I’m having problems with my older 953 , the machine runs fine while warming up but it starts overheating and then slows down I changed the hydrostat filter 4 months ago with maybe 200 hours on filter pulled it today and it’s as black as can be ! Any suggestions would really be appreciated Thanks
An oil sample might show why it's turning black.
Hydraulics cooler could be fouled, may be time to get detail cleanings done.
Thanks for the response, I’m new to this but are you referring to the hydrostat cooler or hydraulic cooler? Fouled?
Hydrostat but is part of entire cooling group in back
Is this an oil getting too hot issue? Is there a hydrostat oil temp. gauge?
There is a gauge at the hottest it’s showing around 130 ,the actual engine radiator it’s the one that after awhile of running the temp gets up to 230 then I idle down and let it cool off once it cools off it tracks at normal speed
I would think of cleaning the outer fins on the radiator. I use foamy engine cleaner and a hot water hose. Some folks "carefully" use a pressure washer.
Thank you, the radiator is in really bad shape I pressure washed it and it still runs hot so I bit the bullet and ordered a new one , I’m hoping that after the radiator change and changing the hydro oil with getting samples taking it will improve
Do you have a picture of the service area after the cab is flipped open? Have you tried running it with the thermostat removed?
I’m not at the machine at the moment and no I haven’t but I put a new thermostat in it
A new thermostat should cover it. A machine as old as yours's could be all limed up. I don't think radiator shops boil them out anymore.
Make sure your exhaust is in good shape cause it will throw extra heat in the engine compartment
Yes, I replaced all the exhaust. I can’t find anywhere that will say what type of oil the hydrostat uses though?
Hydrostat? Hot? and black in the oil? Unh-oh... You might have bigger problems than you expect. The heat may be coming from internal bypassing in the drive pumps or drive motors. Heat in hydraulic systems comes from high pressure oil bleeding down into low pressure areas without doing any work. The energy has to go somewhere, and that somewhere is into heating the oil. The bypassing may be why you are getting heating when you use it for a while and it cools down when stopped and idling. I'll bet that the hydrostat oil cooler is liquid cooled, using engine coolant. So the overheating in the engine coolant makes it look like the engine is the culprit when maybe it really isn't. To check this out, you need to find a manual to see where to check the case drain flows at each drive pump and each drive motor. The higher the flow, the greater the internal leakage at that item. The manual will tell you what the acceptable flows are--as the pump or motor wears, the flows get higher and can eventually get high enough to overload the cooling system. Also, the black in the oil is carbonization, which is likely from the internal leakage as well. When the oil squeezes through the internal leakage, it can get super hot, enough to create tiny carbon particles. It seems to me that there are other signs of localized heating that will turn up in an oil sample test result, like the presence of certain gases that show up during localized overheating. That localized heating can also occur at other places in the drive system-for example, at a faulty pressure relief valve that isn't 100% closed or some of the shuttle valves in the hydrostat system. I sure hope this isn't your problem--Those hydrostat pumps and motors are kinda pricey and there really isn't a cheap way out of the issue. Keep us posted on what you find! Jon.
Maybe Cmark will see this thread or you could try PM him. He is the resident Cat hydrostat loader expert and has worked on these machines so may have seen this problem before.
Thank you for all the info , the hydrostat system looks like it is air cooled and the cooler is mounted next to the radiator. It’s definitely looking like a very expensive fix for sure
You said the hydrastat don't get hot on the gauge are you sure someone did not put some old engine oil in there it takes a 10 wt. use a hi quality not tractor supply or generic aw32 I have never seen oil turn black those radiators are marginal in cooling capacity I have a place that adds a few rows to help so if your radiator is not in top shape it wont do the job and make sure that the rubber seals are in place around the radiator. I have seen where the metal lines on the servos leak and slow the machine down