I read the following in Diesel Power in regards to the new Diesel Engines from Cummins:
Low-Ash Oil
Like all '07 emissions-compliant diesel engines with a DPF, the Cummins V-6 and V-8 will need to use CJ-4 low-ash oil. This prevents the DPF from becoming clogged, its more resistant to heat, and produces less sludge and soot than conventional diesel blends.

Historical reference: Back in the late 1950 and early 1960s, International Harvester had problems with engine deposits in their gasoline farm tractor engines. Research determined the hard deposits were due to the type of detergent used in light duty automotive oils of the time. To solve the problem, they had a Low Ash oil produced and sold it at their dealers. Deposits I have seen in TDI intakes and in pictures of CRD, and BMW diesel intakes like the one my Son owns look a lot like the ASH deposits that IH found in their engines.
In my humble opinion, using Low Ash oils that will meet the new Cummins requirements along with use of a Provent type device will reduce or eliminate the intake fouling we have seen. I have no plans to reactivate my Boogie Man Gas Elimination Valve, but I will want to go to a Low ash oil as soon as I can get it at a reasonable cost.

I suspect that as soon as the V6 and V8 engines find a home under the hood, oils that meet the requirements will be on the shelves and sold.

Does any one know if the oil they love currently meets the Low Ash requirement Cummins will require when their engines get on the road

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2006 Pearl Green CRD
Magnaflow 2 1/2" Cat Back
KJ Extra Leg Room Brackets, Carter Lift Pump, V6 Airbox, ORM
Fuel cooler, Oil Separator, Progard 7
Gauges EGT Boost Trans Temp Oil Pres, Michelin LXT AT2 245 70 R16
7,000# Draw Tight hitch, PML EX Deep Trans Pan
Centrifuge, SunCoast, Transgo, RAM TCM, InMotion Stage 2
Wife's 99 TDI VW Beetle

Most 5w40 sold in the states is cj4 compliant already. This would include Rotella and Delvac-1. Provent will do way more good than low ash oils. Low ash cj4 oil was made so dpf's could be used without plugging them with ash deposits from burning oil.

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2005 sport crd-SOLD No regrets

All of the synthetics available these days are very low in ash. Amsoil used to have a higher ash content because of the higher levels of phosphorus which they used as a lubricity additive. Their new CJ4 diesel formulation does not have very high ash. The mobil 1 recommended by Jeep is also very low in sulfated ash.

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Manure green 2005 CRD sport4x4, GDE Hot tune, Cat Gut, OE skids, Draw tight hitch, Duramax lift pump, 160K on multiple varieties of fuel, XM radio, Escort live with Redline, fog light mod, GPS, Icom IC7000 all band radio call sign KC9QPF, Grabber AT2s on Soft 8s, FIA grill blanket.

I've been pouring this in the crankcase of the KJ...

Mobil Delvac 1 ESP 5W-40 http://www.avlube.com/fonfacsizcol.html $148 for 4 gallons.

Since I got the WK 3.0L I've decided to switch to this...

Mobil 1 ESP Formula M 5w-40 http://www.avlube.com/mo1espfom5wc.html $41 for 6 quarts.

Whodda thunk the special Mercedes stuff would work out to be cheaper than the big rig bulk oil?

'Course the WK gulps it down 10 quarts at a time for a change vs. 6.3 q for the KJ. And I notice one case won't get me there with either engine so I'll have partial cases lying all over the garage...

I have no idea if it will cut down the crud in the intake of the KJ. But I have it from another LOST person that non-certified low ash oil will eventually crud up the 3.0L engine in a Sprinter.

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2005 CRD Limited Flame Red w/ Renegade rock rails & light bar, AirLift 1000. 225/75R16 MT/R's on cheap black steel wheels, dual MOPAR subwoofers, Ipod kit & seat covers, Samco hoses - totaled and gone. 2008 WK Laredo 3.0L diesel - AirLift 1000, wife won't let me mess with it much. 2013 JK Sahara on order.