1G Any tricks to sealing valve cover?

[dwb]

My valve cover tends to leak along the front side of the head. No matter what I do, I always find a bit of an oil leak coming from the valve cover gasket area. Sparkplug wells are dry. I have all original OEM hardware, no stripped bolt holes and original valve cover. Sealing surface is clean and no gouges.
I've tried several new OEM gaskets, no RTV except for the aluminum half moon (which isn't leaking). Initially I install the bolts with a hand driver, just snug. Then I gradually tighten them over time (months) to see if I can get it to seal. I eventually end up splitting the gasket because the bolts get over torqued.

I've ordered another new OEM gasket and will give it another try, but what's your trick to getting it to seal up?

 

[RamenPride]

The valve cover most likely has a crack

 

[pauleyman]

Do you have excessive crankcase pressure?

 

[dwb]

The valve cover most likely has a crack

No, not this leak. It's right on the seal. I do have a hairline crack up near the plug wire organizer/hold down bolt which I'm not concerned about.

Do you have excessive crankcase pressure?

Shouldn't be, it was a fresh engine about 3-4k miles ago.

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[DreamChaser7]

Buy a Frontline Fab VC? Lol

 

[97egl]

I personally have had good luck with felpro valve cover gaskets. No experience with new OEM and probably not the issue but figured I'd throw that out as an option.

When I tighten the bolts I lightly snug the center bolts from middle out to the sides and then do the same thing to the outside bolts. Then go back thru and tighten to 15 inch lbs or whatever the spec is. Can't remember but its not a lot. If you just hand tighten by feel normally you'll go tighter than the manual calls for which I have done and got leaks from the gasket getting pushed out.

 

[DSMPT]

If you have a new seal, that's most likely caused by crankcase pressure. If that's the case, it will leak even with a new seal. The best way to avoid this leak would be having a better crankcase ventilation or fix the cause. Did you check the PCV valve for leak?

 

[fourgsixty3]

So is it leaking by the cam gears or by the half moon? If it's by the cam gears I've always put a little RTV in between those cam caps and the head. I've also put some RTV in the corners of those caps before installing the VC.

 

[dwb]

I personally have had good luck with felpro valve cover gaskets. No experience with new OEM and probably not the issue but figured I'd throw that out as an option.

When I tighten the bolts I lightly snug the center bolts from middle out to the sides and then do the same thing to the outside bolts. Then go back thru and tighten to 15 inch lbs or whatever the spec is. Can't remember but its not a lot. If you just hand tighten by feel normally you'll go tighter than the manual calls for which I have done and got leaks from the gasket getting pushed out.

I hadn't really thought about the order in which I tightened them. Something I'll have to pay attention to. I've always used a hand driver, not a ratchet or wrench, for my initial torque. Maybe this is even too much?

If you have a new seal, that's most likely caused by crankcase pressure. If that's the case, it will leak even with a new seal. The best way to avoid this leak would be having a better crankcase ventilation or fix the cause. Did you check the PCV valve for leak?

I've got all the OEM CC vents, PCV is OEM and maybe two years old and routes to the intake mani like stock. No leaks showing up on the PCV when doing a BLT. I route my breather line to a catch can and then into the intake snorkel. I would agree with CC pressure if this weren't a fresh motor. It was showing signs of leaking before the first 1k miles. But you've got me curious now, so I'm thinking a T in my breather line and hooking my manual boost gauge to it. What would be excessive CC pressure measured in PSI?

So is it leaking by the cam gears or by the half moon? If it's by the cam gears I've always put a little RTV in between those cam caps and the head. I've also put some RTV in the corners of those caps before installing the VC.

Not leaking at the half moon or the cams. See my pic above that shows oil residue all the way across the seal.

 

[97egl]

I hadn't really thought about the order in which I tightened them. Something I'll have to pay attention to. I've always used a hand driver, not a ratchet or wrench, for my initial torque. Maybe this is even too much?

A hand driver is what I use as well. And I just go down hand snug on that first pass which wont get you over the torque spec. I can't say that the order helps for sure..... I am the guy that is always going off of torque specs for everything where most people just go with "seems good to me" so the order is probably overkill but it makes me feel better

Another possibility could be that the valve cover is warped somehow? But I'd think it would have to be pretty significant to cause a leak. Just a thought

 

[DSMPT]

I've got all the OEM CC vents, PCV is OEM and maybe two years old and routes to the intake mani like stock. No leaks showing up on the PCV when doing a BLT. I route my breather line to a catch can and then into the intake snorkel. I would agree with CC pressure if this weren't a fresh motor. It was showing signs of leaking before the first 1k miles. But you've got me curious now, so I'm thinking a T in my breather line and hooking my manual boost gauge to it. What would be excessive CC pressure measured in PSI?

I don't know how quickly become like the pic in your case but to be honest, this is kind of chronic disease of 4g63. Even the engine is freshly built with new gasket, the crankcase has positive pressure and oil would seep out from the valve cover gasket little by little by time.
I have never measured the crankcase pressure on a stock built but in my 1g when it had two-10AN open vent ports, I was seeing a couple of psi in crankcase under boost and oil would seep out from the valve cover gasket little by little by time.
I tried a couple of things long time ago (I imagine many people have tried something similar), such as putting two PCV valves in series, applied RTV between the head/gasket/valve cover to seal completely (would be PITA to clean next time when replacing the gasket), double gasket for oil filler cap, replacing the gasket often with new, different valve cover bolts torque/torquing pattern etc, but anyways sooner or later oil seeped out little. So I stopped caring, just clean when I find oil is seeping out.
From my experience, the only way that could perfectly stop the leak for long is having vacuum in crankcase by a vacuum pump. After I installed a mechanical vacuum pump, I see no leak from valve cover/oil filler cap gasket/spark plug hole gaskets/top and bottom of dip stick tube seal, just clean and dry. So I guess this means even with a little of crankcase pressure would push the oil through valve cover gasket by time.

 

[jesse12345]

I found out when mine was constantly leaking that the oil was coming from the cam seals, even though they were brand new. The leak was running all the way down by my filter. Just another idea if you haven't pin pointed the leak yet.

 

[Christo]

I have always went off the OG Vfaq method. I use a very small amount of red RTV in between the valve cover (in the small galley) and the gasket it self where it sets in as well as the half moon/across it and the over the humps. Have had good results with that method.

Parts Needed
*10mm socket w/ extension bar
*Torque wrench (capable of reading 2-3 ft.lbs.)
*Valve Cover Gasket (MD 125939 $24)
*4-Spark Plug Gaskets (MD 125940 $5.79/ea)
*Cam Shaft Seal (MD 050536 $2.80)
*Hi-Temp RTV Gasket Sealant
*Oil Cap Gasket (MD 311638 $2.98) -Optional

Procedure (see picture)

Remove Top Timing Belt Cover
Remove Oil cap, PCV Valve, and breather hose (above crank angle sensor)
Remove Center Cover (10mm), and all spark plug cables (mark which cable goes where)
Remove the 14 bolts (10mm) holding on the valve cover (8 outer, 6 under center cover)
Remove Valve Cover (mine was stuck so I had to use a rubber mallet to free it)
Remove the semi-circular plug (aka cam shaft seal)
Remove all remaining gasket on block side
Clean both side of the valve cover. I used some carb cleaner and dried thoroughly.
Remove all remaining gasket on valve cover side
Use a SMALL amount of RTV sealant on valve cover side with the spark plug seals and main valve cover gasket
Use RTV sealant on semi-circular plug and the 2 camshaft and crank angle sensor humps (see illustration)
Remove any excess sealant
Replace valve cover and torque bolts to 2-3 ft.lbs. (2.5-3.5 Nm)
Remove any excess sealant
Replace items originally taken off in steps 1-3
Start engine and check for leaks. Check for leaks periodically.

Optional
If you haven't changed you oil cap gasket before, it probably needs it now. The tell-tale signs are oil leakage around the oil spout and oil build-up under the center cover.

 

[dwb]

A hand driver is what I use as well. And I just go down hand snug on that first pass which wont get you over the torque spec. I can't say that the order helps for sure..... I am the guy that is always going off of torque specs for everything where most people just go with "seems good to me" so the order is probably overkill but it makes me feel better

Another possibility could be that the valve cover is warped somehow? But I'd think it would have to be pretty significant to cause a leak. Just a thought

TBH, I've never owned a in-lb torque wrench. I only use a torque wrench on things that are critical. I'm usually pretty good at torque-to-feel.
This valve cover has spent it's entire life under that hood, except for a few months last year during rebuild. I suppose it *could* be warped, but not my first guess.

I don't know how quickly become like the pic in your case but to be honest, this is kind of chronic disease of 4g63. Even the engine is freshly built with new gasket, the crankcase has positive pressure and oil would seep out from the valve cover gasket little by little by time.

Maybe a couple months of daily driving. It's probably worse now since I've been gradually torqueing the bolts down in an attempt to mitigate the leak. It's definitely been a disease on mine ever since 1999.

I found out when mine was constantly leaking that the oil was coming from the cam seals, even though they were brand new. The leak was running all the way down by my filter. Just another idea if you haven't pin pointed the leak yet.

Cam seals are good.

I have always went off the OG Vfaq method. I use a very small amount of red RTV in between the valve cover (in the small galley) and the gasket it self where it sets in as well as the half moon/across it and the over the humps. Have had good results with that method.

Optional
If you haven't changed you oil cap gasket before, it probably needs it now. The tell-tale signs are oil leakage around the oil spout and oil build-up under the center cover.

Not a big fan of RTV where not called for in the FSM. Otherwise I'd just RTV the shit out of it and call it a day in hopes I never have to remove the VC again.
I can't tell you how many oil cap gaskets I've gone through. I have another new one in the mail. I replaced the oil cap gasket on my Highlander a few weeks ago for good measure and noticed the old one was still nice and supple, and it's from 2006 with over 200k miles. Too bad it wasn't roughly the same size, I'd toss a Toyota gasket on my DSM in a heartbeat.

 

[Christo]

I hear you. It is a very small amount, It is not enough to make the valve cover not removable and it is mostly between the gasket and the valve cover, not the head. It does help the seep that it looks like you are dealing with along the front there. Hope you get it worked out, keep us updated.

 

[steve]

(3Nm, 2.2 ft.lbs) You may not have a torque wrench that goes that low and is reliable. It's so easy to exceed it and crack the rocker cover it's not funny.

This is about the amount of force required to flatten a split washer and you can do it with one finger on a 1/4" socket wrench so be careful. It would be easy to exceed this even with a hand driver. If you over tighten the rocker cover you will distort the gasket and it won't seal. If the gasket isn't soft it's old and won't work correctly.

This gasket is dead.

 

[We're on Boost]

Not a big fan of RTV where not called for in the FSM. Otherwise I'd just RTV the shit out of it and call it a day in hopes I never have to remove the VC again.

I'm not a big fan of it either. If you do use it there, don't RTV the shit out of it. Google "BRZ RTV issue" and you could spend half your day reading about it.

I took a close look at my VC gasket area just now because it is not leaking at all, no seep at all. I can't see any RTV coming out anywhere except at the half-moon seals. But I don't know for sure what they did in there (English Racing). All I know is, the VC gasket is black rubber (don't know if that is after market or OEM) and there are 2 unrestricted hoses coming out of the cover for pressure relief. No little filters on the hose ends or catch can or anything like that. Just dumps.
Maybe it's possible that they might have used a microscopically thin smear of RTV or some other sealant on the gasket and it just didn't come out anywhere? Wish I knew. I do know they like the Ultra Grey RTV for some things and they used it in some other places on the engine.
The only little oil seepage I have anywhere is at the bottom of the dip stick tube, like Hiroshi mentioned.

 

[dwb]

This gasket is dead.

Indeed it is. That's because I over torqued it since "proper" torque (IMO) in the beginning didn't seal it. It's only about 10 months old too. I have a new one in the mail.

I'm not a big fan of it either. If you do use it there, don't RTV the shit out of it. Google "BRZ RTV issue" and you could spend half your day reading about it.

I was being fictitious, I'd never put *that* much RTV on. But holy hell, the BRZ RTV issue sounds like an absolute nightmare straight out of the factory. That's why I like to use only the proper gaskets where applicable. If it uses a gasket or seal, it shouldn't need anything else in most cases. RTV on the oil pan makes me a bit nervous, but that's how it's done.

 

[pauleyman]

I hadn't really thought about the order in which I tightened them. Something I'll have to pay attention to. I've always used a hand driver, not a ratchet or wrench, for my initial torque. Maybe this is even too much?


I've got all the OEM CC vents, PCV is OEM and maybe two years old and routes to the intake mani like stock. No leaks showing up on the PCV when doing a BLT. I route my breather line to a catch can and then

A sealed or vented can?

into the intake snorkel. I would agree with CC pressure if this weren't a fresh motor. It was showing signs of leaking before the first 1k miles. But you've got me curious now, so I'm thinking a T in my breather line and hooking my manual boost gauge to it. What would be excessive CC pressure measured in PSI?


Not leaking at the half moon or the cams. See my pic above that shows oil residue all the way across the seal.

 

[dwb]

A sealed or vented can?

Sealed catch can.

 

[dwb]

For thoroughness, here's what I can find in the FSM:

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[Spleen8urLSX]

I’ve always followed factory sequence and in-lbs torque spec and never had an issue. This is with both felpro and the cheapest ones I can find on eBay, never had my hands on an oem one as I’ve never had a desire or need to pay the oem mark up however I suspect the cheap eBay ones are probably from the same exact factory in Malaysia or Taiwan or wherever. A good torque wrench that reads in in-lbs is a good investment if you own one of these just for the valve cover alone.