I had a 2004 with a vibe problem and got another in May that doesn't have the problem. My only question is I noticed that the oil in the first 04 never got black (stayed very clear between changes). It got great milage 18-21 but had the vibe problem at 2000 RPM. My new truck has about 5K miles (1 oil change) and the oil gets significantly darker in appearance than the first truck. My mpg is between 15-18. Why the big difference in oil condition? I guess the lower mpg is due to the new 600 performance.

 

Could it be that the first truck had synthetic oil in it? I've heard (but never had any solid confirmation) that you can't put synthetic oil into an engine that hasn't been broken it yet because synthetic oil is too slippery and won't let the internal parts wear like they need to.

Anybody agree?

 

Your right about using synthetic on the break-in. I think your current oil is darker because the newer engine is a little higher performance, so more fuel is given to it which makes more carbon. Even with 200,00 miles, my oil took some time getting black, until I turned the pump up.

 

if you have a kind of a vibe ........is more noticable in high gear???can you asso it with a noise??

 

You may be right about more power creating more blow by and increased contaminents in the crankcase. I would really like to get back to a cleaner crankcase and better fuel milage. In my opinion the increased performance is not that significant to sacrifice the milage and oil condition. Does anyone know if they can de-tune the engine back to the specs of the 2003 and early 2004 engine?

 

Are you using the right oil? You can't use the same kind of oil as you use in a gas engine. It needs to be an oil that can handle the acidity created by the sulfur in the diesel fuel.

De-tuning shouldn't be the answer. The Cummins is made to produce 500 HP and 1000 ft-lbs torque...the way they're tuned from the factory already IS de-tuned!

 

I used Shell Rotella 10-30 in both vehicles. I am thinking that the increased power of the 600 may be the cause. I plan on doing an oil sample analysis at the next change out and maybe switching to a synthetic (Mobil 1 has a 10-40 and Valvoline has a Cummins tested 5-30), provided the engine is broke in. I have 6700 miles on it now but will probably wait until 10,000 before putting in a synthetic. Any thoughts on this?

 

Bill,
I think the recommended oil for the CTD is 15W-40 with a CI-4 rating.

 

It is strongly recommended you use, at least a CG-4 rated diesel oil. Better yet,use the newer rating (for lower soot contamination) - CI-4.
In your part of the country I would use one of the 40 wts; 5w-40, 10w-40 or 15w-40, especially in the summer.

I live just north of Dallas and run a very high quality, synthetic, 5w-30 wt yr round. My rings are well seated but when I play with the power it won't hold the 30 wt. even though it is well broken in and very tight.
If using a national brand, non synthetic, I feel you will get cleaner oil due to a better ring seal on a new engine with a 40wt oil.

Welder 27 - You can break in a new engine with synthetics! They are NOT more slippery, just more heat resistant. It just takes longer so why spend the money. I have never heard an official reason from Dodge as to why they use to recommend against synthetics for several miles (20,000?).
Warren Johnson, NHRA PRO Stock Champion, and master guru, told me he seats rings w/ synthetic because he runs synthetics...would not say why he thought that was important. But, the point is he would not break in a new engine with synthetics if it did not work fine, or even better!

Lots of misconceptions floating around about synthetic oils. The only true benefit of a synthetic, that I am aware of (16 yrs in blending synthetics) is the thermal stability; they handle higher temps without thinning out and breaking down...which means to all of us - they last longer. This thermal stability also means they protect better when towing heavy, running higher H2O temps, loosing a fan belt, getting a radiator leak, drag racing, loosing oil pressure, etc. In other words, if and when we need them most!

RJ

 

I made an error, I am using 15-40 Rotella, not 10-30. I will definetly be looking into this further. My only experience with synthetics has been very positive. I switched to a Castrol synthetic blend in my 6 cyl. boat engine and noticed easier starting as well as improved top end speed.

 

Well, that sounds cool! Now why don't they just lower the price of synthetics a little so we can all get in on the game?