I have a 2003 ram with the 5.7 hemi and 75k. I plan on doing an oil change. I bought 10w 30 but am unsure if it is the correct weight. I have read different things on the forum. I bought a repair manual CD from ebay and for the 02-03 rams it says either 5w30 or 10w30, but for the newer ones it says 20 weight or 30 weight. I thought the engines were the same? which should i use? According to the chart, 10w30 is fine for the temps i will be experiencing but i dont want to damage the engine. The oil cap does not say anything. I just bought the truck a few months ago and this wil be my first oil change.

 

5w-30 for yours, 5w-20 for the 06+ with MDS engines.

 

thanks for the clarification, back to autozone!

 

You don't have the tight tolerances of the MDS Hemi's, 5w-30 is YOUR recommended weight, but 10w-30 won't hurt you. I know a lot of guys who run the slightly thicker 10w-30 in summer and 5w-30 in winter.

 

I am at the exact same mileage and same truck! I heard that in warmer climates 10w30 is better? I live in Houston and it will be in the 70s and 80s into oct most likely

 

used to always be the rule of thumb, goto thicker oil in summer and on older vehilces, but the newer thought is that the thinner oils flow better. So, if it were me, I'd stick to the recommended viscosity.
That said, I run a THINNER oil, my '04 calls for 5w-30, but I have a 180* thermostat and therefor run the next thinner oil, 5w-20 in a full synthetic.