98 4Runner Valve Cover and Cam plug maintenance

[Bob98SR5]

Gents,

This is not a write up per se. There's plenty of them, but you might find some value in future posts and dialog.

So starting a new thread here. This is a new thread based on another thread which I created to talk about a possible rear main seal. Doing some homework, sometimes a leaky cam seal plug or valve cover (rear side near firewall) is often confused for a rear main seal. Having done this valve cover replacement in 2016 along with a whole new set of spark plugs and two injectors, I thought I was set. But upon looking at the rear of the valve covers especially on the passenger side, there was a leak for sure but the severity is still "to be determined".

So pulling apart the valve covers is actually not that difficult. But prep and a way to organize the many bolts and a few nut you have to remove is invaluable. As I discovered unbolting mine tonight, I realize that I forgot to secure one of the valve cover bolts on the driver's side from the 2016 job. If you have a Harbor Freight nearby, buy one of those parts organizers. I dropped the bolts in there based on where I removed them and a slip of paper w/ a note to make sure I don't forget where they came from.

Most of the job is unbolting things to get to the valve cover. A good practice is to take photos of everything you remove. Pointing to the removal items definitely help.

So cutting to the chase, I decided a good stopping point tonight would be to remove the valve covers and inspect the rears. The first thing I noticed that one of the valve cover bolts was missing. Also the valve cover bolts were unusually loose in some places. Could that have been it? What I found was that the rears were both a both dirty and wet near the bottoms. What I don't remember doing is if I did the cam plugs or not. I believe this needs to be looked at and I definitely will look in the manual as well as Mike's cam plug writeup I just found here: http://www.ultimateyota.com/showthre...lugs-and-seals

So far, though I didn't look too carefully is if there is any evidence of a poor seal due to my own doing. The gasket was seated really well (took some effort). Perhaps the valve cover bolts weren't seated properly? Some of them turned way too easy for my liking.

On another note, those are rubber plugs I bought at Ace Hardware to seal off the spark plug holes (#3). And no cause for alarm for the green oil. That's the leak detection dye I used to trace the leaks. It did a much better job for the power steering lines than the oil issue.

[4x4mike]

As you know, leaky valve covers are common on the 3.4's. The valve cover fastener torque is not very high and the factory washer/grommet/isolator compresses and hardends over time leaving the fastener loose. I don't think the fasteners loosen as much as the tension from the washer/grommet/isolator lowers over time.

I'm in the "if some is good, more is better" boat and give them a little more and follow up on oil changes. You have to be careful though because the valve cover can break very easily. I've known a few guys that have broken one, or more, and they said it didn't take much. Since you have the valve covers off I'd replace the washer/grommet/isolator thingies as well as the spark plug tube gaskets if you didn't do them in 2016. Again be careful with the valve covers especially if you do the tube gaskets.

New washer/grommet/isolators will be taller than your used ones and you'll see how they compress. My old ones were fine but very hard and squished pretty good. After installing them I checked their tightness a could of times for the two following weeks. Once you get everything bolted to the engine some are hard to access but it's worth it to get to them in order to ensure proper sealing.

[Bob98SR5]

I'm in the "if some is good, more is better" boat and give them a little more and follow up on oil changes. You have to be careful though because the valve cover can break very easily. I've known a few guys that have broken one, or more, and they said it didn't take much. Since you have the valve covers off I'd replace the washer/grommet/isolator thingies as wel .

Yup plan on replacing the bolt washers and the plug grommet things with the valve cover gaskets. Good advice on not over doing it.

By chance do you have a pic where you applied the FIPG on the cam plugs?

[4x4mike]

No pics but it was in the corners. I know, corners on a circle. Basically a dab where the circle met the valve cover mating surface. I believe I spread a thin layer on the plug as well.

[Bob98SR5]

Oh ok, thanks Mike. I just found a good writeup over at T4R where he shows where to put FIPG. But I think he went a bit overboard vs. what's shown on the FSM pic he also posted.

Today I think I'll have just enough time to soak the valve cover in a bucket w/ some cleaner as well as removing the half moons, the cam cover, and cam plugs.

[Bob98SR5]

Ok cam covers off, cam plugs out, and half moons out as well.

Hardest part was removing the half moons. I had to use channel locks opened by 2 notches and held at an awkward angle. Unfortunately I marred up the half moons in some sections to where the aluminum is grooved a little, which caused some spikes near the top of the half moons (the flat side, not the rounded side). I'll need to carefully sand down the little peaks as they're on the flat part where the gasket will sit. The best advice I have if you've never done this is to wiggle it slightly w/ a tool to break the FIPG bond. Then pull it up with a little force and it should come off. There's definitely some resistance, but once you feel it going, it's released its seal.

Upon closer inspection of the areas where the FSM says to add FIPG, I can see I had added little to no FIPG where the FSM said to add it. In fact, I didn't even remove the half moons and didn't add FIPG where the half moons meet the bottom of the valve cover gasket nor the shoulders where the cam covers seal the cam plugs (on the outer side). See the diagrams I shot from my FSM. To make it obvious for others, I've red highlighted those spots.

So in short, despite having the FSM, I either completely forgot to do this, neglected to do this, or was smoking crack when I did the valve cover job in 2016. Or all of the above.

Tomorrow's tasks:

- clean off rear area so I can see if I seated the cam plugs and half moons well or not
- Clean the engine bay a little while things are off
- Clean off valve covers
- Wait for Conicelli Toyota to send the cam plugs

[YotaFun]

Bob,

I just redid the valve cover gaskets on my stepfathers 02 4Runner, I last did them about 50k ago and they started to leak horribly again.
Like Mike had mentioned the rubber begins to get hard and shrink causing the bolts to begin to come loose, I was able to remove each bolt by hand.
And a mike mentioned, factory service manual states tightness at I believe 18 in lb. which is not much at all. I feel they should be gone over after another 10k, but pulling the intake makes that task not so fun...

I do my bests to remember to add the FIPG when I do those gaskets, I think I forgot to do that when I did the silver 4Runner valve covers and will need to go back and do those soon.

[Bob98SR5]

Avi,

Thanks for the reply. I am 100% sure I didn't remove the rear half moons or FIPG them, and that might've contributed to the leakage. Though Mike4x4 says not to FIPG the circular cam plugs, I am oh so tempted to put a very thin layer on them. But probably won't as the manual doesn't say to do it.

[Bob98SR5]

I didn't do the half moons or replace the cam plugs. My tube of FIPG was untouched. Why the heck didn't I do it? SMH.

Anyways my stupidity made me do this unnecessarily one more time. Nothing really to write about other than to make sure to apply the FIPG as I circled in the pics above. The half moons was easy enough to just squirt right down the middle and set them in place. As for the FIPG near the cam plugs, make sure to squeeze some FIPG where the round rubber side intersects with the bottom half of the valve cover.

Oh and don't wait too long to seat and bolt down the valve covers.

[Bob98SR5]

Ok guys I have two extra sets of OEM cam plugs so if anyone would like to buy a set, contact me and I'll work something out cheaper (total price shipped) than buying from the dealership.