Hey there all!
Sorry it's been a while but have been very busy... divorces will do that for you :redface:

I have been having continuous oil leaking problems and need a bit of advice.

I had just fixed everything up in my engine bay after oil leaks from filler cap as I found a faulty PCV, knackered cap seal and deposits clogging up the rocker cover openings etc... all fixed and looking great. All of a sudden oil was pi$$ing out every where again but this time I couldn't find the source. Took it into the mechs and finished up replacing a lot of the engine seals around the timing chain cover area which meant a lot of strip down to fix (and replaced timing chain too).

Ok... Zap thinks everything is ok and then again... oil is leaking from the oil filler cap! I just replaced the PCV so this should be ok... I find that when the motor is running there is a pressure build-up so when I open the cap it makes a hiss. I know there is no blockage in the hose to the PCV as I can feel air coming out and when I put my finger over the PCV it clicks as it should. However as soon as I put the hose back onto the PCV it builds up pressure again!!

HELP! :cry:

How many KM on the clock? Compression test is the best way to assess the mechanical condition of the pistons, rings, valves etc...
You said that there is pressure build up when engine is running so this was first thing that crossed my mind. Worn or broken piston rings or excessive wear in the cylinders, pistons and rings.
Do you need to top up oil between oil changes? How much?

Goddam Crappy 12 valvers!
Its still happeneing to me too :(
Replaced just about every seal on the engine (and cap) and its still leaking from the oil cap + other places, are these engines supposed to leak oil from factory? im sure they are as every one is

Thanks guys...
The car has done a little over 230K and the only engine issue I have is the valve stem seals are on their way out (but having said that is hasn't degraded any further for about 5 years now!!) Up until these issues I have never had an oil leak (Sorry TUFFTR :D)

HOWEVER>>> I think I have found the solution...

When I had my initial problems with the sticky PCV I replaced the hose from the Rocker Cover with a standard style hose from S-Cheap. It looks to me as though it isn't very heat resistant and has not made a complete seal around the PCV. I just put a hose clamp around it and now the pressure is not building up. I am wondering if there just wasn't enough back pressure to allow the pcv to open, but enough pressure to leak oil from the cap!!!

HA HAAAAAAAA!!!

Don't use radiator hose for anything relating to oil on the engine. Ensure that if you replace the PCV line hoses, that it is with a hose that can handle some vacuum once it heats up. It may seem OK while cold, but I have had issues with my Magna where the hose would collapse due to vacuum and cause pressure to build up inside the rocker cover. I got oil leaks everywhere too - even stuffed the front end seal and blew the dipstick out of the pipe sometimes if I drove it hard (more than once I found the dipstick hanging out against the radiator lol)!

Best pipe to use is fuel injection hose, as it is very thick (thus doesn't collapse under vacuum) and it is resistant to oil. It also tends to form a nice tight seal around any connections, so you may not even require hose clamps. It may be more expensive, but it is definitely worth it!

I have read through all of these posts about the filler cap. They all mention the pcv valve on the front rocker cover but no one mentions the rear rocker cover breather valve(on a V6). I did the same thing, cleaned out the pcv valve and breather valve at the front but to no avail. I found my problem was on the rear breather valve. here is a hose that runs from the emission contraol to this but the actual breather valve on the back was so clogged that the screwdriver i was using to clean it out wouldn't go through. I slowely put a little metho in there and finally unclogged it (this may not be the best thing to put in your engine but it was the easiest way to clear it).

Lo and behold no more oil leaks! lol

It is a fairly common problem with carbon deposits clogging the small pipes but with regular maintenance of these parts the engine should be fine with no leaks.