I have searched for, but cannot find, a posting about how to clean the Part Load Breather (PLB) on my 1999 XK8. It involved using a specific size drill bit that was inserted into the PLB to prevent pressure build-up and subsequent oil leakage around the cam covers.
Does anyone know the procedure and will post it?
Thanks

 

http://www.jagrepair.com/images/TSB/...20Breather.pdf

 

There’s a lot of experience on this forum concerning this part. Beware that’s it’s an old plastic pipe that has been cooked in the engine bay. Go gently, as if it breaks, replacing the part needs removal of the air intake manifold.

 

Good advice from David. If you break the pipe, you can rejoin it with some shrink wrap used to seal soldered electrical connections. I have a good selection in my shop, was able to find a perfect fit.

 

Be careful not to let go of the drill bit. I did, but luckily I was doing it while I had the valve cover off the engine, so not too hard to recover ( there is an enclosed space inside the valve cover, with some filtering medium). No way to get one back without taking the valve cover off.

 

Looking at the TSB linked above, it says that the last affected VIN in sequence (for XJ8) is F25708, which falls in the middle of the 2001 MY production range. My VIN ends in F29932 but is an '01 XJ8.

Does anyone have knowledge as to what, if anything, Jaguar did to address this issue during the MY that would negate the need for me to clean the part load breather hose every 10K miles? Like many others, I don't have the magical connector clip that would make removing the hose much easier. If I'm not required to clean the hose, I'd rather not mess with it and avoid breaking the hose.

 

I need help with the part # of the connector / junction for the part load breather hose .
I have a 1999 xk8 4.0 convertable with 135 k , jusr bought it last month .
PO had work done and bypassed the OEM breather hose with water hose and a fuel line hose inside of it ... smh

rough idle .. and rich gas mix the hose is collasping near the antifreeze resevior

 

Hi,
There's no separate part # for the connectors, AFAIK. PLB hose complete is AJ84880

 

i think i may have found one on Barret SnG .. it looks the part , no pun intended .
24 US dollars .
I already purchased the breather hose OEM . After reading this thread , I can see that this little bypass has created alot of issues .. oil leaks probably comming from Valve cover Gaskets .,
Rough idle air / fuel mix problems ect

 

Curious - did you mean the part that's bonded into the cam cover where the PLB hose connects to?

 

No... the bonded part is still in place its the hose connector that reduces to hose fitting breather hose assembly i have seen in pictures some have a three way with a bib comming out sideways ...that maybe later modal year as in 2000 +

 

The part # is the same for all the 4.0L N/A cars - it does tee off to the throttle body.

 

If this is the part load breather where is the full load breather?

 

It's the fatter one on the RHS cam cover

 

So the one on the RH cover with the corrugated pipe is the full load breather...now I am not sure about the low breather ...??
Why do we need two ...any hole that lets the fumes out is good ????

 

There are countless complex systems & items on these cars that could’ve been make more simple and basic.

But then we’d have a Yugo, not a Jaguar.

Z

 

Thanks, Z but that doesn't tell me where the part load breather is .....are you a politician, never answer a question? Joke ..laugh..its new PM time in the UK

 

read the TSB referenced in post #2.


It’s located on on front end of the left hand cam cover. If you don’t have the special tool, and who does, you can gently insert a small screwdriver onto each side of the low speed breather ( where the special tool’s “arms” would go, spread the ring outward, and with all the delicacy you can muster pull upward. It should release. Beware: As pointed out : The plastic is brittle and breaks easily.

But mine came off fairly easily. There are 2 o-rings right there. If you’s is like mine, the o-rings will crumble off and replacing them is all that’s needed. But if you have the neee to clean it, follow the TSB directions and as
pointed out in a previous post, don’t drop the drill bit.

Z

 

LH ok I will check that one out.

 

To some extent, the clue is in the name:- it's related to manifold pressure (or lack of when approaching WOT).

I've pinched this from Max_Torque on Pistonheads as he explains rather better than I could. Reproduced rather than linked as the site doesn't support a direct link to a post:

"
Understand the 2 system breathing concept:
A "part load" breather uses manifold vacuum, that is metered by a PCV valve (that is a sprung variable orifice) to suck blowby gases out from the CC. The PCV valve controls the maximum negative pressure in the CC by sliding to a smaller opening area as the delta pressure across it increases. Effectively finding a balance point where the flow rate is balanced by the pressure drop of the valve.
This "part load" breather however cannot provide CC scavenging during wide open throttle (WOT) operation (or even during the high part loads on forced induction cars, which require a one way valve or special PCV that incorporates one)

For this reason the "full load" breather system uses the intake depression caused by the intake air filtration system at high mass flows to take over from the part load system as the manifold vaccum decreases towards WOT. (vents BB gas to clean air duct after airfilter and before throttle)

Additionally, to ensure sufficent mass flow for the centrifugal separator to work, a lot of modern cars have a "make up air" breather system, where a large constant pressure diaphram valve opens a pipe between the clean air intake tract and the crankcase to maintain a controlled negative pressure.
Generally this makeup air pressure control valve is using the full load breather pipework in reverse when operating (pulling make up air from the clean air duct)

So to design a successful breathing system you must consider both the removal of the entrained oil, and how your system will maintain the correct massflow and pressure during all zones of engine operation

(or alternatively, just push a bit of hose pipe into a hole on your rocker cover, and stick the end into an old 5litre plastic oil bottle with a few holes drilled in it........
"

Quite sophisticated. My MG has a short hose from a vent on the block to the inlet manifold. My old Anglia had a vented metal oil filler cap, stuffed with gauze, on the rocker cover.

How things change...