Changing the valve stem seals solved the oil consumption problem in mine. That was what drew me to this thread - excessive oil consumption. I was using half a litre a week driving around town.
I guess I was losing a bit of oil up the intake pipe before I drilled out the PCV valve, but it was nothing by comparison to what I was losing through the seals.
The Ford Motocraft Semi-Synthetic I am using, which is the cheapest oil here, was not to blame. I am not losing a drop now the valve stem seals have been changed, despite the motor having done 231 000 now. And the Americans swear by this oil. It does not have a poor reputation. It is recommended in my mate's Explorer manual.
The problem became evident when I pulled out the old valve stem seals.
The valve stem seals were not degraded. That oil scale grit builds up between the valve stem and the seal there, and they just no longer seal. It does not wash away with oil changes in the top of the head either, although regular oil changes removed every trace of it in the bottom of my motor. If you got the problem, you have to change the seals. Just cleaning them would have worked well even, I reckon, cause mine were still plenty supple.
However, although it was not at the heart of the oil consumption, I am so glad I drilled out the PCV valve and put the catch can in.
Although I cleaned it very well 40 000 km ago, the top of the motor was full of that grit again.
It was all over the timing gears and had filled the grottos behind the timing cover as well. It was blocking the oil galleries. Might even have just been a chunky bit of it caused that scoring there when it popped out, cause it gets hard as a rock.
Only parts of the motor that were clean were those constantly actually immersed in oil down the bottom end. Anything just washed with oil flow from the pump was filthy.
It is not surprising this came to be when I look at what is collecting in the oil catch can. My engine is fully clean throughout now, and this is what I am getting.
There is the very watery liquid, which soaks into a tissue, and the beginnings of sludge, which won't. It totally looks like congealing gravy at the bottom of the can. You have to scrape it out, it is not tipping out.
I am getting grit as well. It isn't just residue left over from cleaning. It comes from the breather port over which the PCV valve is located, which is sealed off from the remainder of the right bank. Sometimes it is chunky pieces, too, you wouldn't even imagine could fit through a drilled out valve.
And this is going in the top of your motor, to be washed down into the sump and then recirculated all the time! There is a lot, too, my catch can needs emptying frequently. Oil level isn't dropping at all, this stuff in the catch can is mostly juicy extras from combustion.
So yeah, the enlargement of the PCV valve and the catch can is the best thing ever if you want your motor to last and be happy.
All that crap is wrecking the seals, restricting oil flow, scoring moving parts, and probably adding extra wear to and unbalancing them because the sludging can grow to coral reef proportions if left unattended.
After cleaning it, and changing the valve stem seals and having full oil flow through a clean pick up and galleries and across the places where coral once abounded, my old engine is not using a drop of oil. It has a new life, hopefully for a long time to come.
All my neighbours who saw me struggling in the parking lot kept saying to me 'buy a new car', but with just a catch can, an oil pick up seal and some valve stem seals, I have a car I reckon is pretty much as good as new. Much better than whatever shitty second hand car I would have been able to afford as a replacement, anyway, cause at least I know everything is in good order, having investigated the workings of everything and put all things to right.
