Oil in the intake / Fitting a Provent oil-air separator / Stopping Split Intercooler hoses and CEL illuminating and Limp home mode activating
As part of the emissions control system on the CRD engine, gases that vent from the crankcase breather on top of the engine are re-routed into the air intake before the intercooler.
These expelled gases also contain a mist of oil that condenses on the hoses and eventually clogs the fine passages of the intercooler (one of the 'radiators' through which intake air travels to be cooled, situated at the front of the engine bay). Note that this is not peculiar to the CRD KJ, most modern turbo diesels have a similar system, and the inherent problems associated with it.
Blocking up the intercooler is bad news, as boost pressure created by the turbo in the intake, builds up to too high a level before the intercooler and either splits the turbo to intercooler hose or blows the pipe off one of the fittings. The oil also softens the hoses, weakening them.
The oily sludge that accumulates in the intake also contaminates the mechanical components and sensors in the intake, which can cause problems with these and the 'Check Engine Light' on the dash may illuminate, and the engine goes into 'Limp' home mode - this essentially renders the vehicle undriveable.
To remedy this situation - install a Provent oil-air separator in the line that normally comes from the crankcase to the air intake. The Provent will allow oily gases to condense within it, and you can drain the accumulated sludge out of it at periodic intervals.
The emissions control system remains in place and the cleaned gases from the crankcase remain within a closed system as designed, because the outlet from the Provent routes back and attaches to the intake where the original factory fitted hose between the crank case vent and the intake did.
Provent information is here
Yet to be fixed
A Provent is available to buy from Sydney Filters, Unit 19, 70 Holbeche Rd, Arndell Park, NSW, 2148, phone (02) 9672-7008. Their AJOR discount price was around $200 and they will ship anywhere in Australia.
Additional items will be needed to install the Provent (as it has 1 inch fittings on it and you need to reduce the hose size to 3/4inch to connect to the Jeep hoses and fittings on the Crankcase breather).
Go to Enzed or any place that sells fuel hose and buy some 1 inch internal diam fuel hose (2 lengths about 8cm each), and some 3/4 inch hose (2 lengths 1m long each) and hose clamps.
You will also need 2 black plastic retic hose fittings from the local Bunnings from the garden section. They have a threaded end on one end which is 1 inch external diam (so matches the 1inch hose) and a 3/4inch barb on the other end (for the 3/4 inch hose that goes to the CCV on the engine and air intake).
The 1 inch hose will slip onto the Provent, then the garden retic fitting will go into that, then the 3/4 inch hose will go onto that and connect to the engine. Hose clamps will go on all the connections to keep them secure. So the job of reducing the size to 3/4 hose is complete!
You will also need 1 x 19mm retic hose pipe joiner/connector so that you can connect the 3/4 inch hose you purchased to the end of the pipe that you will pull off the Crank Case vent. Its easiest to do this rather than remove the factory pipe completely - leave it attached to the air intake and just bend it around so it will meet up with the new pipe (see pics below).
Finally, you will also need a length (50cm) of half inch fuel hose to put onto the outlet of the Provent and a 12mm garden reticulation tap fitting to put in the end of the hose. This way it is a simple matter to turn the tap on to drain the Provent (with a bucket underneath to catch the oil). It will accumulate at the rate of about 100ml every 3000-5000km depending on how its driven.
Pictures of a Provent installed
Crank Case Vent and hose to attach Provent to with this mod.
Where the existing hose is spliced with a straight through connector.
Routing of the hoses to behind the battery.
Provent mounting location.
