I use Mobil 1 Delvac in my diesels. The diesel club in my area (for trucks) have guys who have paid tons of money just to compare their oil analysis sheets at meetings. From what I have heard from them, they seem to agree that the Mobil 1 Delvac and Amsoil are the only group IV true synthetic oils. Nobody seems to agree on which is better, the Mobil 1 Delvac or the Amsoil stuff. It seems to be a rather moot issue to me since both oils will apparently provide proper lubrication for a longer period of time than I'll keep in in my engine. Being that I can drive to my local Sam's Club and pick up the Mobil 1 Delvac for half the cost of Amsoil, you can guess what I use.
Most of the guys, and I'm sort of in that group, have their diesels turned up to produce huge amounts of power. Now, here is my theory; why would I chance a $15,000 performance diesel engine's life just to prove that my oil will last longer?? /forums/images/graemlins/confused.gif For the Cummins Fleetguard filter and 12 quarts of Mobil 1 Delvac synthetic oil, it costs me about $42 and 6 or 7 minutes of my time to change.
There is no way in the world that I'm going to go for the record setting extended drain period with my oil and chance toasting a $15,000 engine, especially when neither oil company will replace your engine if you toast it by going the extended oil drain intervals. I only drive my truck about 12,000 miles per year. I change the oil and filter every 6 months / 6000 miles. So, in a year I spend $84.00 and maybe 15 minutes of my time. Am I going to change my ways and gamble with my expensive diesel engine to maybe save $5.00 or $10.00 and 7 minutes a year?? The answer to that is a resounding *ell no! I'm not a gambler. I work too hard for my money. I'm staying with the conservative guaranteed safe bet.
I'm sure Red Line and Amsoil are fine oils. As a matter of fact, I've even tried to bid on some Amsoil on eBay to try it once in my truck. Unfortunately it always goes for way more than my Mobil 1 Delvac sells for, so I've never had the chance to try any. I'll keep trying every so often. Heck, if someone who reads this is a true believer in Amsoil and can get me a deal on 12 quarts, I'll gladly try it. I just won't go over my 6 month or 6000 mile sure thing schedule with it. If somebody gets me a great price on the Amsoil oil and is so sure that it is still good then, I'll even send it all to them to use free after I drain it, as long as they pay the shipping. I'll be finished with it.
Hey, some of you Amsoil guys, get me some prices on the oil and filters and I'll give it a fair shake. I'll even spring for a test of my Mobil 1 Delvac at 6000 miles and then get an oil test on the Amsoil at 6000 miles and gladly post the results. It won't hurt my feelings if the Amsoil proves to be better. If I can get a reasonable price on it, I'll gladly switch from my beloved Delvac. /forums/images/graemlins/grin.gif