| Author |
Message |
    
Jeff Conrad (Jwconrad)
| | Posted on Monday, February 03, 2003 - 06:16 pm: | 
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96 Disco 4.0, 101K
Almost a year ago my oil light came on while on a trail ride and after searching the archives I dropped the oil pan and discovered gasket material in the pickup screen like many others have. After cleaning and reassembly, the problem went away, until this weekend. While on another trail ride this weekend the oil light returned. I managed to limp it to a local shop with the light coming and going and lifter noise. We drained the oil and changed the filter. The light went out and the lifter noise quit so I made the drive home, almost 80 miles. Just before arriving home I noticed the oil light blink and go out but the lifter noise returned. I dropped the pan today but did not find any blockage of the pickup screen. What would cause the oil pressure to be fine then drop off causing the pressure sensor to fault? I have been told that the pump is either good or bad but not intermitent. Any suggestions?
Thanks for the help
Jeff |
Jeff Conrad (Jwconrad)
| | Posted on Monday, February 03, 2003 - 11:52 pm: |
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No one has any ideas on this? |
Norm
| | Posted on Tuesday, February 04, 2003 - 03:10 am: |
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Oil pump?
Have you done an oil pressure test?
---Norm |
todd slater (Toddslater)
| | Posted on Tuesday, February 04, 2003 - 04:56 pm: |
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Since you have the bottom off, go ahead and replace the pump...they are cheap. If you can find a high volume/press pump that would be even better. You could be lucky and end it here, however if you still experience the lights and noise after you button it back up, put an honest oil pressure gauge on it to elimate the poss of a faulty sender/light/lucusitis. If after all this your pressure is still low and you getting the dreaded noise...well its rebuild time. |
Paul T. Schram (Paulschram)
| | Posted on Tuesday, February 04, 2003 - 05:15 pm: |
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Ain't gonna be cheap to replace the oil pump on a 4.0. It requires replacement of the entire front cover and I believe it runs around $300. They are non-serviceable.
As for why this could be happening-when you had the initial clogging of the filter/intake screen, you scored a couple of bearings. Since then, you ran it under off-road conditions that generate more than the amount of heat generated while driving down the highway and the viscosity of your oil fell and the light came on. When this happened, you again did more damage to the main and by now rod bearings too. When the engine is at lower speeds, the oil pressure is not sufficient to keep the bearings wet, and the light comes on. As engine speed increases, the volume and pressure of oil increases and the light goes out.
My money's on a scrambled lower end. You gots two choices (well three, but it's not an option for me). 1: Boneyard engine, or new crate engine. 2: rebuild-you can do it cheap and dirty by just throwing a new set of bearings in it and buttoning it up and run it another 101K, or you can do it right and spend as much as the truck is worth and have a brand new engine that will last until the wheels fall off.
Me, if I had some time and a nice warm shop, I'd throw a new set of bearings in it, maybe a headjob, consider a new cam (I'm running the bill up here), and put it back together and run it until it breaks again. Boneyard engines shouldn't cost you more than $1500 with a 30 day guarantee.
Sorry to bear bad news, but I'm afraid it's probably warranted given the description of the problem and the conditions under which you continued to drive it, please don't take offense, it wasn't meant, just the facts as I see them.
PEace,
Paul |
Jeff Conrad (Jwconrad)
| | Posted on Tuesday, February 04, 2003 - 09:23 pm: |
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Thanks for the responses. Paul, no offense taken. You are only confirming what I suspected but did not want to accept. I am going to dig into it a little more this weekend. I do have another question though, why does the cover have to be replaced if the pump is replaced and if I only remove the cover to inspect the pump and the oil passages for any blockage, does the cover still have to be replaced?
Thanks again
Jeff |
todd slater (Toddslater)
| | Posted on Tuesday, February 04, 2003 - 10:12 pm: |
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Paul,
I am/was under the impression that you can replace and/or rebuild these pumps. I checked a couple of sources, XK's Unlimited sells a new pump gear and shaft for $54.37 and a pump repair kit for $37.37. Aluminumv8.com has an enhanced repair kit (pumps 25% more volume) for $60.00, $24.00 for the standard repair kit. Being ever the optimist and since Jeff has oil and grease up to his elbows already, I thought it was worth a shot. If it ends up it going down for the rebuild (I hate breaking that type of news) ...it's one less item to buy then.
Let me know if I am wrong about replacing/rebuilding the oil pump. |
Norm
| | Posted on Wednesday, February 05, 2003 - 03:15 am: |
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First thing I'd do would be an oil pressure test. Since you're getting the tapping sound when the light goes on, you're undoubtably losing oil pressure, so it would not be just a bad sending unit.
Like the 3.9 "B" motor, I believe on the 4.0 and 4.6 GEMS motors the oil pump is integral with the front cover, and is not rebuildable according to Land Rover. The earlier 3.9s and 3.5s had a separate oil pump that was rebuildable.
---Norm |
Paul T. Schram (Paulschram)
| | Posted on Wednesday, February 05, 2003 - 08:09 am: |
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Given the past situation, I don't think I'd even bother with the pressure test. This vehicle was run with low or no oil pressure long enough to have badly scored the bearings and perhaps even the crankshaft. The least intrusive means to determine the condition of the bearings is to pull the pan and then pull a rod cap and visually inspect. I'd be willing to bet half the cost of labor (at my shop) that we'd find significant bearing damage and impending crankshaft breakage if it is continued to be run.
Norm is right about the oil pumps. The front cover on the B model engines is slightly different from the earlier engines, as is the mating water pump. I'm not even sure you can disassemble the pump to inspect.
Peace,
Paul |
todd slater (Toddslater)
| | Posted on Wednesday, February 05, 2003 - 11:15 am: |
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You guys are right about the oil pump....don't know what I was smokin last night. |
Paul T. Schram (Paulschram)
| | Posted on Wednesday, February 05, 2003 - 11:48 am: |
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At least you could share!
Sorry, the Deadhead in me comes out once in awhile.
Paul |
Ron
| | Posted on Wednesday, February 05, 2003 - 01:49 pm: |
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Pull and look at a bearing as Paul sugests. Also check the switch as they are known to go bad.
Front cover is $$$, bearings are cheap to do mains, but if it is more than that wait until she blows and put in a new short block. At 101k everything is probably leaking and the valves probably have build up too.
If it were me, and it was only the light I would just run it if the first two check out. The other possible culprit is that the oil passages are clogged. You can pull the front cover and check/clean the oil pump quite easily.
Ron |
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