Hey everybody, im at my wits end with oil pressure. I recently did a head job on my 03 discovery and everything went pretty well. Got it back together and still getting oil light when rpms drop to around 1200. When hot idle im only getting 7 to 8 psi. Took it straight home parked it and the next day came out and started it up and oil light was on instantly and my gauge was reading LOW. Brand new oil pump gears (old ones were fine, no cracks) but no change. This was happening before I pulled it apart as well, oil light coming on below 1200rpm when hot. Im thinking its worn cams/bearings but thats just my guess. Let me know what you guys think and if theres any info i might have left out.
Thanks!

 

worn main bearings, and also worn rockers. Change oil filter (perhaps a bad one), use the Purolator one mentioned in the tech area sticky about oil questions. Use 10W40 or 20W50 oil, not 10w30, 5W20, etc. 15W40 Rotella is good.

What PSI do you get hot at 2500 rpm?

 

How do you tell if its a bad oil filter? I have a new mobile 1 long on there right now. I only use the rotella since I have owned it. Do you think the cams are good then. Shouldn't i replace the cams when you replace the rockers, or is that lifters? Im stressed out and my mind is shot right now..

 

Oil filter is a simple swap. If new one cures it, throw old one away. I suspect it will not, but it is the cheapest fix. It is the lifters you replace with cam. Easier to get at worn rocker arm parts - Lower end bearings can also be done wih motor in the truck, write up in tech area.

Light coming on is a serious issue. Have you done a mechanical gauge PSI test? Without it you could be running 18 PSI at 2500 rpm and the light will be off and every bearing surface will be wearing faster that politicians can spend tax money.

 

Who's filter are you using?
Once the filter is ruled out then you better look at the crank bearings next.

 

Yes, I installed an aftermarket guage and was getting around 30psi while driving at around 2500rpm. I thought that was low along with it dropping to 7psi at hot idle so I parked it. That's when I went out to get some cold idle readings and all it said was low and the factory oil light was on instantly. I will grab another filter and see if that's it and ill start researching the bearings.

 

the oil pump gears factory or aftermarket?, the reason I ask is the factory gears have a in and outside to them, the aftermarket ones do not.

 

Perhaps a trip into the oil pan may reveal blocked pickup screen, or that pesky O-ring or gasket for the pickup tube (sucking air, not oil).

Also, if it is the mains showing copper the crank should be examined, some have cleaned up with emery cloth, a worn crank will quickly eat away new bearings.

With wear on the mains, you would expect wear on the top end parts as well.

Pix of a pick up screen gunked (non Rover), mains showing copper, crank needing attention, pickup tube port in top left, rocker. The tube the rocker rides on can also have enough wear to drop oil PSI.

Considering the D2 spec is 50 PSI hot, that 30 PSI figure is not good news. 20W50 and 10W60 oils come to mind, needs to be warm weather.

 

I'm using the tall mobile 1 filter. I will pull the pan and check the crank for wear. Even if the filter is bad, I'm still getting low pressure at hot idle so something needs to be done.
I've never heard of an inside and outside to the oil pump gears. I have the original pump gears so I will compare them.

 

Good filter, so it is time to pull the oil pan.