Just been given a lot of 5w 30 grade synthetic oil.
My 03 Hemi uses 10w 40.

Would the 5w do ........? [sm=confused06.gif][sm=feedback.gif]

We don't have very cold winters or hot summers here in the UK.

Al.

 

If I am not mistaken your 03 Hemi is not 10w-40. I know they changed to 5w-20 in 05, but I think it was 10w-30 before that, others can chime in.

 

I have an 05' Hemi with several performance mods and 10W - 30W Mobil 1 works very well for me in the Texas temperature extremes so you should be ok with a good synthetic***

 

the big thing is not what the wieghts of the oils are but the difference between the two. a 10 w 40 has a lot lot more polymers and additives to give it the properties that make it that thick at warm and that thin at a cold temp. these polymers can be harmful in the long run if the engine isn't made to be run on it. the 5w30 will have less polymers in it than 10w40 the only difference is that it'll be slightly thinner at cold and warm temps. I can't remember what temps those measuremtnes are taken at. for some reason 32 and 70 degrees F are sticking out but not sure.

 

'03's were recommended 5W-30 by the manual, with 10W-30 being an option.

 

thats what my manual says too i use mobil 1 5w-30

 

Great, I'll use the 5w 30.
Ta for the help guys.
Al.

 

yeah my 04 says to use 5-30 in the owner's manual, oil cap and service manual lol

 

The way I understand it is all Hemi's pre-MDS are 5w 30 and MDS are 5w 20...

 

My 05 calls for 5w-20, I just checked. Does that mean mine is MDS? The salesman said it wasn't. When did MDS start?