Even the normal M1 outperforms the Castrol GTX. However, GTX is absolutely the best dino oil available. I use Amsoil 5w-30. I used to use the Amsoil S2K 0w-30 as it's argueably the best oil available, but it just wasn't cost effective against their normal line of oils. VQ engines take quite some time to breakin. The longest OCI I've seen on a VQ is around the 17k mark and that was with Amsoil. I normally do 10k intervals. I am debating on doing Amsoil on the G as oil changes are free for the life of the car. While I love the added protection, it's more cost prohibitive since I get them for free.

 

+2

William
G35 S

 

I've heard that a couple times now and curious as to the source.

Here's what Mobile says in a faq on it's website:
http://www.mobiloil.com/USA-English/...AQs.aspx#FAQs4

I don't know that much about how synthetic is formulated, but it seems that either Mobile isn't telling the truth, the claims that Mobil 1 isn't synthetic are wrong, or there is a debate as to the meaning of "fully synthetic."

I've used Mobil 1 for years in my last 4 cars. I use synth partly because I'm the type who will forget about or put off oil changes because I get busy with work or something else. Running too long on synthetic is a lot better than running cooked dino oil. In my SUV, I changed the oil about every 7k mis and always felt I was playing it safe. I understand being cautious, but dumping synthetic after 4k miles strikes me as a waste. Might as well stick to dino and save $$.

 

I've never heard of Mobile-1. What is it? What does it do? I've always used MOBIL-1

 

I'm too lazy to look up the source, but what happened was Mobil-1 sued Castrol saying their Castrol Syntec product wasn't a true synthetic by Mobil's definition. There was something in it that made it not fully synthetic. Anyways, Mobil-1 lost the lawsuit and decided they were going to do the same because it's cheaper to make. Thus, they now sell the same basic oil as Castrol Syntec, the same oil they sued castrol over having. Mobil did come out with the extended performance which they charge extra for.

Your main choices for true synthetics are:
Royal Purple
Castrol Syntec Euro Formula
Mobil-1 Extended Performance
Amsoil

I'm sure there are more, but just google the castrol mobil lawsuit and you can find your own info.

 

You are correct, Mobil 1 is a Group III based synthetic oil. Stay as far away from Royal Purple as possible. It's just plane horrible for passenger car use and UOA's show you can't use it for much more than 3k oil change intervals in a VQ engine. Castrol GTX performs better than Royal Purple.

 

Did you base the extended dino usage up to 10K miles, before switching to synthetic, for proper oil ring seating reason? Has there been any actual tests on the VQ35 about this?

I'll probably stay with Mobil 1 10w30 (warmer SoCal) with 4-5K mile intervals, after break-in period, as I've been happy with perf results on my '00 Maxima SE 5MT (90K now), still going strong even with a few track days thrown in

 

I use Pennzoil 5w30 and a Bosch 3300 filter. Not sure how good the Bosch is but it's priced a couple bucks higher than the Fram and looking at the packaging data (if you believe it, lol) it appears to be a more effective filter.

As far as having to remove all 17 bolts for the plastic engine underguard, my 07 Journey has a hinge on the plastic cover that allows complete access to the oil pan and filter by just removing the back four bolts. You have to use something to keep the plastic "hinged", I just used an extra jackstand to keep it pryed open while the oil drained. Much easier than having to unscrew 17 bolts