I finally got around to this little task today. My Delica developed a very small oil leak right after I bought it, which was odd because the previous owner had just had the 100,000km maintenance done, and the engine was spotless.
So this took me 5 hours, mostly because, "Double check the top of the head that it's clean and there are not pieces for dried up gasket stuck to it." I'm not sure if it was old gasket (the one I took out was intact, so maybe residue from a previous gasket) or Permatex Black, but I had to scrub little bits of it for a couple of hours to get it clean to my satisfaction (those who know me, feel free to chuckle at this point.)
My tool of choice for this cleanup, better than brass brushes, Scotchbrite, or jamming rags in the groove was this:
- TongueDepressor.JPG (116.41 KiB) Viewed 7813 times
It's a tongue depressor, cut at 90 degrees to get rid of the rounded end, then split into 5 pieces, and tape wrapped around to keep it from splitting any further. I scrubbed back and forth in the groove, like a broom, and because of the splits it would curve around corners, especially useful on the glow plugs side where nothing's a straight line. It rubbed the debris into little, snake-like goobers, that I whisked out with a toothbrush.
Also worth mentioning, another invaluable tool for this job was one of those swivelling mirrors on a telescoping rod. Very handy for checking out the half moon seal, whether you got the surface clean enough, etc.
I read somewhere, to get the half moon seal out you just reach back there and pop it out with your fingers. I had to get small vice grips on it, and you can see there was quite a bit of goop holding it in place. See the importance of applying only a small bead of Permatex Black when reinstalling.
- RubberMoon.JPG (110.58 KiB) Viewed 7813 times
Also note, I replaced the rubber half moon with an aluminum one, from Harold Zeigler Mitsubishi, Kalamazoo Michigan, Part#MD372348. When this thing arrived, I thought it can't possibly be the right one, it's too small, but it fit perfectly.
Oh, and a Deli mechanic told me there's another one in the front too, but it's harder to replace. I found it hard to replace because it doesn't exist! I looked for it, but didn't find it. So I've got a spare aluminum half moon gasket, all the way from Kalamazoo. PM me if you're interested.
Can someone explain the half moon phenomenon? I mean, why not just make the surface flat all the way around? Is it because they need the half moon cut-out to get the cam shaft in? I'm sure it's necessary, just inquiring minds want to know.
And the other mystery, when I ordered my gasket, it came with two rubber seals, which I installed around the bolts that go through the head cover...and it also came with two more, similar seals (these ones with metal cups on the back) which I didn't use because they're for larger bolts than the ones in my engine. Anybody know about this? Are there Deli engines with valve cover bolts larger than the ones with 12mm heads on my engine?
- LargerLeftovers.JPG (45.56 KiB) Viewed 7813 times
Got a couple of leftover rubber seals. PM me if you need some for your larger bolts. ;)
As I was putting the timing belt cover on, the foam seal from the top edge fell out. So I pulled off the cover and looked around for something to replace it...and noticed the old valve cover gasket was about the right size...so I cut a couple of pieces to length...but they were too tall...so I sliced them lengthwise with a knife...then put them in the timing belt cover with a bit of Permatex Black in the groove... (I'm just sayin')
Oh, and I don't have a torque wrench, so I just imagined I did, and 4-5lbs would be way down at the light end. Then I couldn't get the timing belt cover to seat unless I tightened down the front some more. So I torqued it just until it fit, then pulled on the back bolt about the same. Probably around 7-10lbs, I reckon. Or maybe when the timing belt cover just fits over the valve cover, that's 4lbs spot-on, and so you don't really need a torque wrench. Food for thought.
And furthermore (this just keeps getting better) I was wondering why it leaked in the first place. The speculation was that the rubber half-moon had given way (hence the aluminum bits from Kalamazoo) but there didn't seem to be much oil down the back. Most of it was on the exhaust side of the engine (which is why my passengers asked, "what's that smell?" going up a steep hill), below the straight edge of the valve cover. I inspected the groove, and it was rough in patches through the middle. Pits, caused by the beginnings of oxidation. I wrapped some sandpaper around My Favourite Tool and gently sanded the pits smooth. Then finished up with some Scotchbrite. So I think that's why it was such a slow leak (1/4 litre in 15,000km): the oil was going up over the gasket, through the tiny pits created by oxidation. And that's why it wasn't getting worse, because the oil kept the oxygen out, keeping oxidation to a minimum.
So I'm hoping that with a smooth groove and a new gasket (and an aluminum half moon from Kalamazoo!) there will be no more leaking.
And after I degrease the engine, no peculiar smell. (sigh)