My Komatsu pc300lc-5 is running hot, slow and weak. I can´t run it at the HO setting and even in the general operating setting, I have to take it easy. Hydraulics are slow and a power is not where it should be. The hydraulic oil is dark in color and due for a change. The oil cooler is rusted and I believe that it´s not cooling the oil the way it should. Would this cause the engine to over heat as well? I know I can pay a high dollar mechanic to come out and figure this out for me, but I´m hoping for some guidance to eliminate what might be a simple solution. Any knowledgeable advice is greatly appreciated. -Joi
That's a tough one to answer via a computor . Yes it will make the engine run hot as the heat exchanger is acting like an oil heater and the hot air is being pulled through the radiator . Can you hear any cavitation ? Is the oil in the tank airated ? Could be a weak relief valve spring , stuck relief valve , hammer wires/switch short circuit causing hammer oil to be forced through bypass hose back to tank etc . Feel the temp of the hammer lines without using them , they should be cool . Dark oil is usually overheated oil , changing it without finding the cause is futile . How many hours on the machine ? How long since the oil filter was changed ? Is there any oil seeping from the pump suction line that would allow air to enter ?
You haven't stated how many hours are on this thing so I'll assume there are lots. The slow and weak part usually starts at the fuel strainer in the banjo bolt that holds the fuel line from the tank onto the hand transfer pump. Remove the bolt and you will find the strainer screwed into the bottom side of the bolt. You will probably find it plugged almost solid. The heating problem checks start at the cooler and radiator gap. Pull the bottom belly pan and let all the debris drop out of that compartment. Make a blow gun with a big hole to let lots of air stream through and blow the fins clean on the hydraulic cooler. You will be amazed at how much crap drops out. When you thing you have that clean go to the radiator side and do the best you can there. When all the air is clean go back to the hydraulic cooler side and start over. After that is done start the engine,max out the throttle and blow some more through the cooler with your air nozzle. When you are through put the machine back to work and see if the problem comes back in a short period of time. If it does, then you have a problem. Get a hold of an infrared thermometer and check temperatures on the inlet and outlet of the hydraulic oil cooler. You should see about 30 degrees F temperature difference. If not then you know what you have to do. There are instances where a pump can cause your problems. The hydraulic systems on those machines need to be tuned up about every 5,000 hours. That takes some gauges and a knowledgable mechanic and will cost you some money. The thing is to make sure the easy stuff is fixed before they come out. Good Luck and let us know what you find.
12,480 hrs at the moment. less than 500 hrs on rebuilt motor I don´t hear any cavitation. There´s no airation in the hydraulic oil. The machine does not have a hammer circuit. New hydraulic filter. No seeping oil from suction lines. I´ll have a better look at it tomorrow. Thanks for the replies.
My best advice is the same as John C has made here. Lack of fuel is the first thing to check out. Many Komatsu users has had the same problem with that cause.(we too) Not only the banjo, but the whole line and return to/from the engine. If its running hot, it might be a good advice to also check your thermostat. A machine that old might have a bad thermostat, that isn't opening like it should do. If its imported, it might also have a thermostat not suitable for your climate.(wrong opening temp) Rust on the oil cooler might not be bad, a rough surface make it a bigger surface, thereby giving it bether cooling.(thats why many coolers has cooler fins bent in a wave form) If its clogged by dirt, thats something different, then air dosen't flow across it and its not working as it is supposed to.
Thanks for the replies, everyone. The belt was slipping on the water pump:Banghead. I still need to clean out the oil cooler and radiator. There´s a significant amount of debris blocking the oil cooler. The problem is getting compressed air out in the field. I think I´ll get a CO2 tank to use as my comressed air source...small bottle, LOTS of air. Once this job is finished, it´s going to get a some needed maintainence.