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You left out the best part of buying oil and filters at FCPEuro. If you send back the old oil and filter to them they credit you for the full purchase price on your next order. I know it does sound unbelievable. I was skeptical as well. I just did my second oil change and they credited me the entire purchase price on my next one. Details are in the thread below.
So fwiw, I made a spreadsheet with a bunch of oil specs that I could find. One thing I learned is that an oil viscosity grade has a range of acceptable viscosity. (caveat: the JLR certification row isn't entirely accurate - I was marking an oil as meeting it if it met any of the JLR certs, not the specific one for the F-Type. I've also found that a lot of information is just missing from a company's data sheets.)
For example, if you look at the API spec, 20W oil tops out at 9.3 @ 100C, while that's where 30W starts.
So if you look at my chart, Red Line 0w-20 is a 9 @ 100C (a thick 20 weight), while Liqui-moly 0w-30 is a 9.5 @ 100C (a very thin 30 weight). For tl;dr reference, the JLR Castrol stuff is an 8.1 @ 100C.
When I finally spent time looking into all this stuff about oil, I was a little amazed by how much deeper it can be than just the 0w-20 or 0w-30 etc. Now, there may be special additive package in the JLR oil, but I've read that you can't claim certain licensed certifications if your additives are out of spec with what the cert requires, so... Myself, I'm going to be running the Valvoline Restore & Protect for a few changes before maybe switching to Red Line.
Anyway - use your own judgment - but hopefully this information helps some of you.
0W-20
0W-30
The colour coding: To explain quickly, it's arbitrary. I coded some numbers where I understand what the ranges mean, from green (relative best IMO) to red (relative worst for this application IMO). Don't take the colours as gospel of anything since you're not in my brain, haha.
Last edited by Nick R; Yesterday at 01:30 PM.
Reason: Color coding explainer
This is sanctioned by the company, basically giving you free oil?!
Yes it actually is. Free oil and free everything else. There are of course rules. See the link below. I am thinking they had actuaries run the numbers and figured out they would not lose money on it.
Yeah the difference between 0w20 vs 5w20 is probably negligible given the same oil. Both are 20 weight at the end of the day, the additives can maybe impact shear degradation slightly but with the factory spec synthetic oil we should be using and the proper change intervals, I don't think it matters too much even if you are tracking the car.
When talking about higher base weight oil, I would be concerned about oil pressures and clearances. My AJ133 is not an old Chevy 350, it might have bearing clearances made for thinner oils. Also things like cam phasers may be impacted. I say "may" because I honestly don't know how these motors react to heavier weight oil (I imagine RoverJoe may) but I default to "the engineers know better" vs "it is a fuel economy conspiracy that sacrifices motors longevity".
I won't be putting 40w (or even 30) in my motor anytime soon. I would rather stay with the specified oil, change it frequently, and periodically run Blackstone tests.
In my personal cars, using my 350z as an example, I was playing with oil weights to see if the factory noisy valvetrain could be damped. I had owned the car from new, it was low mileage, and had run the 5-30 ester oil at the start. I tried everything up to a 15-50, which did help, but noticed with the heavy oil when it was cold, there was a 'hunting' of the VVT system as the oil pressure was so high and the oil so thick, the PCM was chasing itself trying to get the cams where it wanted. This was a 2008 car so the systems were not as sophisticated as we have now but not far off from the AJ line of engines. It was interesting to note how the pressures reacted to the temperatures and oil weights (car had an oil pressure gauge stock), but in the end I stayed with a 10-30ish oil most of the time. Not worth risking valvetrain damage just to get the tappets a little quieter.
In my personal cars, using my 350z as an example, I was playing with oil weights to see if the factory noisy valvetrain could be damped. I had owned the car from new, it was low mileage, and had run the 5-30 ester oil at the start. I tried everything up to a 15-50, which did help, but noticed with the heavy oil when it was cold, there was a 'hunting' of the VVT system as the oil pressure was so high and the oil so thick, the PCM was chasing itself trying to get the cams where it wanted. This was a 2008 car so the systems were not as sophisticated as we have now but not far off from the AJ line of engines. It was interesting to note how the pressures reacted to the temperatures and oil weights (car had an oil pressure gauge stock), but in the end I stayed with a 10-30ish oil most of the time. Not worth risking valvetrain damage just to get the tappets a little quieter.
What do the main bearing clearances look like on these motors? A risk with something like 40w or mostly ok?
The hydraulic pressure issue makes sense to me - I have also read about some pumps designed for thinner oil struggling to move the heavier stuff, and I wonder if significantly heavier oil could trigger a filter bypass.
In my opinion, the best value at the moment for oil that fully meets the JLR spec is Castrol Edge Extended Performance in 0W-20. In the US, you can get this for $27.82 per gallon, after tax and delivered, from Walmart. I'm currently using this in both of my vehicles (Defender 110 and F-Type). That said, as others mentioned if you are changing the oil every 5K-8K miles or so any modern mainstream full synthetic is going to be fine. These super-premium oils only matter if you really push the interval out >10K miles.
All this scientific crap means nothing just change it at 3-5000 miles
with the recommended oil, no disrespect, timing chains loves clean oil
and top tier fuel
