DOES ANYONE USE MOBIL1 5W40 FULL SYNTHETIC? IT SAID THAT ITS APPROVED FOR THE CUMMINS ENGINE. I TRIED ROTELLAS 5W40 BEFORE AND IT BROKE DOWN IN LESS THAN 3K MILES.

 

I do. Seems to work fine. Haven't had it tested though.

 

What do you mean by broke down? Did you have an oil analysis done on it?

 

Multi-Vis oil that has a spread of over 25, ie 5w-40 has a spead of 35, tends to break down fast on the high (ie 40 side)
You are better off using a different oil during the time of year when thinner oil is of benifit and using 15w-40 the rest of the year.

 

I agree with infidel, 15w-40 is better for summer, on that same note, Mobil 1 "Truck and SUV" is re bottled Mobil 1 Delvac Synthetic.

Mobil 1 Delvac has one of the best reputations there is when it comes to synthetic oils. It is a true group IV fully synthetic oil. Many an oil analysis has come back after 10,000 miles with the statement "engine oil within spec OK for continued use recheck in xxxx miles". Especially with a bypass filter setup. Usually the only recommendations are to change the filter, add the difference to make up the loss from the filter and recheck later.

While Rotella T "synthetic" ain't bad, (especially at the walmart special price of 12.88 a gallon instead of the "normal" price of 18.88) it is a group III motor oil. Even though it says "synthetic" it is actually a conventional base stock that has been "cracked" to give it "synthetic" qualities.

Same goes for Castrol syntec. It is a group III oil. I hate how the marketing strategy is really a lie to the consumer.

IMO Mobil 1 delvac 5w-40 (Mobil 1 truck and suv) is one of the best oils out there for diesels. Hope this helps, Kevin

 

Heck, my truck has had the oil changed every 3K miles with Mobil 1 since new. My engine should not wear out anytime soon!

 

Dargo, go to 6000 miles even 8000 mile change intervals and put that money in yur pocket!! Man your throwing away good oil!! Of course I don't know how hard you drive, but I would seriously consider an oil analysis just to prove it to yourself. Heck send the oil my way!!

I bet you will find that you don't need, in fact I know you don't need 3000 mile change out intervals on Mobil 1 delvac. Unless of course your dragging 2 fords and chevy behind you .

Heck the money you save will add up to some nice mods, but then again, it looks like you have that pretty well taken care of. Kevin

 

Read this article:

http://www.caranddriver.com/article....&page_number=1

This is just a small part of that article By Car and Driver, and based on deposition from a trial by Mobil 1 vs Castrol:

"The notion behind synthetic motor oils as we've known them is an elegant one. Instead of relying on the cocktail of hydrocarbons contained in crude oil, why not go into the laboratory and build the perfect base stock from scratch, molecule by molecule? The synthesizing of PAO starts with ethylene gas, a simple two-carbon molecule, and builds till it gets 10-carbon molecules, then combines three of those to form PAO. The result is a fluid more stable than the usual base oils derived from crude. It keeps flowing at low temperatures. It's more resistant to boiling off, and more resistant to oxidation, which causes thickening with prolonged exposure to high temperatures. "

"Still, there's more than one road to the point B of improved stability. Petroleum refiners in recent years have learned how to break apart certain undesirable molecules -- wax, for example, which causes thickening at low temperatures -- and transform them by chemical reaction into helpful molecules. These new hydroisomerized base oils, in the view of some industry participants, "provided properties similar to PAOs but cost only half as much," Lubricants World reported."

"break apart certain undesirable molecules " is what the term"cracked" means
.

If you really want to bone up on the various types of oils out there then check out this website:

http://theoildrop.server101.com/ubb/ultimatebb.php

Tons of info on all types of oils, lubricants, grease, etc. Not sure on valvoline. I can't say for sure. I THINK valvoline premiuim blue is grp III and Extreme premium Blue is group IV, but please don't quote me on that. The website www.bobistheoilguy.com will give you the answer. Hope this helps, Kevin

 

yes i had an oil analysis on rotellas synthetic 5w40 when i used it a year and half ago. i wasn't at the 3,000 mile mark and i noticed blue smoke like crazy coming from the exhaust. i dumped the oil and and sent a jar to blackstone labs and long story short the oil was rotten. as soon as i went back to mobil delvac 1300 i have no smoke, no discolored oil or anything like that.

 

Shell had a bad batch of Rotella syn that they offered refunds on. Guess it had a real bad rotten egg smell right out of the jug. Perhaps that's what you got.