d6lc

So my 170k 2001 4.2 in the last 2k has stated to burn oil, when I first got the car for the first 5k it didn’t seem to burn any oil at all. So I was surprised when I checked it lately that it is going through around ½ qrt in 1,000 miles. I know this isn’t bad, just miffed that it started all of a sudden. Cant see any leaks, so I presume it is burning it.
On checking a few threads, some seemed to find that replacing the PCV helped their oil consumption, so I removed my PCV to have a look at it and to my shock it was totally gummed up, I am pretty sure that it is the original unit so 12 yrs old. When I tried to take it apart the housing split with the case being pretty age hardened, so I have ordered a replacement and will fit it.
I also see comments on threads regarding a Pressure regulation valve, does a 4.2 have one of those (as well as a PCV?) and if so where is it situated?, I had a look through the Bentley manual and it wasn’t clear.
As the PCV was so gummed up I just wandered if there were any other components in the system that need cleaning/replacing?

Airbag

i thought the pcv on these cars was a plastic thing that couldnt be taken apart ? looks like kind of a plastic Y sitting on top of the engine at the back .

d6lc

yes it is a plastic disc ~4 inchs in diameter x ~1 inch deep, it is clipped together. On taking mine apart it split as the plastic was brittle

Airbag

oh then they must be completely different to mine.

Redneck Truck

The following assumes you have done no maintenance to remedy oil leaks. In the valley under the intake manifold is a cover plate, and below that, an oil separation plate. The gasket for the oil separator is built in, so unless you can find a replacement, the cost is some $150. While you're in there replacing that and resealing the valley, check your oil check valves under the plate (8- or 10mm Allen), your coolant pipe o-rings, and your knock sensors. I replaced all that stuff while I was in there. Also, if there is a good bit of sludge buildup in the valley, it is a good idea to pull the valve covers too and see how sludged up they are, as it may be worth doing a manual cleaning. if they're bad, check under your cam chain tensioners too. While the intake manifold is off, clean the ports (turning engine over at each cylinder to clean ports with closed valves only), runners (to the extent you can reach them), and throttle body with brake clean or equivalent, and test the function of the intake manifold changeover flaps (they get sticky). Also a good time to check function of EVAP purge valve and suction jet pump (y-shaped vacuum valve on back of motor) and all vacuum lines and replace as needed. There is no pressure control valve unless your 4.2 is an RS6 :-)

I'm sure I am missing something, but the bottom line is, this is an opportunity to tackle all systems that reside in the same place at once.

Edit: there is a fuel injector pintle cap, o-ring seal, and internal filter kit on eBay for like $20. When you pull the fuel rail, you'll break a few of those caps. Easy replacement, but a big pain if you don't have one on hand. Also, make sure your fuel pressure regulator is functioning properly. At very least, check for leaks. I sucked air out of mine and tasted fuel, so I knew the diaphragm had leaked a bit and it was a matter of time until it collapsed. Replacement was only a few bucks and worthwhile to know with some certainty that system was functioning.

kapkanimd

did you have to get a factory replacement or do you know of somewhere else to get them? a few places I have checked don't carry them for these cars

mike2112

d6lc

Got one from ECS, I think it was around $65 with shipping, havent done many miles since fitting but I think it has improved the oil consumption