[size=+2]Valve Cover Gasket Replacement
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Last weekend, I decided to tackle the leaky valve covers. I was not able to stop them from leaking by just tightening the bolts. I was quoted at a couple of places between 450-525 to replace the gaskets. The replacement isn't difficult, just tedious. I also was curious to see the valvetrain after ~195k. I have been through about 10 oil changes since I got it and wanted to check for buildup or other sludge. The parts collectively were about $100, sourced online. The major part of replacing the gaskets are labor. I ordered the following parts from Toyota:
1213-62020 Valve Cover Gasket (2)
90210-05007 - Washer Seals (16)
11188-62010 - Camshaft Plugs (2)
11193-70010 Spark Plug Gasket (6)
PNPTR2960030 - TRD Throttle Body Gasket
17176-62040 PCV Grommet
12204-62010 PCV Valve
90979-01192 Spark Plug (6)
19037-62010 Spark Plug Wires (1)
Throttle Body Cleaner
Black Gasket in a tube
Acetone
Couple of cans of brake cleaner (always on stand by)
The operation was pretty straightforward. To save time and frustration, I labeled every vacuum hose, electrical connection and took a pic of the label so I wouldn't forget. There are about 15 of them and keeping them in order was a huge concern while doing this. Once marked, start at the airbox and work backwards, disassembling each piece.
I knew from the outset that my PCV was malfunctioning - it was pretty obvious just looking at the passenger side valve cover.
Once you get to the throttle body, you might as well clean it. This one wasn't as bad as I have seen in the past. Remember to plug the coolant hoses after removing them. I stuck a couple of 12mm bolts in there and clamped them and they were fine.
Not horrible but could be cleaned up a bit
The intake had a nice oily sheen to it, again due to the failed PCV valve and broken grommet. A can of brake cleaner later and it was clean again. Once both the upper and lower manifolds are removed, put tape over the holes in the valley pan to keep stuff from falling in there.
Finally got to the money shot. My harness was cracked badly on both sides - the result of heat cycling. After moving it as carefully as I could, I still ended up with small bits of plastic in the valve-train I spent a good 30 minutes making sure it was spotless before the valve cover went back on. I was impressed with the color and the lack of sludge. The half moons and camshaft seals at the back of the head were leaking badly. I gently removed them, cleaned them up (you can never use enough acetone) and added a very thick bead of Black Gasket in a Tube and stuck them back in. Be generous with the stuff - too little and they will start leaking again. Once both half moons were gasketed in place, you have about two minutes to get the cover back on. I started tightening the bolts, inside first working out in a star pattern (like tightening lug nuts) and torqued them all first of 40 in/lbs, then to the recommended 52 using the same pattern.
Passenger side vavletrain
The driver side was pretty similar. No sludge. Some plastic bits did fall in the head so it was cleaned spotless before the valve cover was replaced. The half-moons were dealt with in the same manner as the passenger side.
Upon reassembly I cleaned up the throttle body. A soft bristle brush and some throttle body cleaner made it good as new. When I replaced the throttle body, I used the TRD gasket. This gasket is included with the supercharger and is perfectly round. The factory gasket has more of a "D" shape to it. I don't know if it impedes enough air to make a difference, but for $7 it is the same price as the factory gasket so replacing was easy. TRD says the gasket it is good for 7-8hp in a supercharged application so it maybe 1-2 in an NA application. I also replaced the PCV grommet and PCV valve - no more blowback!
Factory on the ride, TRD on the left. Note the perfect circle that the TRD gasket has compared to the factory gasket.
Once all buttoned up, I changed the plugs and wires. Plugs looked clean and didn't show any moisture or oil. Thanks to marking the lines and connectors everything went back together just fine. A couple of lines had hardened. I used silicon spray to soften them and put them back. My garage is unheated and it was about 50 degrees when I did this. I used my heat gun to warm up the hoses prior to putting them on their respective nipples. Truck started up fine and didn't throw a single code. I spent about 5 hours over two days replacing these - about on par with what a shop would take.
Money saving - Doing this again, I would have done a couple of things different. I purchased sparkplug tube gaskets and they didn't need to be replacing A quick search of the tubes revealed that most peoples tubes never leak. I skipped replacing them on mine. The manifold gaskets are reusable. There seems to be a debate about this in some of the threads I researched. Be gentle and they will be fine.
Also of note - Before diving into this, I picked up the ISR mod from ALBPM. He helped develop this back in 2002 and ran this for a while before upgrading to another intake. I painted it flat black, baked it, cleared it, baked it and installed it. It does make the engine louder; the engine does seem to be more responsive. Running 286/75/16s (see next post) with new plugs, wires, the deckplate mod, ISR and a clean airfilter has netted me 18-19.5 mpg with my 4.10 gears. Long term will be interesting.