Torque On 3.4 Valve Covers

Getting some seepage from my valve cover gasket, I noticed the bolts are barely finger tight and often loosen up over time. Now I've heard you torque these things down to 53 INCH lbs which is 4.41 FOOT lbs according to the lovely unitconversion.org... and I have also heard that they should be tightened to 13 Foot LBS. Just thought I'd ask before I start wrenching on these things.

 

that's correct. 53 inch lbs. I wouldn't tighten them to 13 ft lbs. that's almost the breaking point of the bolt (when the head just twists right off). but that's for grade 8.8. grade 4.6 has a max torque of about 8 ft lbs. they would twist right off in no time.

 

I just re-torqued my valve cover bolts AGAIN to 53 inch-pounds. At least the ones I could easily access.

I think this is the third time in about 5 years and most were only hand-tight at this point. Leaking oil, of course.

Just confirming...that 53 inch-pound spec is for the V6, correct?

 

yes that is with new everything, crush seals, gasket etc.

 

What do you think about going to 75 inch-pounds, which is halfway between the specification and the max of 8 foot-pounds you mentioned?

53 inch-pounds is obviously not working.

 

I did my VC gaskets 20,000 miles ago and I'm seeing seepage on the drivers side and passenger right side of the cover. Bolts have a loosened up, should I take of the plenum and tighten the bolts or re do everything while I'm there?

 

i have about 23k (maybe 24k) on them so far, i should also check more closely for leaks again, i just give them a glance now and then, a slight finger swipe if not too hot

 

If you replaced the valve cover gaskets 20k miles ago then I would try just snugging up the bolts. If you used good quality gaskets they should easily go 100k miles assuming it was done correctly.
Did you mess with the half moons while you did the gaskets?

 

no, there is a small weep possible recently noticed, headed to get a mechanics mirror to personal inspect what the situation is going on behind there in the back

 

When I first did my valve cover gasket on my 3RZ, I broke 3 of the bolts using an inch-pound torque wrench. After that I decided it was worth it to get new bolts. It's really annoying to get to the last one and have it break. Then you have to remove the whole cover to get the bolt out. I wouldn't push my luck with over torquing them, they are really weak.

 

I use a short 1/4" ratchet and snug them up using only a couple fingers, makes it harder to overtorque them or break the weak bolts.
I always do it by feel, and when they loosen up over time which happens, just snug them back down but after that I wouldn't try and tighten any more to stop a leak, take it off and see what is happening.

 

@cruiserguy I did, I cleaned the half moons and resealed with Toyota's FIPG (black). The driver side rear moon feels moist upon touch

Shortly after doing the job, the driver side started to get seep around the lower bolts especially the rear one, but the passenger side has held up well up until recently. Since I have tightened a few bolts as time has passed while the bolts inaccessible have not been touched(some of bolts being good and some not = uneven pressure), would it be best to remove the plenum and undue all bolts and re tighten in the star configuration to ensure even pressure is applied?

In other threads, I've read not to apply FIPG where the gasket sits, I may have done this thinking it was extra insurance.

 

I like your username dude, it makes it much much more enjoyable discussing these things with folks that understand and appreciate the Toyota way
And I'm assuming you're reasonably versed with the auto repair/maintenance by the way you talk about it. With the additional details of the possible weeping from one of the half moons, and possibly differing tightness on the bolts, etc, I would do as you mention and remove the intake and stuff to get to the covers and redo that half moon if it's leaking. There is a Timmah! the tool man video that is very comprehensive and covers all details pertinent to this repair.
But I do think you were correct in asking about going back into it fully too get the weep or dampness corrected. It'll be quicker the second time around too.
Have you seen that Timmah vid that covers that stuff? I can find a link if you haven't. Or you can find it too, it's on his youtubes channel.
And since the gaskets have a few heat/cool cycles on em by now, make sure to tighten the bolts down in the proper order on those valve covers and I'd also prolly go to the torque spec and may need an inch/lb or two more with some age on them. And I believe there's only FIPG where the half moons are involved.

 

Yeah, cruiserguy is on point. maybe pull the plenum and see if any of the bolts you couldn't reach are loose now. if you find several in the area with the leak, maybe snug them and see.
If you don't find any ones that are loose right in that area, then time to pull the cover and do it again.
If it makes you feel any better the first time I did it on a small block chevy, I went through 2 sets of aftermarket covers and 4 pairs of gaskets, before I found the right cover and gasket combo to stop all the leaks.
Compared to that... the toyota ones are easy

 

@cruiserguy Thanks bud! It was my first time doing the job and satisfying enough to convince me I was capable of changing out the clutch eventually.

I'm familiar with Timmy the Toolman's awesome videos on youtube and will watch it.

@2JHilux- On the same page with both of you, I think I'll go ahead and remove the plenum and re do moons if needed, and re-torque the bolts since it's easy enough not to. That's gotta be frustrating, but I'm sure you enjoyed that vehicle to have done it multiple times.


I noticed this (see attached photo) on the back of the driver side cover, there's an upright 90* covered in oil, the hose attached runs over the plenum to the air box.

 

That is the valve cover breather, fresh air from the intake goes through that rubber hose/90 and into that valvecover.
Then the air will circulate around the crank case, and there will be a PCV valve on the other valve cover that goes to the top of the intake manifold which pulls in the air/oil mix for combustion.

So normally when you see oil on the breather side, that means something in the PCV system isn't working right.
The PCV valve could be clogged (happens every 100k or so), the hoses could be clogged or have buildup, or where it goes into the intake manifold can be clogged, etc..
It is usually the PCV valve and if you catch it early enough the hoses should be clear for the most part.
If the hoses look suspect take them off and a little compressed air can do the trick on those... make sure they don't have a split at the end, if so replace it with some good quality hose (not vacuum stuff but like heater hose or PS hose).
I would start with replacing the PCV for good insurance, and keep an eye on the valve cover gaskets after that.

When the crank case blow by gasses can't go through the PCV like normal, it builds pressure causing leaks (valve covers), and backs up the breather side and into your intake.
If you pull your intake hose and see oil stuff, then you need to just clean your PCV system out.

I would maybe tackle that first, cause if it is a pressure issue due to a bad PCV then you could redo the valve cover gaskets and still have a leak over and over again.

 

I've never changed my V/C gaskets on my '96 with no leakage.
I will bet that more V/C gaskets leak from being too tight than not tight enough.
General rule for V/C gaskets is to use a good sealer to attach to cover then progressively snug them evenly in as much a cross pattern as possible.
I've never torqued V/C gasket and never had a leaker.

 

The rubber gasket presses in to the cover over an eighth of an inch... it's really not neccesary to seal the gasket to the cover. It will also cause major problems down the road when the gaskets have to be replaced again, and you have to dig a bunch of shit out of that groove, to get the next set of gaskets in.

 

Taking a gasket/cover off and seeing someone smeared RTV all over it is the worst. There are only a couple spots that should have RTV on it, specified in the service manual (half moons and cam caps like most yota's)
It is tedious to remove RTV off an aluminum head without scratching it, and once you scratch it you pretty much have to use RTV for it not to leak.

quick search showed this, the FIPG or RTV black goes in the dark spots only.

 

I definitely recommend folks follow this(the factory service manual)in regard to the FIPG added on only where the the FSM indicates, usually the half moons as you and the manual suggest