2K2 LS1

iTrader: (2)

Mobil 1 synthetic 10w-30 <img src="gr_images/icons/cool.gif" border="0">

Trevor @ Texas Speed & Perf.

iTrader: (3)

[quote]Originally posted by Fireball:
<strong>Though 5W30 and 10W30 have the same base, the additives that allow the cold start viscosity will thin out the base. Thus 5W30 is significantly thinner that 10W30 at operating temps.</strong><hr></blockquote>

Thanks for the response. <img src="gr_stretch.gif" border="0"> FWIW, my 346 had right at 26,000 miles on it when it came out for the 383 in my T/A. I had run Mobil 1 10w-30 and 5w-30 since the car had 2,500 miles on it, and the bearings looked AWFUL. All of them were already deep into the babbit material, and we were amazed at how it hadn't spun a bearing. I'm not saying that the oil caused the spun bearing, but there are a LOT of cases of it.

AndUAndI

Redline 5W-30, but it sounds like my next load will be 10W-30.

2002SS

Mobil 1 5W-30 Here.

Bugblndr

I used to run Mobil 1 5W-30 for the first year I had the car. Now I only run 10W30 Dino oil, usually Castrol.

Damian

iTrader: (89)

Thanks for the back up Fireball! <img src="gr_images/icons/cool.gif" border="0">

Fireball

iTrader: (21)

this topic comes up 2x a year or so...I like to make sure people realize that what the owner's manual says isn't necessarily the best thing.

haha..if you read it it says to drive easy and all that too <img src="gr_images/icons/wink.gif" border="0">

CHRISPY

I am running 5W30 Castrol syntech in the winter and 10W 30 Castrol Syntech in the summer.
My oil consumption dropped when I went to Castrol over Mobil 1 synthetic.
Cheers,
Chris
I think 5W 50 Castrol Syntech might be interesting as well.

[ March 04, 2002: Message edited by: Chris ARE 360 ]</p>

Ian

4.6 DOHC Cobra guy butting in here.. It's recommended that our cars run 5w 30 oil (I use mobil one trisynthetic) and we (at least I do) regularly spin our motors to 7000 rpms.. almost 63k on the car now, and no problems ever. Sure the 5w30 is the problem??

Hopefull I'll be in a soon!

01Z0H6

iTrader: (63)

Mobil 1 5/30 Synthetic with Mobil 1 Filter.

antsam17

Used Pennzoil 10W-30 Synthetic burned 2 qts every 3K.

Used Mobil 1 10W-30 and 5W-30 Synthetic burned 2 qts every 3K.

Just put Royal Purple 5W-30 in 100 miles ago and the new PCV fitting and we'll see. <img src="images/icons/rolleyes.gif" border="0">

TTopJohn

The last time there was a big long thread to try and chronicle all the spun main bearings, just about everyone who had it happen reported that they were LOW on oil - that was the issue, not oil weight.

And I must disagree with the statement (paraphrased here)"when your spinning to 6000 you better have heavier oil or your main bearings are in danger"
High load at low rpm is what can kill the main bearings, high load at high rpm is not a problem for them.

StevieZ

iTrader: (3)

Royal Purple #41 (Racing application oil equal to a 10W40 but has no SAE rating) It's better oil than the regular SAE grades with a higher additive package.