Of course our CRDs don't have a PCV, and burn a different fuel?

Where did you acquire this little piece of information from?.

They have a CCV, not a PCV. CCV is crank case pressure, PCV is vapors drawn by engine vacuum, with lots of flow. Unless they don't do this any more, I have not owned a gasser in so many years I am kind of clueless. Any ways, I was thinking my TDIs had no sludge under the valve covers either.

anyone had any sludge or oil pump issues ? I had what seemed to be a bad oil pressure sensor late last winter. I installed a new sensor and it has been fine until oil change last week. Last winter oil change was from Mobil 1 to Rotella T6. Last week's oil change was from Rotella T6 back to Mobil 1. Now I am getting oil light again for a few hundred yards when I start out with an overnite, cold engine. Could it be that Mobil 1 is cleaning out the sludge and blocking up the sender unit ? (There are no oil leaks and crankcase is full). Is there that much difference between 0w-40 and 5w-40 cold viscosity ? Theoretically, the 5w-40 should flow better below freezing. So, am I looking at a sludge blockage, or another bad sending unit, or, worse, a worn oil pump ? Truck has 95,000 miles on it. I will be changing back to Rotella at next change and see what happens. (engine is quieter with Rotella)

The oil pressures switch is a standard Chrysler issue, not a Quality Bosch or VM component. Your oil pressure switch may be junk and causing the light to come on. Unscrew the switch that has 1/8 inch National Pipe Threads and screw in a gauge and check the oil pressure. You will need to fast finger the switch out and install the gauge so you don't have oil running out of the oil gallery, it will not drain the pan. My test gauge has a 1/8" NPT grease gun hose attached to it to allow it to get into tight spots. A cheap gauge from Home Depot or the Hardware Store will work for the test.
If the engine is not clicking from too little oil pressure to the lifters or knocking, chances are good you have a bad switch, but no guarantee until you test.
Also check the wiring to the switch, it may have gotten caught and skinned so the wire to the switch shorts out to ground.

What DCX calls a "CCV" and a PCV are one and the same. Any crankcase venting system which has a one way flow is considered a "Positive Crankcase Ventilation" system. See the note on Diesel Engines in this link.... http://en.wikipedia.org/wiki/PCV_valve

But diesels don't have this



"Positive Crankcase Ventilation Valve", because diesels don't create vacuum. OTOH Gassers do create vacuum, they are constantly drawing air through you engine from a breather filter, to the vacuum supplied to the PCV valve. I wonder if the air passing over the oil oxidises it, and cause the vapors to turn to sludge. I have seen plenty of sludgy gassers the most sludge is under the valve cover with the PCV valve, but I have never seen a sludgy diesel? Has any one seen a sludged up diesel before?

Re: cold weather and which oil flows better

Thanx for catching that.....I meant to say 0w-40 should flow better tha 5w-40

flman: What sort of environment do you think exists between the restrictive air filter and the turbocharger? Here is a hint: it's less than atmospheric pressure and more then outer space. Remember that this is where the CCV/PCV vents to on our CRDs. The only venting difference between a turbodiesel and a gasser is that a gasser has the highest vacuum while at idle with the least amount of blowby, A TD has the highest vacuum when at WOT and the turbocharger is working hard. This also happens to be during the period of highest blowby which is why we have a built in labyrinth oil separator (which doesn't work) on our Jeep's PCV.

However, this is probably immaterial to the question at hand. The reason that we see much less sludge in diesels is the superior oil used as well as somewhat lower crankcase operating temperatures (except in the turbo, where coking can occur). Diesel spec oil has vastly higher amounts of detergents as well as a vastly higher TBN which all contribute to extended change intervals and less polymerization on crankcase surfaces.

turbobike: Why do you say that 5W-40 should flow better in cold weather? I notice a substantial difference with the ease of starting between the M1 0W-40 and the T6 5W-40. The easiest to start at <-30 seems to be M1 0W-30.

I had a bad oil filter once that presented as you describe, changed filter and never a problem since. The filter was from Chrysler