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After my recent oil change I had pretty high oil pressure – around 0.5 MPa. I drove the tractor for about 4 hours. The pressure slowly dropped over that entire time. It got down to around 0.1 MPa and I stopped. It’s been sitting for about a month (on the side of a mountain where I stopped). I just tried to start it and it did start with no problem but now there is no measurable oil pressure.
I checked the oil level and it was about the same as after the oil change. I looked in the valve cover and I gotta say things looked a bit dry. I removed the oil filter thinking that it might be collapsed and not even bypassing. It was full of oil BUT I did note that almost no oil dripped out of the filter head (meaning I really doubt there is any oil past the filter.
So… My thought is clogged sump. Anyone agree? I didn’t have the chance to look at the time but how hard is it to drop the oil pan? Know that I have to do this parked on the level but on the side of a mountain. Any other ideas as to the culprit? Perhaps easier to check options? :scratch:
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I would place in a tee and a mechanical gauge on the engine and see what you have then. unless you have a mechanical gauge now but I assume it is electric factory one. Also what kind of oil did you put in it? It should be 15/40. The oil that can out when you did the oil change was there metal in it or was it just normal used oil, hope it did not look like a chocolate milk shake.
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I put Delo 400 in it. It’s a 15W40 oil. The oil that came out was black as coal but I didn’t see any metal bits.
Since I replaced the oil filter as part of this investigation, what I’m going to do is remove it again and see if it’s full of oil or not. Like I said, nothing dripped out when I removed the 1st filter. If the second one is dry then nothing is being pumped at all.
Thanks for the gauge check idea. I’ll see what I can do about getting another gauge to double check it.
If the engine really is dry, I’m impressed with how well it’s running!
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diesel engines are tuff but only to a point, my foton only had a idiot lite for the oil pressure and battery voltage so I put a gauges in the dash for voltage and oil pressure. The oil pressure gauge that reads in p.s.i. I ran copper tubing to it , most likely a mechanical gauge will never lie.
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I did have to replace the filter head when I did the oil change….and the oil pressure was originally very high just after the oil change…. hmmmm maybe it bypassed and got stuck….hmmm
I wonder if it is possible to check that theory first. That is way easier to remove compared to getting into the sump. Besides, experience has told me to always check whatever is was you did just before the problem started.
I’m pretty sure the oil pressure gauge is mechanical already. I don’t have it in front of me but I seem to remember a very stiff pipe feeding in the the back of the gauge (rather than a wire).
I thought the bypass valve just bypassed around the filter. Why would it bypass back to the sump? Wouldn’t it be better (in theory) to circulate unfiltered oil vs no oil at all?
Griz
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The bypass valve adjustment is located under the acorn nut on the filter head, but I think you have to remove the filter head to get at the valve itself. Not sure though, might all come out through the top. The bypass valve doesn’t go around the filter, it dumps back to the sump. Essentially it regulates the pressure going to the filter. The filter itself has a bypass valve to aid in cold startups and plugged filters but doesn’t regulate oil pressure.
Experience has also taught me to check the simplest and easiest things first. :yes:
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The gasket is directional but it’s pretty obvious that it only fits one way. You bring up a good point about the RTV. I put a little on the filter head side but nothing on the engine side. I basically just used it to hold it in place. Should I have put gasket sealer or RTV on both sides? Used none at all?
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So I attached a mechanical gauge to recheck the oil pressure. (FYI the gauge on the tractor is already a mechanical gauge but I guess it’s good to double check anyway). I ran the engine briefly but no pressure at all. Then I replaced the filter head with the old one and used the old filter. For one brief moment I cranked the motor over while the filter head was off and saw oil flow out of the head. To me that confirmed the pump was working at least a little bit. After re-attaching the filter I cranked it over and still no pressure. However I let it run for about 30 seconds and eventually the pressure came back up to around 35 psi. The needle was rock steady so that’s good.
Thinking I’ve had some success. I leave the external pressure gauge on and start to drive it off the hill. Over the next oh 20 minutes or so the pressure continued to drop down to around 10 psi where I stopped. It took me about 30 minutes or so to hike back to my truck and drive to the dozer. Leap frog with myself!
I started the dozer again and the pressure came up slowly to around 25 psi or so. Needing to get this POS off the mountain, I drove it a bit more. Again about 20 min and the pressure was down to 10 again. A bit of rest while I hiked back to the truck and again it came back to around 25 or so. Another dash (high-box 4th gear…what a ride!) and the pressure slowly dropped again.
So. Anyone? Slow loss of pressure. I’m thinking that the pump is getting hot and something starts to slip or a seal opens up. Cool it off and things bind up enough to pump again.
Griz
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Working with another gent with the same symptoms. He even changed out his oil pump with no difference, and also checked the filter head. The oil pump also has a bypass valve built in, but that was discounted too, and now the crankshaft bearings are suspect. He’s going to inspect the journal bearings and mic his crank. He has 1,200 hrs. on the engine but I suspect it ran with dirty oil for some time, but I know you are meticulous with maintenance so that wouldn’t apply.
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I am sad to say unless you get and find something strange it is looking like a engine disassm. to measure bearings . do you think that when you pull the belly pans the oil pan can come out so a visual inspection can be done with the engine still in the dozer. I have not worked on a dozer like these.
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