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Oil Light On at Idle

19K views 39 replies 10 participants last post by  LandRoverChesterCounty 
#1 ·
Hello. 03 Disco 130K. At idle my oil light is on or flashes a little. Got a$35 tester off Amazon. Cold idle 10psi, Cold 2K RPM 30psi, Hot at 2K RPM 30psi. Not sure if this even counts but a hot idle is around 5psi. I also think some oil is backing into the gauge and skewing the results for the worse. What do you think about these readings? I am going to replace the sensor.
 
#4 ·
I would expect at least 10-15 @ hot idle
You are aware of the oil pump problems that plagued 2003s I assume?
If the light is flickering with 5 psi it sounds like it is working properly.
How overdue is the oil change.?
 
#5 ·
It is suppose to be around 20psi at idle. The rev pressure of 30psi is not too bad, but issues will usually show up at idle, not at revs.

The most likely cause is simply that your motor is very worn. The number of miles on it does not really matter, it is how it was treated and serviced during those miles.

If you want a temporary fix, try a thicker oil. I would start with a 15W oil first.
 
#6 ·
Not sure if this even counts but a hot idle is around 5psi. I also think some oil is backing into the gauge and skewing the results for the worse. What do you think about these readings? I am going to replace the sensor.
It counts, sensor knows no difference between H & C.

Unless you're seeing oil inside the gauge display it should make no difference. What's min/max scale readings on gauge? Generally the higher the max accuracy on the lower end will be less. Slight chance gauge off but sounds like it may be time to look at oil pump. Some folks find changing to 20w50 boosts their OP until issue resolved.

FYI, D2 manual:
Pressure at idle - minimum 0.7 bar (10 lbf.in2)

Pressure at 2000 rev/min (hot) 3.4 bar (50 lbf.in2)

Low oil pressure switch opening pressure 0.24-0.41 bar (3.5-6.0 lbf.in2)
......
 
#8 ·
It counts, sensor knows no difference between H & C.

Unless you're seeing oil inside the gauge display it should make no difference. What's min/max scale readings on gauge? Generally the higher the max accuracy on the lower end will be less. Slight chance gauge off but sounds like it may be time to look at oil pump. Some folks find changing to 20w50 boosts their OP until issue resolved.

FYI, D2 manual:

......
The gauge is 0 to 140. Increments of 10. It starts cold idle at 15 then then when the air injection stops it goes to 10. Then when hot it goes to 5 at idle. Will mention this. This makes no sense but the original oil sensor was hand tight. I literally reached up and unscrewed it when I could not find the right socket. For the record the correct socket is 15/16th for the original sensor.
 
#9 ·
I'm confused. Did you check your pressure with your little Autozone gizmo or with a mechanical gauge?

You should have a substantial difference in oil pressure between cold and hot, unless you put a very light oil in it.


The '03 oil pump problems from what I understand typically happened fairly early on. It's hard to imagine that this truck, at 130K, is suffering from the '03 manufacturing defect. But the pump can be worn or have a cracked ring and cause this problem.

Aside from the pump, you have to think in terms of where the oil is going- it's either leaking out of worn bearings or the rocker shafts. It's unlikely that you're losing pressure from the cam/lifters. When I redid my '04, it had significant rocker shaft wear for having only 100K and religiously performed maintenance. That's the easiest place to start looking. If it was losing large amounts of oil in the bottom end, I would think you would hear some rod rattle when free revving it.
 
#12 ·
If you have an inch of deflection your chain is definitely stretched and should be replaced. As for the pump, any signs of scoring, cracking, discolouration etc. Are signs it is bad.
I would agree with others previous recommendations of dropping a couple bearing caps (main caps not rod as they are torque to yield bolts) and inspection for bearing wear.
 
#13 ·
I have nothing to loose at this point. I will pull the caps. Just so I get this correct. I pull the caps that hold the crank in?

Also I inspected the oil pump. There is scoring and some discoloration on the gears, housing and plate that holds the gear in. Really hesitant on dropping $500 on a new pump. Any one have any luck on a used pump for much less?
 
#14 ·
If your pump is scored it is bad, this is true of all oil pumps of this type. There is also a spec on the clearance between the housing and the gears, so if you buy a used pump be sure to check it to find out it is out of spec as well. $500 seems like alot of money, however how much is your next trip worth? Taking the family/friends on a vacation or other important event? When your truck strands you on the side of the road, or worse out in the middle of nowhere, suddenly $500 isn't that much money. Except now that is just the tow bill to get you home, not to mention the entire engine is now only good for anchoring your boat.
You can pull the mains and let the front of the crank hang by the timing chain, just think you will have that much more room to work with since yours is loose.
 
#18 ·
No - once you get the cover off its a simple knock out the old one and tap in the new one. I have not had a problem doing it and they dont seem to leak - you have a bit of play ion how deep you can tap the seal into the housing so just tap it in to a point where its away from the previous wear groove and you should be good to go.
even with the dowels there is a little play nin the front cover so when you reinstall get the cover on and the bolts in then tap the crank pulley in and wiggle the cover a little to settle everything in then tighten down the bolts.
As has been said already if you pull the front cover replace the timing chain and gears - they can be had relatively cheaply.
cheers
Barri
 
#19 ·
First of all thanks for your help. I checked the tolerance of the pump gear to the housing it sits in. It is more then .004 gap. Now onto the bigger issue. I pulled two main bearing caps #1 and #2 . The caps that hold the crank in. Things do not look good there. What do you think? Can I just order new bearings and call it a day? Do I also replace the ones on the connecting rods?
 

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#20 ·
You can try to plastigage the bearings and see where you're at on clearance. Typically you'll see more wear on the journal. Not necessarily big ugly grooves, but a reduced diameter. It usually shows where the edge of the insert hits the journal.

Rod bearings typically will show more wear than the mains, as a result of how they're lubricated.
 
#21 ·
I have rebuilt a lot of engines professionally and any copper showing is wore out. If you plastigauge it it will be out of spec. I would replace rod bearings as well, depending on the condition of the crank you may be able to use stock sized bearings. Be sure to plastiguage the new ones and if within spec reassemble with some assembly lube being sure not to touch the bearing surface with your bare fingers. If possible unwrap only one so if it is too small you can possibly return for bigger size. However if needing bigger bearings at that point you may want to have the crank machined.
 
#22 ·
Don't guess- measure.

Plasitgage is a diagnostic tool for in-car checks to determine how to proceed. It's not an engine assembly tool.

If you have excessive crank/bearing wear, you also have cam bearing wear, ring wear and rocker/shaft wear. You can cob it back together and stick inserts in it, but it's unlikely to solve your issue.

I would begin with a leakdown test to determine your cylinder sealing. Then I would look at those rocker shafts.. Not much you can do on the cam bearings without disassembly.

After all this, you have to keep in mind you have a vehicle with a reputation for head gasket issues.

I'm not sure why you can't touch a bearing with your fingers. That tin coating is so non-reactive, it was used for over a century to line metal food cans.
 
#23 ·
You guys brought up all good points . When installing the bearings I DO NOT oil the back of the bearing correct? I only oil the side that touches moving parts. Is assembly lube enough to start the car with? I have no idea how to prime an engine.

For right now I need this truck done and quick and out of the garage. If it works great if not it is getting donated. I am going to replace all the bearings and rebuild the pump. I know the rings are beat and have been fixing that by letting her drink oil. I only tore into this because I had an oil pressure problem. Honestly I am hoping I can get it all back together correctly.
 
#24 ·
You need to use some sort of engine assembly lube. You should be able to get the 2oz bottle of Clevite at any Advance, Zone or Oreillys. Coat the bearing surface liberally. It doesn't matter if the backs have lube or not.

Before you put bearings in, use the plastigage. Make sure you do it full width. If you can get +.001 inserts for it, that could help.

On this engine, the pump is attached to the crank, so there's no pre-lube to be done. You can pull the fuel injection fuse and crank it until the gauge bounces. But practically speaking, if you do a thorough job on assembly lube, you'll have better lubrication than it had when it had its last cold start.

Use a moly based assembly lube on the rod and main cap bolts- The ARP lube is pretty much the standard.

Advance stocks the Purolator L40316 filter- get one. Use that and I'd suggest Delvac 15w-40 oil. Or equivalent.
 
#28 ·
Ouch that is an ugly bearing!
I still assume that you are doing this as a bandaid for an engine in trouble? I think I mentioned earlier in this trread that the connecting rod bolts are torque to yield (one time use) are you planning on replacing them or just hoping for the best?
 
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