Cat 325L, possibly ran low on hydraulic oil. Was working fine last time it was used. Shut itself down when the starter must have stuck on and ran the voltage down too far and it quit. New starter and started backup. Hydraulics are making an intermittent growling noise and no functions worked. Unfortunately it ran that way for 10 minutes while warming up before we realized what was going on. Oil level was quite low. Possible it lost prime while sitting with low oil? Refilled the oil and pressurized the tank in an attempt to get oil to the pumps. Remove the top pressure fitting to try filling the pump and the pump was full to the height of the flange. which is the height of oil in the tank. I depressed the test ports while engine is running, the lower port does have intermittent spurts of pressure, coinciding with the intermittent growling noises.. The top port just has oil flowing under gravity. No pressure behind it. Originally it was just aerated foamy oil coming out. Now clear oil. When it first starts up it will attempt to operate some functions. This does not seem to have a charge pump or pilot pump. I assume the pilot pressure must be taken off from the main pressure? If so do I need to bleed that circuit or manually stroke the pumps to build pressure in that circuit? While it was broke down waiting for the starter, I moved it out of the way a few feet with the dozer. Which did cause the house to swing slightly. Could that have any connection?
In order to help with the fix the Cat guys on here will want the machine serial number. Please post it
An 8Nk00260
See the attached procedure.
Thank you for posting the purge procedure. When I pulled the plug out, there was already boiled without air at that point. Now that I really pressurized the tank with air pressure. In the process of that, I realized that despite the tank being pressured, the oil coming out of the pump had no pressure behind it. So I pulled the suction screen out of the pump and found it to be blocked with ice. Problem solved. And I will draining oil next warm day. When we quit using it when the starter quit, ago the temperature was above zero. Next time we tried to use it it was well below zero.
You had to have a lot of water in the oil to form a block of ice to block suction. Would be good to investigate where water is getting in. You could have other water induced problems with the hydraulics as well. Hopefully nothing too serious.
If your suction screen was iced over, good chance your filters are full also.