Mobil 1

Pancho · May 12, 2004

Has anyone considered using Mobil 1 Racing 0W-30 or Mobil 1 5W-40 Truck & SUV versions of Mobil 1 synthetic motor oil in their 8.1? I did not know they had a special oil for heavy duty trucks until today when I ran across it ordering filters.

GMCTech · May 12, 2004

As you know, your big block will burn some oil. As you also know, synthetic is a thinner base oil, thus you will burn more oil.

I think Mobil 1 is fine, and we have a few customers that use it in their 8.1s, but we always sell them an extra quart to add to their truck between changes.

You will probably burn about 1 quart every 3000-4000 miles. Regular oil about half that.

Hope this helps.

Chevyfreek · May 12, 2004

The heavier weight synthetics probably won't burn of as quickly in the 8.1's. The 5W-40 Mobil 1 would probably be your best bet. I run Amsoil 10W-40 in my 6.0L and it has worked really well. I go through a half a quart or so every 3500 - 4000mi or so. Vaporiaztion happens with any oil though. I like the Amsoil because I can run it for 25,000 miles and just have to change the filter and add oil at 12,500 miles. This is using an Amsoil Superduty Oil Filter....

Pancho · May 12, 2004

I am right at 60,000 miles and have been running Mobil 1 5W-30 SuperSyn but for the first 4,000 miles. From the Mobil description of their Racing and Truck & SUV versions it looks like it might be a better quality oil than the SuperSyn. It is certainly priced that way. Just wondering if anyone out there is using it?

Chevyfreek · May 12, 2004

Have not heard of anyone using it yet on any of the forums I am on. It may be to new of a product...

1BADHD · May 12, 2004

I have ran Mobile 1 since new. I went to get oil toay and decided to get teh Truck&SUV stuff. Figured what the hell.....Give you an update in 5000 miles!

Pancho · May 12, 2004

If you read the product guide it looks like it is made specifically for us. My only concern is the use of 40w vs. 30w. Any thoughts?

496 CUBIC INCHES · May 12, 2004

Until the M1 5-40 is available in the 5qt jug at Walmart,I'm going to stick with the M1 10-30. I ran an OCI with the 5-40 and used 1/2 quart in 5K,thats the same amount my 8.1 uses on the 10-30. IMO 1/2 qt in 5K isn't a big deal,so I wouldn't consider my truck as one that uses alot of oil.

Around here the 5-40 is $4.99 a qt. Buying M1 10-30 in a 5qt jug at Walmart makes it about $3.75,if the 5-40 ever makes it to the 5qt jug I'll switch to the 5-40 permanantly. The 5-40 is actually re-labled Delvac 1,it is without a doubt the best oil M1 sells.

496 CUBIC INCHES · May 12, 2004

If you read the product guide it looks like it is made specifically for us. My only concern is the use of 40w vs. 30w

Check out Bobistheoilguy.com,the guys over their are on the edge of insane about oil. They eat,drink,and sleep oil. They can answer ANY question you have about oil.

The reason the lighter visc oil is reccomended,is because of CAFE (corperate average fuel economy). I don't know exactly how it works,but IIRC the car manufacturer gets some kind of credit from the Gov. to produce cars with better fuel economy. The Ford V-10 is a prime example,Ford used to specify a 5-30,now with no changes made to the engine, they want a 5-20,why...to eek out every last bit of fuel economy.

Unless you're still under warranty I'd have no problem running a different visc oil in your 8.1. Last summer I even ran Chevron 15-40,with no problems other than a loss of MPG. The 8.1 needs lots of help in that area,so I ditched the 15-40 and went back to M1 10-30.

JimWilson · May 13, 2004

I like the Amsoil because I can run it for 25,000 miles and just have to change the filter and add oil at 12,500 miles. This is using an Amsoil Superduty Oil Filter....

You only change your oil 4 times in 100,000 miles?! And the filter only every 12,500?? Now you know why I don't buy used vehicles...

Chevyfreek · May 13, 2004

I guess you can look at it that way. You actaully will add oil at the filter change and you will loose some oil to vaporization. I add about a half quart 3,000 to 4,000miles so that is total of 3 - 4 quarts added over a 25,000mi time frame. So you are adding new oil to the system. Technically trans fluid and diff fluids go that long and longer, why is is so hard to believe that a synthetic motor oil can't. We all know sysnthetic oils are better so why should we have to change them as often as regular oils? Time will tell, I will see how well my truck is running at 300,000 miles on the engine...

Chevyfreek · May 13, 2004

Here are a couple of informative site on Amsoil if interested in reading up on the subject.

Performance Oil Technology

Best Synthetic.com

JimWilson · May 19, 2004

Technically trans fluid and diff fluids go that long and longer, why is is so hard to believe that a synthetic motor oil can't.

Motor oil is also scavenging waste particles left over from the combustion process, which dirty an oil very fast. Since that isn't necessary for the driveline components those fluids can last far longer.

Chevyfreek · May 19, 2004

That is true Jim and I agree with you. The thing is that synthetics are supposed to get dirty, but they don't breakdown as fast as conventional oils. They don't have the intial impurities that regular oils have, so they can last longer and maintain their viscosity even when filled with the wastes as a result of combustion. Running the Amsoil filter is a big part of the extend drain intervals as well. You will loose some oil to vaporization as the miles add up so you do end up adding some oil over the 25,000mi period. Also at the 12,500 filter change. I am by no means saying that there is anything wrong with Mobil 1 and changing the oil every 6000 miles or so. That would be great for any motor. I have run Mobil 1 in other vehicles including my HD and have had no problems with it.