you talked to the dealer or looked up this is one of those systems?

At 3min until overheating I would be checking the sensor and not the hydraulics.