View Full Version : 5w30 or 10w40?

06-06-2007, 07:45 AM
Hi guys,

I read a lot of posts about what oil to use, and it seems that the best oil weight is 5w40. But I tried all different auto shops but no one really carried it. All they have are 5w30 or 10w40. I'm wondering which one is better, and if you know which shop might carry 5w40?

I live in Northern California and go to Tahoe Lake for skiing occasionally. I'm now using Royal Purple 5w30 as they don't carry 5w40 either.

Thanks for your input.

06-06-2007, 08:23 AM
I would only use 2 oils

Redline - 5w40
carried by Monument Auto Parts in Pacheco Sadly this is the only place i know of that carries it. The Redline factory is located in Benicia i believe.)

Mobile 1 - 0w40
I get this at Kragen, but i've seen it at Pep Boys, Auto Zone, and Monument Auto Parts.

06-06-2007, 08:32 AM
OFF TOPIC: ActiveMonkey, what the hell is in your avatar? I've never been able to figure it out!

06-06-2007, 08:32 AM
i use 5w 30

06-06-2007, 08:55 AM
OFF TOPIC: ActiveMonkey, what the hell is in your avatar? I've never been able to figure it out!

Glowing Ko3 Turbo, i took a 2 hour long HARD drive through the hills. the turbo was a bit hot to say the least. [:D]



i use 5w 30

Ok, but what brand, and where in the SF Bay Area can you find it?

06-06-2007, 09:04 AM
I think 5w30 can be found in any auto shop.

I don't know if I should use Mobil 1 anymore. As some of you might know, they have changed from full synthetic to grade 3. And according to a 350Z forum, some members did oil analysis after using Mobil 1 and found more leads contained in the oil than other oils used. Mobil 1 USED TO BE good oil. Will it be any problem if I keep using the Royal Purple 5w30 oil? How much different is it from 5w40?

06-06-2007, 09:11 AM
If they switched then would their bottle still say "Full Synthetic" or would they have to change it?

06-06-2007, 10:30 AM
Here is the quote:

"Mobil sued Castrol for calling their oil a full synthetic. Which according to Mobil it wasnt a full synthetic like M1 since its not made from a Group IV base stock.

They lost the case, so they decided to start using the cheaper base stock just like Castrol,pennzoil etc. Why make a real synthetic that costs you more money to make then the competition who is charging the same price for their fake synthetic?"

And here is the link:


06-06-2007, 10:46 AM
omg. I just used Mobile 1 0w40 about a month ago. Dammit. I'll switch back to Redline at the next change.

06-06-2007, 10:52 AM
I've heard from several shops in my area that 10W is too heavy for Audis...and to use 5W (or 0W). He also pointed out that during the summer it won't be a big deal to use 10W if you have or want to.

06-06-2007, 10:59 AM
I don't know, but they said the Mobil 1 is bad for the 350Z engine (contains more lead count), so I changed it to Royal purple for my Z. I think I will stick with Royal Purple 5W30 for my 1.8T B5 too.

06-06-2007, 11:33 AM
actually I'm more concerned about the operating temperature weight ( the 30 in 5w30 for this case). Not sure how much of a difference between 30 & 40