Does anybody have experience with faulty oil pressure relief valves? do these fail often? I recently installed new gears in my oil pump and I'm still getting low oil pressure. I was contemplating popping out the oil pressure relief valve to see if that could be causing an issue.

 

#1, What weight oil are you using? Heavier oil gives you higher oil pressure.

#2, How many miles are on the engine?

As your connecting rod bearings wear down, oil flow increases due to the larger clearances, and that increased flow decreases your oil pressure (at least that's true in a closed system like a motor...the opposite may seem true for an open system like a fire hose spraying at you).

New rod bearing sets are about $38 on eBay. You can drop your oil pan to reach up to replace your rod bearings with your motor still in your Disco.

If switching to a heavier oil seems to solve your oil pressure issue, then you've bought some time before needing new rod bearings.

 

1.) I'm running rotella t6 5w40

2.) there's about 160k miles on it. If I end up doing the rod bearings should I go ahead and do the mains too?
is there any possibility it's a walked cam bearing?

 

#1: 5W40 is too light. You could install new oil pump, pressure valve, rod bearings, et al and still potentially have low pressure with 5W40!

Owner's manual calls for 10W40, I use 15W40, and many Land Rover independent mechanics are now recommending 20W50.

#2: 160k is a lot of miles. That's great life for rod bearings. Time to retire them nears...

#3: replacing the mains with the motor in the LR is doable, but a pain...a significantly larger job than just replacing the rod bearings...plus, unless your motor sounds clackity-clack like a diesel at idle, there's little need or perhaps even no need.

#4: sure, you could have a cam bearing that walked or you could have a clogged or detached oil pickup tube. You could see both of these conditions once you drop the oil pan and look up into the internals of the lower half of your motor.

Certainly you will want to clean your oil pickup tube of any RTV or other debris that may have accumulated in or around it plus tighten its connections if any are loose or worse (it is just held on by 3 bolts and is right in front of your face when you drop your oil pan).

That's free bonus extra oil pressure right there if it has become loose and is dropped down off of its sump connection.

 

Thanks for all the help!! I'm going to order main and rod bearings. During hot idle I get a light ticking, nothing crazy though. Does the install require me to completely remove the crank? Also worst case scenario if a cam bearing did walk itself out is it possible to replace that with the engine still in the vehicle?

 

Does the tick speed up when increasing engine RPM?


No, you don't have to remove the crank. Some people can make a special tool to push back in cam-bearings that have walked, while others may remove the top half of the motor plus remove the cam itself if you want to replace cam bearings.

I would think that's a bit extreme, though. An upper-engine tick can often be solved with Seafoam, or if not with Seafoam cleaning by inspecting/replacing rockers...not new cam bearings.

You can visually see if a cam bearing has walked, though...when you pull off your oil pan. Just look up! If it hasn't walked, then why tear apart the top half of the motor?!

So...


I would suggest pulling the oil drain pan. Order your oil pan gasket and your rod bearings (cheap!), first.

Clean your oil pickup tube after dropping your oil pan, then use a 10mm (spline?) socket to remove the 2 bolts that hold each rod bearing cap. Install new rod bearings. Reinstall the cap. Repeat 7 more times. Bolt the oil pickup tube back on, then reinstall the new drain pan gasket and oil pan. Fill with 15W40. Start the motor. Idle until warm. Then if there is no tick do a slow drive, then a medium speed drive, then a full speed drive listening for your tick.

If the tick is gone then you probably don't need to do new main bearings and new cam bearings!