Royal purple XPR 10w40 question

[jmatta]

As JFP stated regarding the debate, oil issues have been beaten to death on this and other forums. I've used RP for years in my cars (mostly 911s), but for one reason or another, have switched to Castrol Syntec 10W40 for the last couple.

I will not use Mobil 1 or any other 0W40 product in my Box S...too thin.

You can usually find Castrol Syntec for under $5 on sale at AutoZone or comparable.

[eightsandaces]

I found the last ten quarts of Mobil 1 10 - 40 W high mileage formula, my car only has 30K but it was the best synthetic I could find in that range anywhere in the entire city. I figured the "high mileage" formula wouldn't hurt anything, hope that is right..

[JFP in PA]

Originally Posted by eightsandaces

I found the last ten quarts of Mobil 1 10 - 40 W high mileage formula, my car only has 30K but it was the best synthetic I could find in that range anywhere in the entire city. I figured the "high mileage" formula wouldn't hurt anything, hope that is right..

Mobil 1 10W-40 is a much better product than their 0W-40, but you can still a lot better yet for less money.................

[eightsandaces]

Originally Posted by JFP in PA

Mobil 1 10W-40 is a much better product than their 0W-40, but




you can still a lot better yet for less money.................

Maybe with free shipping, the selection here was so weak I did look online! So apparently, until later in Spring, I can't do any better for the money.

[JFP in PA]

Originally Posted by eightsandaces

Maybe with free shipping, the selection here was so weak I did look online! So apparently, until later in Spring, I can't do any better for the money.

Go to your local Wal Mart, buy the 5 quart containers of Castrol Syntec 10W-40, a better oil and sells for about $23 per 5qt container, and no shipping............

[tonycarreon]

didn't use the XPR, but i did use RP.

can't say i found any reason to think it was worth the extra $$

[j.fro]

Ditto on tonycarreon's experience. I've got the Castrol in my car now.

[Gilles]

Originally Posted by JFP in PA

Go to your local Wal Mart, buy the 5 quart containers of Castrol Syntec 10W-40, a better oil and sells for about $23 per 5qt container, and no shipping............

JFP; +1 on Syntec

I switched from the Mobil1 to the 10W-40 Syntec after reading good comments here.

Like it better than the M1 and I do feel a difference mostly upon start up, it seems to run smoother. This comparison was after finally installing the Pedro's sport engine mount (nice..!) and the reduced vibration with the Syntec was noticeable.

PS, However I paid $25 at Walmart for the 5qt jug...

[Daniel R]

I would really like to understand the difference between oil weights, benefits and drawbacks.

I understand the whole viscosity thing, and what the two numbers in the multigrade oils mean, however it seems there are as many men as opinions in this debate. I have heard people say that thinner oil is better as it squeezes into gaps more easily, especially upon start-up, and hence is a better lubricant. I have also heard the reverse. I have heard people switching to lighter weight oil as the car ages, and others the reverse. What is the absolute truth, if there is such a thing?

I remember switching from Mobil 5w-50 to Mobil 0w-40 and immediately noticing the engine seemed to rev more freely and cleanly, whilst at the same time my coolant temp was running slightly warmer. To a rank amateur such as myself, this is a confusing result. One would assume the engine feels more free which would imply LESS friction, but why the HIGHER temp which implies MORE friction?

If anyone could shed some light it would be great. I know there are many articles out there, unfortunately most of them written by hacks who are not mechanics or engineers, and are probably based on nothing more than speculation.

All info welcome, just please no oil wars!

Daniel