Oil light has nothing to do with the level. It has to do with oil pressure. Either the sensor is bad (does happen), the oil is to thin, or the oil pump itself is having issues. Last thing would be the cam bearings or lower end bearings. I'd never run 5/30w unless I was in Alaska. 15/40w works very well in these engines.

 

Isn’t 5 w just when it’s cold. When it’s warm it’s a 40 weight or whatever the 2 nd number is
oil pump on these 03 are a problem. I just did mine original with 130,000 km and it was in bad shape

 

that is my understanding of the numbers for oil. i have run 5w40 full synthetic in all my Rovers for many years.

 

Sort of.

5W30 means that oil is originally 5 Weight (when cold), but when hot still gives your engine the protection of a thicker 30 Weight oil, even though it isn't really 30 Weight (just 5... well less really since it thins when hot). Heavier Weight oil gives more protection when hot than does lighter oil (ordinarily).

5W40 means 5 Weight when cold, but protection equal to a 40 Weight oil when hot.

Of course, all oil "thins" when it gets hotter. Look at butter. That's oil, but it's really thick when cold. You can slice it! Heat up butter and it flows because it got "thinner."

So ordinarily a 10 Weight oil would soon flow like a 5 Weight once it gets hot enough.

Since thinner oil yields faster flow, the oil pressure gets reduced. Physics!

Anyway, the magic of hybrid oil tech can mean that even a thinner oil still gives your motor a lot of protection. Heck, you can buy a 20W50 oil which is really going to lubricate parts, prevent "shear" from metal on metal square angle intersections, etc even as your motor heats up. That's a 20 Weight oil (when your motor is cold) that still protects like a 50 Weight oil would protect even after that 20 Weight oil thins down due to heat.



As internal components wear, your motor naturally flows oil faster (which means less oil pressure which means less oil protection of metal on metal rubbing). Most people offset that lower oil pressure with thicker, heavier oil.

Eventually internal wear will still result in low oil pressure no matter the oil thickness, at which time you are looking at a rebuild. New bearings and oil pump and you are back in biz with a reset oil Weight clock again.

 

Best4x4's list hits a lot of the major possibilities.

One thing I would add is the o-ring on the oil pickup tube. When you drop the oil pan—hold that, when you do drop the oil pan, the crossmember might be frozen stuck; I had to have a welder cut the bolts off and put new ones on for me. Terrible job. Anyway, when you drop the oil pan, the oil pickup tube will be inside, bolted up into the block. You should remove it to get the oil pan off properly without bending the pickup tube. First off, clean the screen with degreaser and high pressure water. Second, and this is a big one, change the rubber o-ring with a new one! It's recommended you change that o-ring every time you drop the oil pan. One time my oil light was flickering at idle, and it was after I'd done some work on it. The o-ring was the culprit, I had neglected that cardinal rule and not replaced it. Of course there was also a little nick in the rubber, so it was obviously failed. I replaced it and oil pickup suction was back where it needed to be; no more oil light for over a year. Mechanic shops a lot of times don't change the o-ring, so if a mechanic worked underneath it that wasn't a regular Land Rover guy, he likely would have neglected this. Anyway, it's a relatively simple fix, the o-ring and possible clogged filter causing poor pickup. As RPMs get low when you stop and the oil is hot and thinned out, there's not enough suction to compensate and your pressure bottoms out.

If the oil pump's never been replaced, you've GOT to replace it. If it's not already fractured, it will be on its way very soon, and it could very likely be a cause of the low oil pressure at hot idle. It can still run while slightly fractured but it will get worse and eventually totally crap out your engine. Oil pump replacement is a must, and since you're getting the oil light, you should go ahead and get that job out of the way. While you're at it, you'll want to replace your timing chain and sprockets, since you're already in that far.

Conveniently enough, you have to drop the oil pan and pickup tube to take off the front cover, which is where the oil pump and timing chain and sprockets are housed, so you would knock out all of these possibilities at once. Even the oil pressure sender—it comes off when you remove the front cover to replace the oil pump, so it would be an easy time to replace the sender, just in case. They're only a few bucks.

Agree with several others, 5w30 is way too low. I had a mechanic do some work for me recently in the winter time, and he put in the "spec weight" oil without asking, dumping my fresh 15w40. Oil light started flickering on at hot idle. Called him up and found out he'd put the lighter oil in, because that's what the specs say. I laughed and said, "Yeah, it's gotta take thicker oil." I put my 15w40 back in and the oil light went away. THIS cause of a flickering oil light is likely due to worn bearings, because all of our engines are getting older. That's why most people run thicker oil than spec. We're basically compensating for worn out engine internals, but it works and it's a heck of a lot easier and cheaper than rebuilding your engine. You'll just have decreased MPG but hey, you bought a Land Rover, what's another couple MPG?

 

I don’t think oil grade makes your oil light come on
any 5w30 5w40 will not make your oil light come on.
You have other issues

 

If 5w30 oil makes the oil light come in then this guys rovers would be toast

 

i disagree.

 

5W30 is the same Weight as 5W40.

Mindblowing, right?!

But the first number is the actual Weight (when cold), whereas the second # is the Virtual Weight when hot (also known as the protection level equivalent).

So 5W40 gives more engine protection when hot than does 5W30, but they are both the same Weight when cold.

10W40 is twice as thick, when cold, as 5W40, but they give the same protection when hot.

Thicker oil gives you higher oil pressure, though.




And all oil gets thinner as it gets hotter.

 

Update: I’ve seen that the oil light has been on while in park or holding the brake as I’m pointing uphill in my driveway, but it turns off as I reverse and give it some gas, then it’ll turn on again after stopping and parking.

About the oil, I made a mistake: I’m using 10W40. I had some 5W sitting here that I’d used for power tools that I’ve got (Hilti and Bosch requirements).

I’m going to try to flush the system and use a heavier oil (15W30 or 40) and a new oil filter. I always check for leaks in the oil pan gasket and haven’t seen anything, but I can replace a few things just to be sure.

I watched the video about the oil pump; I’d really like to rebuild this motor when I’ve got another car and I can afford to have this one open for a bit while I’m figuring everything out. The engine has low compression in one cylinder and it ticks when it’s cold or idling (slipped sleeve, lifter or rocker maybe). I’d love to clean it all up and get it running smoothly again. Someday. I’ll see if I can get to the oil pump... anyone have an inexpensive part or know of an rebuild/exchange program? Is it common to need to replace the cover as well? I’m trying to keep costs down on this D2 as I’m investing a almost everything including my savings and my time in rebuilding my house now - first house I’ve bought, I’m 34.

Thanks again y’all - btw I really appreciated the information about the oil types. I learned a lot!