The correct valve cover sealer for rubber gaskets

[57retsoor]

When doing a valve cover gasket replacement on a 2002 E39 M54;
After seeing so many different ways of doing this job posted here and elsewhere on the internet, I set out to discern the correct way to do this. My quest, has led to conversations with Permatex, auto store manager(s), and others that the correct aspects of this job are as follows:
Permatex Ultra Rubber gasket sealer & dressing, part # 85409 is the one to use and that RTV is not appropriate for a rubber gasket on any car for that matter because it contains silicone. Additionally, that you only and always dab the half moons in the corner (4) and the tiny valley where the vanos meets the head in the front )small bead), and NO torque wrench because they cannot be verified as calibrated for 6lbs, rather one should finger tighten, then using a 1/4 ratchet, in a criss-cross pattern, ending at the front center bolt, only far enough to begin to compress the gasket. Also rarely mentioned, a cure time of 9 hours for the sealer. Finally, not following any of these factors, could result in a leaking "new" valve cover gasket. If this is correct, why is there so much of a variance in these progressive procedures? Any debate(s) from experienced people?

[gmak]

Nice research. I agree with the no torque. Too many stories of these things stripping. Plus, too much compression seems to lead to a premature hardening of the little rubber donuts themselves.

But, why is silicone not allowed? Is this because of possibly contact with oil? Or is it because of some kind of reaction between silicone and rubber (I've never heard of one)?
I do know that silicone sealants break down under UV (the sun) - but I don't think that it will be shining on these half moons. RTV is good for high temperature, high stress applications. In fact, IIRC, it was developed for aircraft applications.

I think that part of the issue is, after applying the bead of RTV, most don't wait 15 minutes. I would argue that the bead gets smeared when the valve cover is put on - another thing that impacts the RTV performance. Also, one shouldn't torque down the valve cover initially, just to where there starts to be resistance. Then wait an hour, and then finish tightening the valve cover screws by hand using just the junction of the socket extension - so no leverage.

BTW, I use silicone hoses for my vacuum hoses and they hold up better under heat than the old rubber ones.

[jicaino]

Good point. I use a Permatex rubber dresser/sealer for my VCG. I don't care for those swearing "by the book" and installing them with no sealer "because TIS says so". We're talking almost 20 years old crap magnesium alloy that's prone to rust, warp, wear, rust in the form of bubbles that crack away leaving porous mating surfaces...

I lay a very thin 3/32" sealant bead all around the VCGs. They have like 3 channels on the mating surfaces, separated by rubber fins. I use the center one for obvious reasons. Then I lay a little extra on the half moons. I use it on the spark plug well gasket too and on the grommets. Then torque it down using a screwdriver handle that has a 1/4" drive adapter.

Another key factor to this job would be waiting for the sealant to develop a surface skin, then install things. And thoroughly clean mating surfaces, feeling with your finger around to detect any mars, burrs or nicks that could hurt the gasket and create a leak pathway.

I believe that the sealant I use is that you've referenced, I will check as soon as I get to my car tools stash.

[djb2]

The torque doesn't have anything to do with compressing the rubber washers/gaskets. The shoulders on the nuts set the gap. The resilience of the rubber sets the compression and handles thermal expansion.

The reason for using a torque wrench on the nuts is to avoid stripping the studs out of the head. Once the nuts are seated, there is a hard connection to the head. There is a minimal length of stud to stretch before the weakest part yields, and that part is the aluminum threads on the head rather than the far less expensive steel fasteners. I use a 1/4" click type torque wrench, but I always test it on a larger fastener first to make certain I can feel the very subtle click. It's not worth the risk if you don't have a small torque wrench that you have practiced with. Just use a very timid touch when tightening, and stop when you feel the nut bottom out.

Following the numbers on tightening pattern exactly isn't critical. It is critical that you start from the middle and work to the outside edge. If you clamp down the outside edge while the middle is bowed up, you will crack the valve cover when you try to force it flat. That's not a theoretical risk, it has happened to many people here.

Putting sealant on the fins of the gasket completely defeats their purpose. Those fins work the same as o-rings. With no differential pressure, they concentrate the clamping force on a single line. With differential pressure the sealing force is increased.

The fins don't work well at a sharp angle for the same reason o-rings won't work well. That's why you put a very slight dab of sealant in the half moon, and where the VANOS casting meets the head.

[edjack]

Ordinary silicone sealant can poison O2 sensors, although I can't imagine how it could reach them from the valve cover gasket.

Permatex, et al, have "sensor-safe" silicone. Their Ultra Grey, 599BR, so states on the tube.

Torque measurement, from cn90

Finger torque wrench
For difficult small nuts and bolts (in tight space that you cannot fit a torque wrench), I have this best-kept secret that I use for years with success.

It is called 1-finger, 2-finger, 3-finger trick.
As everyone has different strength, the finger strength is also different.
But the variation in finger strength in person A and B is not as big as the variation in biceps strength.

- Hold the gauge-type (the type with needle pointing to a ruler) torque wrench against something: a socket against a stationary bolt, or the torque wrench end clamped by a vise.
- Pull with 1-finger (hand stationary, just pull the finger like pulling the gun trigger): usually 1 finger gives you about 10-15 ft-lb of torque.
- 2-finger: about 20 +/- 5 ( range 15-25) ft-lb of torque.
- 3-finger: about 30 +/- 5 (range 25-35) ft-lb of torque.

It is not scientific but it serves me well in difficult situations (tight space etc.).
Cn90
http://www.bimmerfest.com/forums/sho...d.php?t=533975

[jicaino]

The torque doesn't have anything to do with compressing the rubber washers/gaskets. The shoulders on the nuts set the gap. The resilience of the rubber sets the compression and handles thermal expansion.

True

The reason for using a torque wrench on the nuts is to avoid stripping the studs out of the head. Once the nuts are seated, there is a hard connection to the head. There is a minimal length of stud to stretch before the weakest part yields, and that part is the aluminum threads on the head rather than the far less expensive steel fasteners. I use a 1/4" click type torque wrench, but I always test it on a larger fastener first to make certain I can feel the very subtle click. It's not worth the risk if you don't have a small torque wrench that you have practiced with. Just use a very timid touch when tightening, and stop when you feel the nut bottom out.

there's no hard connection to the head. The shoulder nuts bottoms over the camshafts oilers retaining nuts, and the stud is mounted over the camshaft caps. Those studs are on a threaded hole that has an oil passage on the side. You don't want to mess them up because there's no replacement part available and given the nature of the thread, with a sideways oil port coming in at a 30° angle, inserts or other repairs are really complicated if possible at all. That's the reason for using a torque wrench. Ask me how I know...

Following the numbers on tightening pattern exactly isn't critical. It is critical that you start from the middle and work to the outside edge. If you clamp down the outside edge while the middle is bowed up, you will crack the valve cover when you try to force it flat. That's not a theoretical risk, it has happened to many people here.

True

Putting sealant on the fins of the gasket completely defeats their purpose. Those fins work the same as o-rings. With no differential pressure, they concentrate the clamping force on a single line. With differential pressure the sealing force is increased.

The fins don't work well at a sharp angle for the same reason o-rings won't work well. That's why you put a very slight dab of sealant in the half moon, and where the VANOS casting meets the head.

No, this isn't accurate. the fins are there to act as compartimentalization of possible leaks, much like the lower portion of a vessel's body. If there's a leak, you have 3 wipers creating 4 separated chambers, decreasing the chances of a tiny nick creating a path for a major leak. I use a very thin chord of sealant in the middle space of the fins, to increase the sealing chances over old parts that might not compress the fins evenly, or to avoid a nick in the mating surfaces creating a leak pathway.

Ordinary silicone sealant can poison O2 sensors, although I can't imagine how it could reach them from the valve cover gasket.

The reason for avoiding silicone sealants is because most of them release acids when curing. Said acids are known to eat away pain, metals and create more harm than what they prevent. Permatex has a non acid releasing formulas in their pro gasket makers RTVs.

[JimLev]

This is the stuff to use, I've been using this for 20+ years. It's O2 safe.
https://www.permatex.com/products/ga...asket-maker-4/

[geargrinder]

Totally agree w djb2.

"Can't be calibrated" is total bullcrap. "Most gorillatards only have a 1/2" torque wrench" is what they are REALLY saying. I have 5 torque wrenches in different ranges and drive sizes. 72" lbs is easily done with a small wrench. Not that I use one just saying. That's BS.

And IMO, obsessing over what sealant is "perfect" is a little ridiculous. Yes I use quality RTV, but it's not rocket science and the rubber/aluminum joints it's needed for are far from any extra special engineering application for jebus sake, it's same rubber gasket and half moon and alu head joints that loads of cars have. 900 billion of these jobs have been done successfully with normal RTV or anaerobic sealer and held up fine.

In fact the whole job isn't THAT fussy and difficult or danger fraught. Get the main points down and use care and detail and it'll be fine.

I do personally take a firm view that slathering the whole gasket is improper, and that judicious dabs are the ideal method. I do know my friends Jim and Juan differ and they are men of impeccable credentials, but that's my view.

[Mach540]

And IMO, obsessing over what sealant is "perfect" is a little ridiculous. Yes I use quality RTV, but it's not rocket science and the rubber/aluminum joints it's needed for are far from any extra special engineering application for jebus sake, it's same rubber gasket and half moon and alu head joints that loads of cars have. 900 billion of these jobs have been done successfully with normal RTV or anaerobic sealer and held up fine.

In fact the whole job isn't THAT fussy and difficult or danger fraught. Get the main points down and use care and detail and it'll be fine.

I don't know... I've heard bad things can happen if you use a non-O2 safe RTV in place of approved anerobic rubber compounds.........
28xp-challenger1-master495.jpg

(PC correctness be damned........ Trump allows it now)

[philly98540]

I use what Jim uses. Love ultra black.

I never use a torque wrench on vc. Gradual tighten in multi passes till the nuts just bottom out. Easy peasy never stripped anything. Don't over think it.

[JimLev]

I have at least 3 torque wrenches, the smallest has 1/4" drive.
Do I use it on the valve covers, the upper and lower timing covers, or the intake manifold?
Hell no, waste of time on all of these little nuts and bolts.
Was it Obie One that said.....you can feel the force?

[geargrinder]

I use what Jim uses. Love ultra black.

I never use a torque wrench on vc. Gradual tighten in multi passes till the nuts just bottom out. Easy peasy never stripped anything. Don't over think it.

Totally agreed. Just sayin'. "Can't measure 6ft lbs" is preposterous. You don't need to. But its absolutely normal if you had to. I measure torque settings in that range on the bike frequently (mainly for the carbon related fasteners where indeed its important so you don't crush stuff).

[StRaNgEdAyS]

I've used inch pounds before...

Absinthe makes the tart grow fonder

[djb2]

there's no hard connection to the head. The shoulder nuts bottoms over the camshafts oilers retaining nuts, and the stud is mounted over the camshaft caps. Those studs are on a threaded hole that has an oil passage on the side. You don't want to mess them up because there's no replacement part available and given the nature of the thread, with a sideways oil port coming in at a 30° angle, inserts or other repairs are really complicated if possible at all. That's the reason for using a torque wrench. Ask me how I know....

This is the M54 engine, where all of the studs are coming directly out of the head casting. The M62 is different.

[jicaino]

This is the stuff to use, I've been using this for 20+ years. It's O2 safe.
https://www.permatex.com/products/ga...asket-maker-4/

All of Permatex's stuff ranges from very good to outstanding, even if you don't get the ultra-OCD matching specs variety

Totally agree w djb2.

"Can't be calibrated" is total bullcrap. "Most gorillatards only have a 1/2" torque wrench" is what they are REALLY saying. I have 5 torque wrenches in different ranges and drive sizes. 72" lbs is easily done with a small wrench. Not that I use one just saying. That's BS.

And IMO, obsessing over what sealant is "perfect" is a little ridiculous. Yes I use quality RTV, but it's not rocket science and the rubber/aluminum joints it's needed for are far from any extra special engineering application for jebus sake, it's same rubber gasket and half moon and alu head joints that loads of cars have. 900 billion of these jobs have been done successfully with normal RTV or anaerobic sealer and held up fine.

In fact the whole job isn't THAT fussy and difficult or danger fraught. Get the main points down and use care and detail and it'll be fine.

I do personally take a firm view that slathering the whole gasket is improper, and that judicious dabs are the ideal method. I do know my friends Jim and Juan differ and they are men of impeccable credentials, but that's my view.

I have to say that I agree, it's a no-rocket-sci job. Just think of a way of doing it that would let you sleep at nights without trippin' about leaks you cannot see and will result in total engine failure...
I lay a sealant string (it looks like a string) applied with a syringe because I've always do it that way and never ever had a minuscule leak, or issues to take it out afterwards. I have a personal friend and BMW indie that's really knowledgeable and he swears by the TIS method, and while he does a fine job, he's not 100% leakproof. Maybe less of a 10% chances of having to reseal using his way...
To give you an idea of how little product I use, when you undo one of my VCGs you don't know sealant has been added. It's no NY deli "schmear"...

I don't know... I've heard bad things can happen if you use a non-O2 safe RTV in place of approved anerobic rubber compounds.........
28xp-challenger1-master495.jpg

(PC correctness be damned........ Trump allows it now)

Let's just say if you use that stuff at least invite a school teacher and other inocent civilians on your first test drive... :mrgreen:

I have at least 3 torque wrenches, the smallest has 1/4" drive.
Do I use it on the valve covers, the upper and lower timing covers, or the intake manifold?
Hell no, waste of time on all of these little nuts and bolts.
Was it Obie One that said.....you can feel the force?

I always use torque wrenches and screwdrivers because having worked many years with cast iron engines I pound like a gorilla and strip a lot of threads in the M5-M10 range. When I work with anything under M4 my brains activate the "sax mechanic" mode and I'm safe. For car/bike/mechanic work I have a screwdriver handle ranging from 0 to 100 Ncm, a small 1/4" drive and a medium 3/8" drive torque wrenches that conveniently overlaps ranges so I don't have to work near the end of the scale where they're less dependable. And I own a decent chinesium 1/2" drive torque wrench that I very seldomly use. I even measure my wheels bolts tq... better to be safe than sorry... and although I have an extensive knowledge and equipment for thread repairs (helix and shell inserts, and whatnot) there's some locations I'd rather not have to monkey around.

This is the M54 engine, where all of the studs are coming directly out of the head casting. The M62 is different.

Sorry, I don't know why I always think all cars are my car.

[geargrinder]

Let's just say if you use that stuff at least invite a school teacher and other inocent civilians on your first test drive...

Ha ha. When that happened, one of my best buds was living in NH, where school teacher was from... The true classic pre-PC joke:

"What was the last thing she said to her husband before blast-off?"

"OK Honey you feed the dogs, I'll feed the fish"

badumbump. OUCH.

Sorry, I don't know why I always think all cars are my car.

Cuz best kar.

[jicaino]

Ha ha. When that happened, one of my best buds was living in NH, where school teacher was from... The true classic pre-PC joke:

"What was the last thing she said to her husband before blast-off?"

"OK Honey you feed the dogs, I'll feed the fish"

badumbump. OUCH.

Ohhhh poor Mrs. McAuliffe! that joke tho, it's worth being in the apollo's gold record. It sums up so much of humans' sense of humor...

Cuz best kar.

Awww c'mon you say that to all them 540i's

We all know the truth tho, the best car is a V8 manual touring with a long veiny... errr... S/C. Thanks for not rubbing our faces on our turds

[57retsoor]

My procedure for the valve cover gasket, conclusion:
I finally got this gasket right and wanted to share my experience so others can do this job with confidence.*****
The gasket: Victor Reinz with spark plug and valve cover grommets (4) on the head (11) around the outside. The gasket goes into the valve cover, not on the head.
Sealer: Permatex Ultra Rubber Gasket Sealer & Dressing (Gray)
Skinny, small bead on the vanos “crack” (both sides) about the size of 2 toothpicks, and a dot only in the corners (4) of the half moons.
Torque/sequence: Begin at the (4) 10mm nuts in the center/middle of the head where the coils are. Three of these have ground straps with 8mm nuts on top of the 10mm nuts. Careful not to re-torque the 8mm nuts when reattaching the grounds. Next, start at the middle top nut on the valve cover, then middle bottom nut; work your way towards the back and front alternating going back and forward, so as to torque the next ones towards the firewall, then next towards the front of the engine, ending up at the forward most (odd ball) where the vanos is. I set the 0-200 pound torque wrench borrowed from Autozone at 6 pounds, and re-checked each time I tightened a nut. I also practiced on another bolt elsewhere (the airbox) to get the feel and sound for 6 pounds because I have read of the inaccuracies of torque wrenches, specifically, the top and bottom 15% of the torque wrench range is not entirely reliable. The “click” sound is so faint that if a cricket chirps, you’ll miss it.
When you get close to feeling a resistance on the wrench slow down, watch and listen.
This TW had a wiggle from the directional toggle (the one that decides counter or clockwise rotation) just before the click. I held my breath every time I tightened one, hoping to hear a click instead of a snap. The errors I made the first time was not aligning the valve cover exactly centered on the studs which looks like an ever so slight adjustment looking down through the holes at the studs-and a torque pattern in a zig zag fashion across the head, top, middle, bottom.
The first time, there was still some smoke from the passenger side/firewall bolt area to the next bolt forward. I loosened the nuts just enough to move the entire valve cover and gasket without lifting it off the head, again, probably only moving it a millimeter or less, but it made the difference getting them as close to center as possible. Whoever did this job before had so much black goop on the gasket and valve cover it took 2 of us half a day to get it all off with rubbing alcohol, a plastic credit card, and rub, rub, rub. It was so much that I think it literally changed the shape of the gasket meeting the head, the built in grooves of the old gasket had this crap covering the grooves so as to make it flat. I could not get a torque wrench on that back corner nut (cylinder 5) so I just bottomed it out with a 10mm box wrench; carefully. Be patient; go slow with these nuts/grommets allowing them to seat as you are turning them down.
Thanks for all your input. I did an amalgamation of all the opinions.
Glad it’s done and above all, smokeless!

[Tarquineous]

Thanks. Your post is the most professional and gives reasons for things like the compression of the rubber bolt grommets.
I would like to add; The Fel-Pro company has videos saying not to use gasket dressings except for corners and discontinuities. The material of the gaskets, and coatings on thin gaskets give a better seal than goops and adhesives. The cleaning of surfaces and flatness is important.

[JimLev]

I would like to add; The Fel-Pro company has videos saying not to use gasket dressings except for corners and discontinuities. The material of the gaskets, and coatings on thin gaskets give a better seal than goops and adhesives. The cleaning of surfaces and flatness is important.

That must be a different material than what BMW uses. All BMW gaskets will leak after a few years, unlike the gaskets used on Japanese car engines.