October 29, 2006
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CSI: Vanagon
This is the inside of a leaky valve cover for a 1987 Volkswagen Vanagon (2.1l 4cyl):
Why is it leaking? Well, at first glance, we see this gap where the gasket hasn’t been making a very good seal:
Seems pretty obvious. But wait… That’s not where the oil has been leaking out. It’s been leaking out at the bottom. Right here:
See the bulge on the right? Let’s clean it out:
From this angle the deformation doesn’t look that severe, but it’s a bit worse than it looks. Nothing to make you give thanks to the gods that keep your van together despite its problems, though. The varnish chipped off during cleaning, obviously, which isn’t a good sign.
How does something like this happen? My best guess is that pressure built up in the engine when the catalytic converter plugged itself up. It doesn’t seem like there’d be enough pressure to dent a valve cover, but this specific leak (as opposed to the *other ones.* Har!) developed right after the catalyic converter problems. It could also be a clogged oil pathway in the engine, which we really really hope it isn’t. Or someone could have dropped it in the 19 years I *didn’t* own the vehicle.
I replaced both valve cover gaskets with new ones, so I’ll drive it a little while and see if the leak is fixed. If the leak is stopped, then the only reason I’d need to get a new cover is for my own peace of mind.
Comments (6)
an education…
Car Systems Investigator?
Old Fords are known for valve cover leaks. People tighten down the valve covers too tight and make indentations around the screws (so they don’t bring the cover clear down) and/or warp the flanges, causing leaks. Then the heads of the screws hide the indentations. So when a leak appears, they tighten it down more. I wish I could draw a picture.
It’s good to make sure the flanges are straight and don’t have bumps and bends. If so, you can straighten them out, if it’s sheet metal. The gasket shouldn’t need to be compressed tightly. There may be torque specs for the valve cover. I don’t think you would need a new one.
And maybe lay a straight-edge across the surface of the head where the gasket makes contact.
Since the gasket seemed to shift during installation for the last guy, It’d be good to glue it lightly in place next time.
I dont think crankcase pressure would have bent it. But blowby might have forced the leak.
People really do need to take a close look before they just stick in another gasket.
The valve covers clamp on with a big metal spring, so no chance to over-tighten. I checked to see if the cover was flat where it meets the gasket, and it was. I didn’t want to bend the dent back, because it looked like it might break off.
We’ll see if the leak persists. You’re probably right about the pressure forcing the leak, but not the dent.
If I were at all a badass mechanic, I would have completely cleaned out the inside of the cover, and maybe even repainted outside.
you’re a more badasser mechanic than I. I get really nervous when I take stuff apart on my car (or worse, my wife’s) because I never know if it’s going to work when I’m finished. Which is ironic, because I used to tear apart and rebuild gazillion-dollar pumps and nuclear reactors and whatnot when I was in the navy and it didn’t bug me then..
Is that ironic? I never know if I’m using that word correctly.
My old car had a bad vc gasket– I thought hey, a gasket, I can probably replace that myself. Sadly, it was a tiny economy car, and when I looked it up in the how-to book, it turned out you’d have to *remove the engine* in order to replace that one gasket. Which would have cost more than the car…