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Right - Diesel guys, incl engineers, don't like to say the word "vacuum" - they prefer the word "depression" - a Diesel engine that is developing significant levels of vacuum in the intake is not running efficiently - usually resulting from a dirty air filter, or stuff blocking the intake path - even a convoluted ducting system, resulting from design constraints in modern vehicles.
The CCV system is a Crankcase Depression Regulation system - by creating a very slight vacuum in the crankcase - a "depression" - just a little below Barometric pressure, engine oil cannot easily pass thru a seal because atmospheric pressure is pushing against the other side of the seal, trying to equalize the pressure - the slight pressure helps to compress the seal, thus forming a better seal - if that vacuum level increases, Baro pressure will force dust, dirt, silt, water, etc, thru the seals into the engine - not good, in any event - really bad, in an off-road vehicle.
The turbo compressor inlet develops varying levels of vacuum depending on rpm and air flow, and air filter condition, and ducting path - the CCV system is designed to compensate for each vehicle configuration and regulate that varying vacuum source, such that the crankcase "depression" is within the design specs of the seals - usually 4-6"H2O @ 2000rpm.
Your engine is classified as a light-duty Diesel, which means it must comply with light-duty vehicle emissions standards - EGR, CCV, EVAP, Etc - all that stuff, most of which is detrimental to engine function, but is good for your lungs, and your descendants lungs.
The CCV system is a good thing, as blowby and normal hot-oil vapors are combusted along with that light oil we know as Diesel fuel - however, it is definitely not good for a turbocharged Diesel with a charge-air cooler - intercooler in streetese - as the vapors cool and collect inside the ducting and heat exchanger - wotta mess! - requires the 'cooler be removed, drained, and cleaned, even moreso as the engine wears and blowby vapors increase.
The Provent and similar systems maintain the integrity of the CCV system if the cannister is drained and the filter changed regularly - wotta hassle, right? - until compared with pulling and cleaning the 'cooler and ducting - the Provent system is defeated when the filter becomes black and saturated, as the slight vacuum is blocked and cannot evacuate the vapors
That area on the cam-case cover is not a good position for a CCV port, as the vapor-level is increased due to cam rotation and camlobe action - a better location would be the oil-filler tube, which has a little better isolation from valve-train splash
There is another method, guaranteed to fail emissions testing, but serves the same function without the mess - install a reverse pitot-type tube into the downpipe back towards the soot-trap - develops the required vacuum, the vapors are burned-off in the soot trap, no drip, no mess - but, you must first measure exhaust backpressure levels in the exhaust system to ensure that the crankcase is never pressurized - the old gasser (patooie!) A.I.R. systems employed low-pressure backfire valves for just such function - Diesels don't backfire, but a similar valve would block any normal backpressure
Yes, the EHM defeats the CCV system - the medium-duty Diesels use that system with larger mesh buffer-filter, but like your dog, will leave a 'mark' everywhere - the Cummins crank seal has an integral teflon sleeve, intended for dripless +200kmi service
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'05 CRD Limited
Pricol EGT, Boost
GDE Hot '11; EDGE Trail switched
SEGR; Provent; Magnaflow;
Suncoast T\C, Transgo Tow'n'Go switch;
Cummins LP module, Fleetguard filter, Filterminder
2.5" Daystar f, OME r; Ranchos; K80767's, Al's lifted uppers
Rubicons, 2.55 Goodyears
Four in a row really makes it go
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