my 3500 ram with the 5.7 hemi has a slight knock it did just knock at start up but i changed the oil and now it knocks all the time and it has code p0430 and p0420 it has 115000 miles and i change the oil ever 3000 - 4000 mile i use mobil-1 5w20 any help would be nice thanks

 

That oil's too thin for an '04. I bet if you switch to the proper weight, it'll stop (providing that knock is lifter click). Those codes are "Catalyst efficiency below threshold..." Banks 1 & 2

 

you have a 3500 with a 5.7 hemi in it??

how's that possible.

 

i was told by the dodge dealer that it takes 5w20 i will have to check it out at make for sure but what oil should i use ........ and yes you can get a dodge ram 3500 dually with a 5.7 hemi

 

2500 and 3500 are both available with the hemi. They make a little less power though. 330 hp I believe.

 

You have a dually with hemi? I bet you get great mileage. Anyway, Welcome to DF.

 

Wow learn somthing new everyday I guess.
I thought you could only get the cummins with a 3500...
Thats pretty wild.

I know i put 5w20 In mine (Mobil1 as well)- that's what it calls for. Doesnt knock.
Mines an 05 though, I dont know if there is much difference between the two years.

I know this is off topic- but im interested in findin out what kinda mileage your truck gets. Hows that 3500 do with the hemi?

 

The '04s need 5w-30, I believe. My '03 specifies it. I don't have an '04 shop manual. Most the MDS-equipped trucks need 5w-20, and that's the '06 and newer 1500s. Isn't it marked on the oil fill cap?

 

I would guess the Hemi's puffin' a bit to move that much truck. With the reduced HP, did they get more torque?

 

it gets aboout 16.7mpg on the highway , about 12mpg in the city and it pulls great but gets about 9 mpg it ran a 15.9 at the 1/4 its stock with 5 speed auto r/c