Valve cover gasket replacement 3.4 V6 tips

There is a FULL moon seal under the rear most cam cap that leaks also. Had to go back in on mine to do that one. Some people just by new moons as they come with silicone seals already on them but grey RTV works fine there too.

 

Would like to confirm that the full moon cam seals are replaceable on the AFT end of the head only, in other words 2 are needed for a full job. I can't tell by looking at the front if they are replaceable or not and my Chilton Manual doesn't reference itll

 

Just finished measuring all my valve clearances and they are all within the spec range: intake .006-.009", exhaust .010-.014". Nice, that saved some work! Of course this is only one data point, YMMV.

 

Just rear. Cam seal on front where it exits to cam pulley.

 

Aha, of course. Thanks.

 

my dealer charged me two hours to do this . with parts it was 270.00

 

It's so you may use the head for either side.

 

In the middle of the replacement and in regards to those full moon cam plugs I thought that I had read somewhere that the concave side faces out the back but when I pulled them the old one had the concave side facing in. Does anyone know which the the proper install?

 

In case anyone's searching through this thread and wants a walk through:

 

Watch it last night and got my answer. Thanks D.

 

I am going to do a whole pile of maintenance next spring in the engine bay. I have been buying time by torquing the 8 lower bolts on the valve covers that can be reached. I can reach all eight now with a small swivel to help with the one in the rear on the driver's side. I recently had oil leaking again onto the exhaust manifold which was worst on the drivers side rear. I was really starting to get concerned about burning her up. Anyway, I torqued the lower 8 bolts to 45 INCH pounds this time and, once again, no more oil leaking onto the manifold. If you need to slow it down until you can get to it I recommend trying this approach. It's worked for me twice now. It's at 210,000 miles.

 

My tips for this job:

If you feel like you're fighting to remove the valve cover or it's too tight (as a couple videos show), you haven't disconnected enough cables. I was missing one on the driver's side dash and once I unclipped that, it was quite easy to remove and install the valve cover.

Clean very well everything above the valve cover. Anything above is liable to fall into the engine as you pull the cover out. Tape up the plastic wire protector above the cover in case it breaks. I used metal tape and regret it as it was very difficult to remove (so difficult I left most of it on there). Maybe blue painter's tape would be suitable given the temporary nature.

The spark plug seals seem obvious to me which way they go, but pay attention to the old ones before you remove them. The factory service manual doesn't specify the orientation. The factory service manual does specify the cam plug orientation (concave side facing inwards).

I used new upper and lower plenum gaskets, new throttle body gasket, new valve cover gasket, new valve cover bolt gaskets, new sparkplug tube seals, new sparkplugs, new wires, new cam seals, reused half moons (if they're cheap I'd buy new as cleaning them (with hand tools) is painful. I cleaned my MAF and the throttle body and IAF. I reused the old IAF rubber gasket. I also replaced my air filter while tuning everything else up, it did need it.

Take pictures of the things you disconnect. Sort bolts in ways that make sense. When possible, put removed bolts back in their holes. Try to keep hoses and cables aside/out of the way. The FSM actually is helpful, unlike what some people have written. That said, it could be more helpful.

While I was in there, I noticed one sheared bolt and two snapped plastic pieces (someone had ripped the plastic wiring harness off the passenger side valve cover instead of unbolting it. This must have been done by a mechanic used by the previous owner. Makes me feel accomplished to have performed the job with fewer mistakes than a professional (although I certainly took a hell of a lot longer).

 

Did mine last month, just take your time, not that hard of a job.
If your wiring harness is falling apart or broken (plastic heat shield) use some heat
resistant (300 degrees) Tesa Tape and Napa wire loom brackets.

I also replaced the heater core hoses and heater valve since I was in there.

Those valve cover bolts washers end up shrinking over time from heat and that’s why tightening them
up sometimes will solve the leak.

 

I forgot one other potential tip. I used high temp, medium strength thread locker (NOT red loctite, it’s a higher temp version of blue) on the valve cover bolts.

 

ok but that's not an upgrade. The seals shrink, not the bolts coming loose.

edit: Look above at pictures from 1997TacomaV6 posts.

 

Well, idk if it’s good or not, but that “shrinking” could simply be the squishing that occurs upon installation. If in doubt listening to the FSM (does not specify loctite) is good. Time will tell. I’ll update here in a decade if it doesn’t leak, or if it does leak I’ll update sooner.

 

It is. Then after getting hot it holds that shape.

Putting on Loctite won't CAUSE a leak.

 

Those bolts are known to come loose overtime, thus the leak.

 

Well I'm kicking myself now because I just put the spark plug tube seals in backwards... I just put the covers back on but didn't put the intake back together yet. I spotted it while watching a youtube video. What are the chances it'll be alright? They still make a tight fit. I can't believe I did that...

 

The side of the seal that you see in this pic...should it be facing toward the engine or toward the hood?