az_eaglescout_pilot

iTrader: (1)

I have had the leaky valve cover problem on my 3.0 and have tried 4 times to fix the problem. This time I noticed that the covers were slightly bent out on the ends. Pretty sure this the reason they are leaking but i want to make sure that they arent supposed to bent. below are pictures of the covers.

rustyf99

iTrader: (1)

I can't open the pix but I am pretty sure they should be completely flat on all the flanges, except where it goes over the cam seals of course. I have extra pair in my shed, if you want them PM me and make an offer.

az_eaglescout_pilot

iTrader: (1)

they are flat on the surfaces that touch the heads but the ends are flared out that is what i mean by bent. could you post a couple of pictures showing the bottom of the covers?

rustyf99

iTrader: (1)

They are supposed to be that way, yes they flare out a bit at both ends.

scope103

Installation of the valve covers calls for RTV at certain spots (where it makes a sharp corner over the cam bearing). I found that RTV does not adhere well to the head unless the head is absolutely clean. Any oil film will cause the RTV seal to leak.

So get some paint thinner and thin rags, and work carefully. That might be all you need.

250000_yota

Are you using any silicone on them or are you just placing the gaskets on dry?

I know it's a stupid question but I hate hearing that you've had to pull your plenum 4 times just to try and fix this...

az_eaglescout_pilot

iTrader: (1)

Everytime I have done this there has been loads of RTV. I clean the mating surface extremely well with rags and carb and choke cleaner, let it dry. the gasket is RTVed to the valve cover before hand, then I put a nice heavy bead of RTV all the way around the gasket (especially on the lower edge and corners) and set it on the head, line it up by putting all the bolts in and just barely tighten it until the RTV shows movement, let it sit for a full 24 hours then torque the bolts...it will hold for a month or two then starts leaking. I used Gray RTV for all the previous trys. this time I am going to use ultra black. Look on the bright side...I can pull that plenum off in no time at all! haha pretty much know which vacuum line goes where too even without my diagram and numbered lines!

Out of curiosity why are they flared out at the ends?

Kiroshu

Its best to do as FSMs says, if the Valve covers on the 3.0 aren't excatly tourqed and sealed correctly they will leak.

Use the OEM gasket(s) and RTV the OEM Spots Recommended by Toyota and tourqe exactly to spec and you should be fine....

Ive never seen luck with ppl using RTV all around the entire cover.... they tend to come back leaking...

Its slightly possible the covers could be warped... as they are mainly plastic... >_<

rustyf99

iTrader: (1)

Sounds to me like this is an issue of "too much" instead of too little. The factory seals work very well with only tiny dabs of silicone at the sharp corners. A spot or two of silicone in the groove to hold the gasket would be OK too, but I think you are using way too much and getting an inconsistent seal strength around the perimeter. Then the oil starts leaking at the weak spots.

az_eaglescout_pilot

iTrader: (1)

hmm interesting i'll give it a shot.

rworegon

Sometimes less is better....too much FIPG/RTV interferes with getting the proper torque, IMO, especially at low torque values. As said above, clean well and apply it as the FSM specifies.

Can't remember.....does this head have the 1/2 moon plugs in the head? If so, those may need to be popped out, cleaned, and FIPG/RTVd back in position.

Or, the camshaft housing plug may be leaking.

az_eaglescout_pilot

iTrader: (1)

Mine does not have the plugs you speak of...thankfully. Im pretty confident that the cam plugs are not leaking because of the pattern the oil has traced but since it is all apart wont hurt to double check