My first oil change was at 1000 miles ( break in with 5w-30 bulk Dina oil).

My next change was at 2500 miles figuring to get rid of the last break -in residuals that may be in the crank case.Also I was getting increeasingly nervous about running my engine on 5w-30 dino juice as much as I like to rev it.

What to refill was the question?

Well, I felt my 2 perennial favorites of oil for NA engines, Mobil1 0w-40 and german castrol 0w30 (runs thick at operating tempos for a 30 weight),Might be tooo thick at operatings temps for this real new and tight engine.

usually I like thicker oils for the HT/HS, but I went with Mobil1 10w-30 which is about nine and a half centistokes at 100 degree C, if memory serves.

Also M1 is VII's free in the 10w-30,but not in the 0w-30 or 5w-30 versions.Even tho winter is coming up , living in kentucky the 10w-30 will be plenty start-up capable and the 5w and 0w- will be unneccessary.

So now I am enjoying VII free, Mobil 1 10w-30, Yayy!..

As hard as this car was driven lately, I felt a change was neccessary, also it gives me piece of mind to have a group IV oil in my brand new VQ35.

I know your not supposed to switch to syn early says conventional wisdom, which is usually a good starting point.For this reason I didnt put in syn on my first change.

But many other highly modern engines have M1 as factory fill.So how harmful can an early syn switch be?

Amnyway i did it and feel good about it.

Fred..

I'm sure all will be well. How you likin it so far?

Loving it.Its Awesome!My best car purchase ever?

Fred..

on a side note, do you think 5w-30 mobil 1 is ok for the cougar in the winter? If not, what would you recommend. I woudl liek to keep it on synthetic, but if there is something you think would be better, I'm willing to try. The 240 is in storage until i can finish the de swap and turbo.

It might be a bit over kill for a looser motor ( V8 Cougar?)

Also for higehr mile engines I thinka good bet for you is 5w-40 SynPower , really like its aditive package too almost a drive-clean type oil.

Fred..

cougar is a 2.5L v6 with 32.5k on it. what do you recommend?

Altiman94 wrote:cougar is a 2.5L v6 with 32.5k on it. what do you recommend?

Chevron Supreme 10w-30, Valvoline Durablend 10w-30, Pennzoil 10w-30

Fred..

sounds good. thanx fred

Fred,

Good call. Might I also suggest changing diff and tranny fluids after 3k miles? I should have done it that early on my G. Mileage went up by about 2mpg.

MOTOP wrote:Fred,

Good call. Might I also suggest changing diff and tranny fluids after 3k miles? I should have done it that early on my G. Mileage went up by about 2mpg.

I did that but not until 11,000 miles.. , still much earlier than recommended.

My Tranny shifted so much better afterwards (see other posts here in this forum)

Fred..