Valve Cover Gaskets

04/07/2023

I’d been noticing a few oil spots showing up in the driveway lately, and after hitting the engine bay with a UV light, I could tell the leak was coming from the top end. My first guess? Valve cover gaskets. The bolts looked tired, the gaskets were probably ancient, and it seemed like the right time to dive into what turned out to be a very long weekend of wrenching.

Since the valve covers are buried under what feels like half the engine, I figured I might as well replace everything I could while I was in there. Good thing I did—because whoever last worked on this thing left behind a mess worthy of its own horror movie.

The first “oh great” moment came as soon as I pulled the intake. Three ignition coils, all different brands. Somehow I never noticed that before. Only one was OEM, which I’m guessing is original to the truck, so the other two just made their way to the “replace later” list. Then I pulled the upper plenum and saw a nice shiny surprise—cheap aftermarket gaskets. Perfect.

Once I got down to the valve covers, the real fun began. The plastics were brittle enough to crumble in my hands—loom covers, clips, electrical connectors—you name it. I broke a few despite being careful, and after dropping more than one bolt into the abyss, I ended up pulling the skid plate just to retrieve them (note to self: start with that next time).

When the covers finally came off, I was greeted by what looked like an RTV art project. Someone had gone way overboard—there was sealant on everything, even the spark plug tube seals. Those were so brittle they basically disintegrated when I tried to remove them. I spent a good while cleaning out debris, blowing out the plug wells with compressed air, and brushing everything down until it looked halfway decent again.

From there, I replaced the seals and gaskets, installed new half-moons and cam seals with Toyota FIPG, and moved on to the passenger side—which was just as bad, if not worse. Once both covers were buttoned up, I swapped the plugs and wires, gave the throttle body a good cleaning, and started reassembling everything with the proper OEM gaskets.

Moment of truth: turned the key, and she fired right up. No smoke, no drips, no weird smells. Took it for a quick spin and everything sounded and felt solid. I’m keeping the skid plate off for a few days to check for leaks, but so far…bone dry.

Fingers crossed—it looks like the 4Runner lives to fight another day.

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