high mileage oil and bosch filters

[M. Sage]

Have any of you tried running 15w40 through gasoline engines? I was given a few gallons of Mobil Delvac and told that it is good to run in the summer heat. I haven't really tried it though because I don't wanna screw anything up. I know that it's HUGE in the diesel industry, but there's gotta be a reason my manufacturer recommends 5w30. I just wanted to see if anyone on here has seen any negative or positive results from using the diesel grade oil on a gasoline engine.

It doesn't help. Funny enough, oil temps don't fluctuate that much between winter and summer on a hot engine (not in a water-cooled engine, anyway). The big difference is cold start. You can get away with a slightly thicker oil in the summer because the oil won't be as thick as syrup when you start it in the morning, but 5W30 is still going to be better cold and almost no thinner hot.

If you want the best of both, 0W40.

 

[Shotgun Jeremy]

Ok, that's the answer I was afraid of. But when you work in a shop and you have a whole group of "experts" telling you something, it's kinda hard to argue and it also gets in your head as a "what if".

 

[40Arpent]

lol!

just to be clear, I don't work AT a Jiffy Lube, but the company I work for owns JLI.

 

[Shotgun Jeremy]

So what did Jiffy Lube do to clear their name? They had a bunch of black-eyes after that IR that was pretty much nation-wide.

Also, I got lazy last oil change and let the local Midas do it. Screw them guys. The one I used to go to in Cali was pretty good. But this shop-I had to get a 1/2 breaker bar out to loosen the drain plug, and I still can't get that damn oil filter off of there. It's in a spot that you can't get it with a strap wrench, so I'mma take it back and let them take it off. Then I'll put the new one on how the instructions call for. This is the first time in 3 years I haven't been able to break my filter loose by hand.