I went out and bought 5W20 for my 2004 Ram thinking it was an option. After looking at the manual, it recommends 5W30. I also thought I saw people using 5W20 in non-MDS Rams, but must have been mistaken. My question is will the 5W20 do any harm, or should I return it?

 

no 5w20 is actually better because it is thicker, you will get better oil pressure, and not have to warm the engine up as long.

 

It should be ok, especially now that summer is about gone.

 

I also agree, it will be OK. 05 Hemis (non-MDS) call for 5w-20 as well. I think they switched to help the "hemi tick".

 

you got that backwards, 5w30 is thicker (once warmed up).

Regardless, you'll be fine. And the second number has nothing to do with the weather outside, as that is the viscosity once the oil (engine) is warmed up, not when it is sitting cold in the oil pan.

 

I've been running 5w-20 Royal Purple ever since I went to a 180* thermostat with no issues whatsoever. Like stated, the '05 which is identical to the '04 calls for it anyway.

 

where did you find a 180 thermostat ?

 

i got my 180 from summit racing

 

I use 5w-20 in the winter, the tick disappears sooner.

 

Mine has the same tick, i think its the fuel injectors i am hearing, i have the 4.7, on mine