So I did the "key dance" to check for codes. It just says "donE", so no codes are being shown/recorded.

Does this also mean that if I connected the Snap On tool that it will show as "no codes"?

 

Did you do the oil change yourself or have a shop so it. If a shop did it, any chance they screwed up and put in the wrong weight oil even if you requested the right stuff? Just a thought.

 

You are not going to show any codes unless the CEL has been on at some point.

 

I did the oil change myself with 7 qts of 5w20 Castrol and a Fram filter.

 

Great news!! It's fixed!!

The short:

I changed the Fram filter for a Mobil 1 filter. I have not topped off the oil but I will check it in the morning when I have time before going to work.

I appreciate everyone's help.


The long of it:

So as I was driving home, I said to myself "why not give it a go full throttle and see if things behave differently." So from a stop sign, I gun it to 65mph, then I let off.

Strangest thing is that after letting off and I was coasting, MDS turned ON!! I thought wow, I fixed it. But as soon as I came to a stop, then drove normally once again, it would not stay on while coasting. grrrrr.

As I continued on my way home, I noticed my oil pressure was way lower than normal. Normal for my truck is right in the middle of the gauge when I've been driving for over 30 minutes in city with any throttle application. This time, it was only a quarter from red no matter what throttle application I gave it.

I got scared into thinking that the oil filter collapsed, clogged, or sensor was defective. I went straight to an auto parts store, bought a Mobil 1 oil filter, and said to myself, I'm going to change this and see if it makes a difference.

Also, after I had my WOT run, MDS didn't kick on AT ALL!! This was during the time that I noticed my oil pressure was lower than normal for my truck and I was super scared something serious was wrong.

After I got home and let the truck cool down a bit, I changed the filter alone. I'm not sure how much oil I lost in the process, but it really wasn't much in the catch pan.

This morning, I drive it, and what would you know, MDS returned to normal 100%. I can coast at 20MPH with the MDS light on and the beautiful tractor sound confirming that I'm using 4 cylinders.

I'm super happy that it wasn't something complicated. I"ve learned a great lesson and hope to pass this on.

If you have a Hemi with MDS, not only is oil weight important, but the quality of oil filter is just as crucial!

 

MDS actually uses the oil under high pressure to depress the pins in the MDS lifters so they will collapse. If the filter media collapsed and was resitricting oil flow it could prevent MDS from operating properly.

 

My thoughts exactly based on my experience.

Oh, and I filled up with 87 for the first time. I thought you might like that since you convinced me of it.

 

And I'd like to add that since I wasn't coasting in MDS since the last fill up, my MPG has dropped from 15.3 to 13.1. In my case, it makes a big difference.

 

Glad to hear you got it fixed, and it wasn't anything major! I would not have guessed the oil filter, but it makes sense when thinking about if afterward.

Good job!

joe

 

Thanks Joe. I'm happy as well it wasn't anything major.

Hopefully others will think twice before doing an oil change on their Hemi.