OK, I've heard a lot of differing opinions on what oil to run when and where. I live in Colorado (4 seasons, sometimes cold but mostly mild)
What is the best oil option for a D2 in this environment and why?
I have heard 10w40, 15w40, synthetic, non synthetic...

 

which oil is best? The kind you change every 3k miles.

I use Valvoline high mileage 10w-40 during the winter (not much winter in San Antonio) and 15w-40 rotella during our hot a$$ summer, spring and fall months.

 

Why? Those have the same hot viscosity.

 

I really don't think it is necessary to resort to insults. I also understand oil viscosity ratings. So sorry to impinge on your valuable time, though.

My point is that you could use the 10w-40 in summer too, as the only difference is the cold viscosity, and in summer the hot viscosity is the main issue.

 

Because Rotella is better in Discos and Shell doesn't make a 10w Rotella.

It's the ZDDP additives, not just whats before the W, though that is important too.

This is all well documented on this site which is what I think Jared was getting at....

https://landroverforums.com/forum/di...estions-46975/

 

I run semi-synthetic 10W-40 all the year around. Temperatures here very rarely drop below 0C and are usually 5-10C during the winter months and circa 30C summer but have reached 40C occasionally. I always run good quality oils (but we are talking a diesel engine TD5 oil not gas) like Total or Elf which meet the recommended standards. Oil changes run to 10,000 miles but often far less maybe 5K miles (the recommended is 12,000 miles)

 

Viscosities at 100° C

15.7 Chevron Delo 15w40

15.7 Rotella 15w40

15.2 M1 10w-40

14.6 Mobil Delvac 1 5w-40

14.2 T6 5w-40

14.2 Chevron Delo 5w40

14.1 Amsoil AMO 10w40

13.4 M1 0w40

12.0 M1 10w30

These are from VOA on BITOG. So, it turns out all 40 weight oils don't have the same viscosity. I recently learned this and was pretty surprised.

As the "Stupid Oil Question" thread will attest, oil threads always turn into gigantic arguments. Several of us question the main ideas in that thread. The best thing you can do is go to BITOG and do some research over there.

The two caveats about our trucks are:

1) These are extremely dirty engines, so extended oil change intervals are not a good idea.

2) We have flat tappet camhafts that need an additive called ZDDP that is typically found in diesel oils.

Otherwise, it's up to you. My truck ran much rougher and noisier with 15w-40 Rotella, so I switched to M1 5w-40 TDT which smoothed it right out. I've also tried Rotella T6 which ran much smoother than the Rotella T. After the last couple of years of experimenting, I'm pretty much done with dino oil. Every vehicle I own runs noticeably worse with it. This post has my thoughts on synth vs. dino. Another of my posts about oil.

 

I've been running Rotella T6 5W-40 year round with no issues but I'm surprised to see the viscosity is lower than other 40 weights. My oil pressure is 20 psi at idle and 40 psi at 2,000 rpm when hot so that works for me.

 

"which oil is best? The kind you change every 3k miles."
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Yes, I fully agree. Way too many guys waste way too much money on this or that special oil, especially on synthetic oil. I used to be one of those guys, before I watched several close friends, who spent a great deal of time on the road, part of their job. I saw their engines repeatedly torn down over time, inspected carefully for build up of varnish, tar, carbon deposits, other deposits, etc. with some using only this or that brand of oil, or only synthetic oil, etc., compared to others who "used whatever oil happened to be on sale when they changed the oil," which they all did every 3,000 miles. Results: No perceptible difference in internal engine wear or build up of deposits, no matter what oil they used. So, when oil is changed often enough, the brand of oil, synthetic or non synthetic means little or no difference. For warmer weather, use heavier viscosity; for colder weather, use thinner viscosity, that is important to lubricate better while engine is cold or hot, and Rover engines, due to oil pump type characteristics, function better with thicker viscosity oil, so take that into consideration.

 

I remember talking to an old boy with a very old Austin Somerset (don't mention Somerset at the moment - floods) I asked him what he used and how often did he change the oil - his answer was...........whatever is available, he said he changed it once so I checked the odometer, there was 180K miles on the clock, he'd had it from new, for 40 years . He just topped up the oil when he remembered to do it. He's never changed the gearbox or axle oils. Bearing in mind there were no synthetic oils in those days and Castrol was the norm. If it was ever revved over 3-4K revs I'd have been surprised. Makes you wonder whether we are all being taken for mugs by the oil companies.

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In a word, we would call this a 'rust bucket'.