Curt James
Member
Komatsu D21 oil pressure warning light at low RPM’s and idle - new behavior:
Hello, I've got a Komatsu D21P-6 dozer works great. It’s a 1992 Put all new engine fluids and filters in it when I got it, and have probably put 20 hours a month on it over last 2 years and about 80 hours on the oils. Unit has about 4000 hours total on it is my guess. When I use it at operating temperature for 1-4 hours the oil pressure warning light will come on at low RPM once it gets warm. When it starts (ambient air in the 70s) the light goes out quickly as expected at fast idle and does not come on even when at slow idle). After warm-up (temp gauge at normal) I start to lightly work the dozer (doing little more than walk it to the work site) and all seems fine. After 10-15 minutes of light work the temp gauge has climbed to mid normal (typical working temp for this machine in my experience), but when I idle down the oil low-pressure light flickers and comes on. If I increase RPM the light goes out. I continue to work the machine for 5 minutes or so more, but make sure the RPMs are high enough to keep the light out. I should mention that dipstick always indicates full of oil (although it is pretty black, as you would expect). In those 5 minutes it seems to me that I have to continually keep adding a little throttle to keep the oil pressure light out. This of course makes me very nervous. Restart after cool-down yields identical results. I'm am going to change the oil even though it is not due yet. My question really is: Does it seem likely that old oil and filter could cause this problem? I'm also wondering if the oil pressure sending unit may be at fault? What are the odds that the oil pump is actually producing insufficient pressure or volume once this old oil gets warm, or is it likely that the switch is becoming faulty as temperature climbs into 'normal' range? I"m sure the engine is not getting too hot in this timeframe. Obviously, I don't want to tear the engine down or do something major unless I absolutely have to. Is this behavior really unusual, and should I even worry about it as long as I operate it with sufficient RPM to keep the light out? The fact that it's not behaved this way in the past is disconcerting. Any other theories or suggestions? (fyi - I kind of plagiarized this because it is the same issue I’m having so I know it’s happened to others.)
THANKS IN ADVANCE FOR ANY HELP!
Hello, I've got a Komatsu D21P-6 dozer works great. It’s a 1992 Put all new engine fluids and filters in it when I got it, and have probably put 20 hours a month on it over last 2 years and about 80 hours on the oils. Unit has about 4000 hours total on it is my guess. When I use it at operating temperature for 1-4 hours the oil pressure warning light will come on at low RPM once it gets warm. When it starts (ambient air in the 70s) the light goes out quickly as expected at fast idle and does not come on even when at slow idle). After warm-up (temp gauge at normal) I start to lightly work the dozer (doing little more than walk it to the work site) and all seems fine. After 10-15 minutes of light work the temp gauge has climbed to mid normal (typical working temp for this machine in my experience), but when I idle down the oil low-pressure light flickers and comes on. If I increase RPM the light goes out. I continue to work the machine for 5 minutes or so more, but make sure the RPMs are high enough to keep the light out. I should mention that dipstick always indicates full of oil (although it is pretty black, as you would expect). In those 5 minutes it seems to me that I have to continually keep adding a little throttle to keep the oil pressure light out. This of course makes me very nervous. Restart after cool-down yields identical results. I'm am going to change the oil even though it is not due yet. My question really is: Does it seem likely that old oil and filter could cause this problem? I'm also wondering if the oil pressure sending unit may be at fault? What are the odds that the oil pump is actually producing insufficient pressure or volume once this old oil gets warm, or is it likely that the switch is becoming faulty as temperature climbs into 'normal' range? I"m sure the engine is not getting too hot in this timeframe. Obviously, I don't want to tear the engine down or do something major unless I absolutely have to. Is this behavior really unusual, and should I even worry about it as long as I operate it with sufficient RPM to keep the light out? The fact that it's not behaved this way in the past is disconcerting. Any other theories or suggestions? (fyi - I kind of plagiarized this because it is the same issue I’m having so I know it’s happened to others.)
THANKS IN ADVANCE FOR ANY HELP!