Will changing the oil from 5W-20 to 5W-30 damage the engine with MDS? I read on the internet that if you put in any oil heavier than 5W-20 will shut the MDS off. I just wanted to know if there is any truth to this. Thanks

 

I've seen this mentioned several times here, and the caution was always to stay with the 5W20...so I do. It's my understanding that using the heavier oil will affect the MDS adversely.

 

What effect does it have if you don't have MDS?

 

According to the manual, the 2500/3500 (no MDS) takes 5W-30, and the 1500 (which now all have MDS) takes 5W-20.

 

Maybe this is where the theory comes from, but I cant imagine the switch in oil alone would trick the engine into shutting off MDS. I would think a setting in the computer would also have to change. In any case, I am sticking with the manual and using 5W-20.

 

My 4.7 has MDS?

 

Use 5w-20

 

Ive used 5w30 and there was no difference on how the MDS performed.

 

No, I was referring to all HEMI's, sorry.

 

Well, I see the forum is still broken.