Is it okay to switch back and forth? Or will things blow up?

I think right now I have 5W-40 Synthetic, but I was considering using 'ol Rotella 15W-40 on my next oil change to save some money.

 

there are some that will say putting synthetic in an older truck that hasn't run it before will show leaks, I really don't know

my truck always had rotella but I put synthetic in it for one oil change at about 150k miles, worried about it, drained it and switched back to rotella and I am staying there, 200k miles and it doesn't use or leak a drop

 

There really shouldnt be any problem. I sure all of what we read/hear about that are horror stories.

 

I have run the Rotella 5W-40 in the winter and switched back to dino juice for the summer. Didn't start any new leaks.

 

I use the Castro Tection Extra 15w-40. Good stuff.

 

Ditto with my old MB, the utility truck, and the dually. The 5W is MUCH better on cold cranking.

The dually already leaked plenty so I'm not sure if it mattered much!

 

Since the molecules of synthetic oil are smaller than dino, it will "find" a leak earlier than dino. That doesn't mean the synthetic caused the leak, you would have had the leak eventually anyway.

Amsoil is completely compatible with dino. I could look it up if you want.

 

I know you live up in cold country and the syn. oil should help on cold starts. We tore down an engine last week 1,400,000 and had never run anything but rotella dino oil. The bearings still looked good. Just my opinion on Rotella 15 w40.

 

I use valvoline cummins blue oil, I have hurd its not a good idea to switch back and forth. But if you use a quality oil and change it when your suppose to I dought it would hurt anything.