Mobil 1 0-30 or 0-40

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Feb 8, 2003
New Hampshire
Should I switch from Mobil 1 0-30 to Mobil 1 0-40?

Vehicle is 00 Silverado 5.3 w/54200 miles.

There is some noise at start up, but I don't think its this infamous cold start knock. So far 5k interval it has used about 1/4 quart. The most the engine has used is 3/4 of a quart and that was with the 0-30 this time last year. Normally its about a 1/2 quart with Mobil 1 10-30.

I am running the 0-40 in our 99 Saturn 1.9l with 45k and it seems to be slowing the comsumption compared to either the 5-30 or 10-30 Mobil 1.

I was thinking of switching to the 0-40 but many on this site do not like it due to is shearing. However far more dislike the 0-30 for the same reason.
The GC 0-30 is the same price at Auto Zone as the Mobil 1 0-40. Delvac 1 is not as readily available. This is my dilemma!!!
I would not use Mobil 1 SuperSyn 0W-30. Mobil 1 SuperSyn 0W-40 is a much better choice in my opinion than M1 0W-30. Even better still would be the German Castrol Syntec 0W-30. The GC 0W-30 and M1 0W-40 are both ACEA A3/B3/B4 oils and are both a great choice.

Mobil 1 SuperSyn 10W-30 has very few viscosity index improvers and may leave your motor cleaner than the other grades of Mobil 1. Mobil 1 5W-30 and 10W-30 are both rated ACEA A5/B5. Perhaps M1 10W-30 in the Summer and 5W-30 the rest of the year may be a better choice than M1 0W-40.

I have been to four AutoZones here in Las Vegas and I have never seen the German Syntec 0W-30. 0W-30 is really hard to sell in a warm climate like we have here in Southern Nevada.

[ January 06, 2004, 02:14 AM: Message edited by: Sin City ]
I have a 2003 Silverado with the 5.3 and I use Mobil 1 10w30 year round. My engine is smooth and quiet on M1 and burns 0 qts so far with 14,000 miles on her. It was -9f today and it started like it was a warm day with no start up noise or cranking slow down. I like this M1 10w30, it flows better then most if not all dino 5w30's in cold weather and is much more stable. Give it a try and see what happends.
Lots of opionions.
I found that GC causes more cold noise than Mobil1.
IMO, any thicker oil would be quieter than a thinner oil when hot. I wonder how much of this noise is psychological.

Trial and error. Try them all and draw your own conclusion. I'd stick with the thinner 30wts up north during the winter.

I see nothing wrong with the 0w or 5w --30wt synthetics regardless of brand.
Thanks to everyone that replied I bought some GC 0-30 and am going to give a try. I will keep the Mobil 1 0-40 for the Saturn.

Thanks Guys...
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