Just picked up my first diesel yesterday and I have many questions. The first one is what is the best brand of diesel fuel to use in my 2003 2500 dodge ram??<br><br>My second question is what is a good speed or rpm to cruise at on the highway without a load. The reason why I'm asking this is because at 70 mph I'm taching out at 2200 rpm and redline is 3100 rpm that can't be good. The reason I got a diesel is because I drive a lot of highway miles but I don't want to cruise at 60 mph. And I've also heard that it's not good to let your diesel idle for more than five minutes. Will it harm the engine if I let it idle for a while? I thought diesels could idle for hours?? <br>Your help is much appreciated. Thank you <br> <br>

 

Welcome Calvin.
As far as diesel fuel, you need to find a station that has a high &quot;turnover&quot; of their diesel fuel. Diesel that stays too long in the underground tanks can develop problems with alge that will make you :'( Fill up where the &quot;Big Rigs&quot; do, or check with other local diesel owners in your area for a good spot.
The sweet-spot for the pre-ECHO Cummins was between 1900-2100rpm, that's where the Beast likes to run.
Above that rpm range is ok but your MPG may suffer.
As far as idling, it's ok for longer than 5-10 minutes if you keep the rpm above 1200 rpm to keep engine temps up to prevent cylinder wash from excess fuel, and varnish forming on the valve stems.
I use a stick, cut to length, to wedge between the throttle pedal and the seat to give me 1200 rpm.

Ed

 

Use diesel fuel from a station that has a high turnover of fuel. I usually try to hit the truck stops. Brand really does not matter. Prolonged idling can damage your diesel. The big rigs run at high idle speeds to keep unburned fuel from washing the oil off the cylinder walls. Our rigs really are not designed for that. My 97 with a 4.10 axle ran around 2700 rpm at highway speeds. Since I was concerned I contacted Cummins who stated that the B5.9 marine diesels run at 3000 for days at a time. So no, it doesn't hurt them; and 2200 rpm is just a walk in the park for these motors. Enjoy your new diesel.

 

This web site is great!!!! Thanks for the help guys. I'll be talking to you soon.

 

;D Greetings, Calvin - good to see you here. ;D<br><br>Just my .02:<br><br>Best fuel: Whooo-wee, that's like asking what's the best oil! But, seriously, the general rule of thumb is to buy your fuel from a newer station that has a volume product turnover. Older tanks can be shedding their insides. And, fuel that's been sitting awhile sucks in water.<br><br>High RPMs: Heck, won't hurt your engine - just your fuel mileage. Typically, the best MPG obtained by Cummins 5.9L diesels has been with RPMs right around 1800-2000. I turn 1900 RPMs at 70 MPH with my 35's and am currently getting 19.1 MPG with Winter fuel (unloaded). <br><br>Extended Idling: Yup - don't do it much. It's actually best for these engines to just start it, and move off slowly 'till she comes up to operating temps. I'm not saying never let it idle for a bit - we all do that occaisionally. Just don't make a habit of it. And, if you do, change your oil more often than the specs require.<br><br>--------------------<br><br>Calvin - what you're going to run into on this site are a lot of compulsive types who obsess over their beloved trucks (guilty as charged). But, don't let that convince you these engines aren't tough and need to be babied. These same engines get abused in civilian and industrial applications for hundreds of thousands of miles in some of the worst environs and do just fine.<br><br>Best to y'all<br>Bill

 

Don't forget that the 2003 have a high idle in them that kicks up to 1000 rpms below certain temperature, works good on mine.<br><br>Also on the &quot;old&quot; stations having worse fuel. Don't know how the rest of the world is but here in WI a couple of years ago ALL stations had to pull any steel tanks and replace with plasitic or close up shop, so the rusty tanks things here any way is a myth.....

 

Red Line makes a nice Diesel additive that I find helps the fuel mileage a little. It boosts the cetane rating and helps prevent algae from contaminating your fuel system. As for running at 2100 rpm for long periods of time - it's really about the best rpm to run at. Most engines, gas or Diesel, develop their best fuel mileage at between 65% to 75% of the red-line rpm. That works out to between 1995 and 2325, so you see that you're running right at the &quot;sweet-spot&quot;. You can run it right up to red line, but at others have stated, you'll find your fuel mileage suffering. Enjoy your new ride and welcome to the world of Diesels.

 

Good info guys.<br><br>I'm a newbie too.<br><br>Just got the toy today and like it a lot.<br><br>Good advice on idling. I also heard that getting a water/fuel separator is a good investment, but haven't really looked for one yet! ;D

 

Do all of the 03's have this high idle function?

 

TexasRam,
The fuel filter canister is also a water separator on most of the CTDs.

 

Texas Ram<br><br>You all ready have a water separator along with a valve to empty the water. <br><br>Bob

 

Yup...you guys are right!<br>I found it in the manual yesterday!