G900 Hydraulic Oil Cooler.

Joe Pro

Member
Hello guys.

I have a G900 ( with closed center hydraulics ) and the hydraulic system runs very hot. I have rebuilt the pump, draft-3 point valve and replaced the filter. The reservoir and lines get very hot. I was thinking I could plum an oil cooler into the hyd case can line. Would this help me out any?
 
I don't know what is "normal" for a 900, the only closed-center Mo I've been around was a 1355.

That being said, typically, if a closed center system is running hot, there's a high pressure leak in one of the components/valves keeping the pump "in stroke".

From a start when it's cooled down, fell (better yet use a "heat gun") each component and note if any one of them warms up faster/sooner than the rest.
 
I'm sure that a cooler would help and I'm no help as to where to put it. In support of Bob, I back the pressure control way back and only adjust it up to a point where I need it to be for the task at hand and that seems to help to keep things cooler and quieter. I too should check for high pressure leaks.
CC
 
I have had problems with over-heating of the hydraulic oil on both my Vista closed-center system and my G-955. On the Vista (which I assume would be the same as your G-900) the oil would get so hot that the metal suction line to the pump would change color from energy yellow to prairie gold! It was a bad pump. On the G-955 it was also the pump. The G-955 has a cooler on it but that is not going to keep the oil cool if you really have a problem. We changed the relief valve on the G-955 first but that didn't solve the problem. When we examined the old pump you could really see the wear and why it was by-passing oil internally which gets it really hot.
 
Is it getting hot when not using the hydraulics or just when using the hydraulics?? If it gets hot when not using hyd check the compensator valve it is suppose to move the swash plate to a inline position so the pump piston are not moving in and out. If you redid the pump there would be no oil loss around the pistons. The oil cooler is plumed into the return line back to the tank. You don't want to have high pressure to the oil cooler!!
MMDEL
 
(quoted from post at 18:51:15 08/13/16) It is possible the gressen valves are leaking (very tight tolerances
required).

Could you elaborate?

I should have converted it to an open center when I had a system available to me.
 
Start from a cold system, start the tractor and run about 1/2 to 3/4 throttle(could run full to make it even faster) and take one of the infrared thermometers and check every place on the high pressure circuit to see where it is getting hottest the quickest. That is most likely where your problem is. Now, if you are running some sort of hydraulic motor such as a sprayer pump with the hydraulics you will almost certainly have to put some sort of oil cooler either on the tractor, or on the return line on the equipment. Anytime you have a high pressure leak, it will create a lot of heat fast. I remember you telling me that you had the pump redone, but just remember just because they have been rebuilt, doesn't mean that its done right
 
farmhick makes a good suggestion.But we don't all have thermal thermometers. Plug a high pressure gauge into one of the remote outlets, see if the regulator is set within specs. Take a jumper hose with a male outlet on each end and plug into a pair of outlets on the remotes. Then engage the lever for that valve and outlets. See if that eliminate the over heating.
MMDEL
 
Thanks everyone for the great information.

I do have an laser thermometer. I will check the system out. We have quite a collection of MM's and I have spent more time working on this G900 over the last few years then the others combined. This one gets on my bad side quickly, I love operating this machine an I dislike it so much that it is second only to my ex fiance.

At one point I did run a looped hose in a set of remotes, but I need both sets of remotes for my disc so that is out during operation.

I'm slightly concerned that I may have damaged the "new" pump the story goes I was working ground ( at 1 am ) and the rain was coming, a cylinder on the disc blew and i didn't know it and I lost most of the oil, I refilled the oil and lost it again before I figured out what was going on. The joys of working and farming full time! I can put a flow meter in the remotes as well as dead head a pressure gauge.

Does anyone have a tractor that they can compare temperatures to ? I know Curt Cook has helped me out before.
 

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