Anyone using their 15W40 ? Opinions ?? Price is around $28 a gal,anywhere cheaper ?Thanx

 

For the price and features, I would rather run and use Amsoil.

I just swapped over the Amsoil 15W-40 Heavy Duty Diesel & Marine a few months ago and have noticed a 0.3-0.5 MPG increase.

 

I know a few guys using Royal Purple and they like it. I personally like Amsoil.

 

A thread just ended about RP a couple weeks ago - try a search to find it. I used RP 15w40 for a long time and it is great stuff. I think the syns are worth the money but doubt they are necessary for engines. I know of plenty of gasser that went 250k+ no problem on petro. It's all relative! I've been using Schaffer semi syn and got a great UOA and it's cheaper. Craig

 

I have used RP for about the past 110k miles. The longest I've had it in was a tad over 25k miles and the Lab results showed it could go longer. I'll stick with it.

 

You will probably get just as good results from Rotella, Delo, Delvac, or Valvoline.
At a much lower cost.

 

It will more than pay for itself if you use a bypass and do UOAs and you can also run the fullflow filter a lot longer but if you only plan to use syn and do no other changes it's more than you need to spend. I'm still not saying it isn't worth the price. It is worth it IF you do everything else right! Craig

 

If you're going to run a bypass filter, then use the syn. if not stick with Rotella, Valvolene PB, Delo, or Delvac dino's. You need to go long change intervals with bypass to make the Syn's economically make sense. JMO

Wood

 

i ran it in my 03 cobra i run it in my diesel my boss runs it in all his duramax's they have 90000 on them and pull 20000+ everytime they go out no problems plus the fs2500 for extra insurance

 

Just use Amsoil, and don't worry about which one to use anymore.