Adding hydraulic cooler to skid steer

[bdog]

I am running an auger on a skid steer and when the ambient temperature gets hot I have been having issues with hydraulic fluid getting too hot. I would like to add an auxillary cooler but am unsure how to connect it. The coolers are rated for pressures much lower than the operating pressure of the hydraulics.

I am guessing it has to be connected somewhere on the low pressure side of the system but I am confused as to where that is. Obviously the fluid reservoir is low pressure but what about the return line on the quick connects? It would be easiest for me to mount the cooler on the attachment and plumb it in after the Hyd motor between the motor and the return hose that connects to the quick connects on the skid steer. Is this a good location or would I have too high of pressures here?

 

[J_J]

The radiator for the hyd on my Power-Trac, is located just before the tank return, and has a fan and temp sensor.

It should also be after the valve on the OUT port.

The reason for this is if you will ever reverse the hyd motors for some reason, it will always be on the low pressure side.

 

[IceStationZebra]

The cooler should be the last thing before the oil goes back into the reservoir. If you put it before the return filter (as most skids do) you could blow the cooler or cooler hoses in cold weather.

Most machines put the cooler inline with the radiator. This is cheap, but there are two potential problems. First you will be lowering the engine cooling by some undetermined amount (size, fin density, etc.). And two, you could over-cool the oil in cold temperatures. The optimum solution is as JJ stated, a remote cooler with a temperature controlled relay. The next best thing is a thermal bypass for the cooler, so in cold temps the oil bypasses the cooler (a few coolers can be purchased with this already integrated.)

Good luck
ISZ

 

[bulldogshotgun]

the easiest thing to do would be to simply plumb it into the return side of your augers lines with a check valve after it so that you couldn't reverse the flow, unless your auger uses the high flow line in which case you probably can't reverse it. if you actually need to reverse your augers direction things are going to be a little more complicated.

 

[J_J]

If you put a motor spool valve on the auger for fwd and rev, the return flow will always be low pressure.

 

[bdog]

The quick connects on the skid steer go to a spool valve that is controlled by a person standing outside the skid steer. There are spool valves for rotation (forward and reverse) and up and down. So I am pretty sure the fluid only flows one way in and out of the skid steer.

I just was not sure what kind of pressures I might have on the return side between the auger and the quick connect. I have 3000 psi on the pressure side right before the auger motor so I was worried that after the motor it might be over 250 psi that the cooler is rated for and blow up the cooler.

I know at some point the hydraulic pressure drops to basically zero as the fluid tank on the skid steer is made of plastic but I was not sure if I needed to tie in right by the tank or if it would be possible to mount it on the auger attachment.

I would much rather mount the cooler on the auger attachment if possible because this is the only time I ever need it and there is a good spot to mount it on there vs not a lot of places on the skid steer itself.

 

[J_J]

Just check it out by installing a tee after the auger motor and insert a 3000 hyd gage in the tee. Could also try a 500 psi gage in the tee.

You can put the radiator on the auger, but

Should your radiator side QD ever unplugged accidentally while the auger is turning, the radiator will surly blow.

 

[MHarryE]

Oil differs from engine coolant in the viscosity change with temperature. If you run full return flow through the cooler on return you risk high pressures that can blow the cooler (depending on climate). Speaking from experience on a production machine where an engineer removed a pressure bypass valve we always had in the system because he thought it wasn't needed and the first failure was the first machine built with this change when a trucker was loading the machine on a cold Minnesota morning. Hazmat Team to the loading dock.

 

[bdog]

Thanks for all the info. Cooler arrived today. I think I will put a T as J_J suggested and make sure the pressure under normal conditions on the return is under 250 and provided it is I will install a 200 psi or so pressure bypass valve on the return line just in case the pressure ever gets too high it will just pop off and not blow up the cooler.

 

[J_J]

Did you get a fan cooled radiator?

The radiator /fan unit I have has a thermal switch to activate the fan when necessary.

You can get some cheap fans/radiators from the junkyard.

I believe all the Power-Tracs have fan controlled radiator coolers, and do a pretty good job of keeping the hyd fluid under control.