coop923 Posted November 12, 2014 Report Share Posted November 12, 2014 I mentioned this one on here a while back and got a couple responses, but I have a little more to add and I'm having trouble making sense of it. Here's the background: 2003 Silverado 2500 HD 6.0 145k. Started it up one morning and the low oil pressure warning chime went off. It had plenty of oil, and had just been changed so I thought it must be the sending unit. I pulled the sending unit and hooked up a mechanical gage. No oil pressure. Thinking it must be the oil pump. Tried pulling the filter just to see if anything was weird. Didn't notice any thing out of the ordinary. Replaced with a new filter. Re-attached the sending unit and started it up briefly. Found that oil had been pumped into the filter. I removed the oil filter and attached a mechanical oil pressure gauge at the filter mount. Found that I had 46 pounds of oil pressure (cold). While I was checking this, I noticed that the lifters quit ticking, making me think that I had oil pressure at the top of the engine. The warning chime did not go off while this was happening. I took the oil pressure gauge adapter off, and replaced it with the new oil filter. The lifters were ticking and the low oil pressure warning chime again went off. Now I'm thinking, "must be à blockage someplace". I removed the oil cooler line from the radiator and started the engine. In a few seconds it filled half of a juice jug. Also, no warning chime. As I was catching the oil coming out of the bottom of the radiator, I covered the end of the return line with my thumb. I had expected to feel suction, if anything. I was surprised to find that I had to squeeze fairly hard to keep my finger seated against the end of the oil return line. There was a certain degree of Air pressure coming out of the line. I was pretty sure that this line should be taking filtered, cooled oil back to the engine and can't figure out why I thought I felt air coming back in the opposite direction. I was hoping that maybe somebody on here could shed some light on this for me. Any ideas or suggestions where or what I should check next? Thanks. I reattached line into the radiator, and removed the bottom return line to see if oil would come out of the radiator. It did, and again no warning chime. I did not notice the lifters pumping up, but then again, I only ran it for five seconds or so. I reattached the oil cooler return line to the radiator and started The engine again to check for leaks. The low oil pressure chime went off immediately. Quote Link to comment Share on other sites More sharing options...
Cramer Posted November 12, 2014 Report Share Posted November 12, 2014 Fram filter? If so toss it in the trash and get a better quality filter. Quote Link to comment Share on other sites More sharing options...
BlueAKSSS Posted November 12, 2014 Report Share Posted November 12, 2014 (edited) Sounds to me like a failed O-ring between the oil pump and the pickup tube if its not making oil pressure. Also could just be a bad pump. That is just my first guess. Edited November 12, 2014 by Matt* (see edit history) Quote Link to comment Share on other sites More sharing options...
zachm89 Posted November 12, 2014 Report Share Posted November 12, 2014 The only thing that is stumping me is the fact that you have good oil pressure and flow when something is disconnected...whether it be the filter or a cooler line, whatever. But then when you close the system there is no pressure. PS: Don't listen to Sinr, FRAM filters are by far the best you can buy... Quote Link to comment Share on other sites More sharing options...
coal miner Posted November 13, 2014 Report Share Posted November 13, 2014 I like a k&n oil filter myself. Frams are junk! Quote Link to comment Share on other sites More sharing options...
Aldofashow Posted November 13, 2014 Report Share Posted November 13, 2014 (edited) I use the k&n myself gotta love the nut helps when it's time to come off Edited November 13, 2014 by Aldofashow (see edit history) Quote Link to comment Share on other sites More sharing options...
Cramer Posted November 13, 2014 Report Share Posted November 13, 2014 The only thing that is stumping me is the fact that you have good oil pressure and flow when something is disconnected...whether it be the filter or a cooler line, whatever. But then when you close the system there is no pressure. PS: Don't listen to Sinr, FRAM filters are by far the best you can buy... [emoji8] Haha Quote Link to comment Share on other sites More sharing options...
zachm89 Posted November 13, 2014 Report Share Posted November 13, 2014 I agree with using a good quality filter but I really don't see the oil filter being the problem in this case. Like stated, the oil pressure is there, but only when there is a break in the flow path somewhere. If the filter was the problem there wouldn't be any pressure or flow when the cooler lines were disconnected just like there is no pressure when everything is hooked up. I'm starting to think along the same lines as Matt that the o-ring for the pick up to oil pump might be bad and letting air get in and when you make the break in the line at the cooler or filter it is creating more of "leak" in the system than the o-ring. It might explain why you still have good pressure when something is disconnected, but it isn't pumping properly when the system is buttoned up because it is losing it all at the pump. Checking that o-ring is kind of a pain in the ass but might be worth it to check it out. Did you also use a mechanical gauge in place of the sending unit with everything else still hooked up? Quote Link to comment Share on other sites More sharing options...
Cramer Posted November 13, 2014 Report Share Posted November 13, 2014 Here is the oiling system passage diagram. Pressure at the filter with gauge, no pressure with filter. Either the bypass on the cooler mount block is blocked (which was checked and isn't) or the filter is blocking it up with either the wrong filter, crap filter (fram) or the outlet between the filter and sensor is blocked. You have pressure at the filter, oil and pressure at the cooler lines, pressure to the sensor with the filter off and gauge installed. You also mentioned you had no lifter tick with the filter removed. This means the pump is pumping oil and not aerating the oil. The filter is about the only thing that can be the issue. I have had a bad o-ring and know that you will more than likely have pressure, but the flow of oil won't be there. If the system builds pressure its either oil pressure (won't have a ticking at the lifters), the oil pressure is aerated (has oil and air going through the system and not allowing the lifters to pump up and causes a tick and or knock) or its straight up air ( will have major damage and the ticking is just the warning. The culprit is prob the o-ring. This is my .01 on this. Quote Link to comment Share on other sites More sharing options...
zachm89 Posted November 13, 2014 Report Share Posted November 13, 2014 Hey thanks for the diagram of the oil path Ryan...too bad it's so damn small! And what happened to your other .01? Can't give a whole .02 to this topic? Quote Link to comment Share on other sites More sharing options...
03SSBoy Posted November 13, 2014 Report Share Posted November 13, 2014 Hey thanks for the diagram of the oil path Ryan...too bad it's so damn small! And what happened to your other .01? Can't give a whole .02 to this topic? lmao Quote Link to comment Share on other sites More sharing options...
Aldofashow Posted November 14, 2014 Report Share Posted November 14, 2014 (edited) ? Edited November 14, 2014 by Aldofashow (see edit history) Quote Link to comment Share on other sites More sharing options...
Cramer Posted November 14, 2014 Report Share Posted November 14, 2014 (edited) Hey thanks for the diagram of the oil path Ryan...too bad it's so damn small! And what happened to your other .01? Can't give a whole .02 to this topic? OK OK! I'm sorry! I thought you were used to looking at little things so you'd have your magnifying glass with you. No I will not give my other .01 cause I'm a cheap ass that may need it later on. Here is a bigger pic for you. (tried on my phone last time.) Edited November 14, 2014 by sinr98 (see edit history) Quote Link to comment Share on other sites More sharing options...
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