Hello everyone, I have a 2000 Landrover Discovery II which is just coming out of a head gasket change. It is a 4.0L V8 which was previously using 10W-30 oil. Would it be ok to use 5W-30 instead? Any positives or negatives of using it? Thanks

 

ok....yes
ideal.....probably not


common consensus is rotellat 15 40w or the t6 for colder climates

 

What Dusty said...

You have a flat tappet cam, which needs ZDDP to keep it luburicated. Thinner oil may be better for fuel economy (marginal), but does not keep up the oil pressure, very important in getting the oil up to the top end. Rotella 15W-40 is excellent in soot and gunk removal, maintaining a clean valvetrain and lube passages. Others that are excellent are Kendall GT-1, Mobil 1 15W-50, Valvoline Racing, etc.

Rotella is readily available at most auto part stores and under $13/gallon at your local Wally World.

 

Also, 10w-30 is not recommended in normal US summertime ambient temps.

I run Mobil 1 5w-40 and much prefer it to Rotella 15w-40, but any 40 weight diesel truck oil (because they have the ZDDP described above) is better for this engine's longevity than a 30.

 

I live in Ontario so it gets fairly cool but in the summer it can get fairly warm. That's why I was considering the 15W-30 beacuse some recommend it and some disagree.

 

There have been many threads about oil here, and they often turn into arguments.

The science is that the first number is the oil's thickness when cold, and the later number is the oil's thickness when warm. Most engine wear occurs when the engine is cold because the oil isn't flowing properly. 15w oil will increase that cold-oil wear because it flows worse than 5w oil when cold. This cold engine wear is exacerbated by very cold ambient temps.

Because you live in the frozen north, you should certainly run 5w-40, either Rotella T6 or Mobil 1 Turbo Diesel Truck oil. Both have the additives the engine needs for valve train longevity (ZDDP), and both will lubricate better then 15w-40 when very cold. Both also have detergents built into them to keep the engine as clean as possible. Finally, both are also synthetic, so they will cost a bit more, but also offer the benefits of being synthetic oils.

Next discussion: which filter to run. There's a thread here that recommends running a giant Wix filter, but if you dig in 10 pages you find a Wix engineer saying it's a bad idea to run that filter because the bypass valve pressure is too high for the engine, and it could starve the engine of oil. So, IMO you should just run the stock filter recommended by your local parts shop.

EDIT: I just looked at the manual, and 30w oil is good up to 95F/35C. So it might be ok to use up north. That said, I'd still stick with the oils I recommended above because of the ZDDP and detergents that will keep your engine in better shape, and because I personally think these trucks benefit from a slightly thicker oil. I ran 10w-30 for a winter and it seemed a bit too thin; the valve train got noisier.

 

Just wanted to say thanks for the great info on this forum about oils. I just changed my D2's oil to the Rotella 15w40 with a Mahle oil filter (purchased at roverparts.com) and the tapping which had gotten so embarrassingly loud even with a full load of regular old 5w30 or 10w30 has now ceased. Now I can hear some other things to address, like a squeaky bearing in there somewhere.

Thanks again!

 

Ok thanks a lot everyone. Also I meant 5W-30 not 15W-30 that was a typo. I'm going to try the 5W instead of the 10 and see how it works.

 

Xw40 will make your truck run smoother and quieter but why bother asking if your going to just do what you wish no matter what advice you may get.

 

Always great to see others opinions. I wasent totally sure what to use that is why I had asked. I'll look into the Xw-40. Sounds like a better oil. Don't need ticking sounds to come again by using the 15w-30 or 10 Just replaced the lifters and many other parts in hope to
fix the tick and run a little smoother. Thanks again for the feedback appreciate the help