Glen H

My 1998 C43 valve cover gaskets have been replaced for leakage at 142k, 152k and now 161k. They have become an expensive 10k maintenance item. My long term mechanic says the covers are aluminum and likely have some warpage. Is this likely the case, would replacing them likely solve the problem, and is replacing them the only viable approach? They are quite expensive.

speed43

Just use permatex right stuff and will last much much longer. Have your mechanic put a small amount on top and bottom of the rubber gasket and that's it.

I use this stuff to seal the half part of intake manifold and I've never have any vacuum leaks. This sealant is VERY good. Just make sure to let it dry as many hours as possible before driving. I once did a car with this and had to drive out after half an hour and no leaks to this day and it's been close to 2 1/2 years. But if I could let it dry for hours I would.

Don't let your machanic convince you that you shouldn't use a sealer. IF your valve covers are really warped this will fix that. It's that good!

https://www.amazon.com/Permatex-25224-Right-Stuff-Gasket/dp/B000HBM4FQ

DRBC43AMG

Never have heard the covers warping on M113 engines but could be wrong. Have you an indication where the leak(s) are coming from? Breather top covers or at the bottom of the valve cover?
As Speed43 says a good quality sealant is a must and if done correctly should last as long as the engine does
Did mine on both sides top and bottom in 2012. No problems since.

ProjectC55

This is how I fixed my oil leak. The valve covers and breather cover surfaces need to be cleaned properly.

https://mercedessource.com/store/m11...s-demand-video

nkctb7

The valve covers are NOT aluminum. They are magnesium! I've never heard of warped magnesium valve covers nor have I ever heard of anyone replacing vcg's every 10K miles. Perhaps there are invisible hairline cracks that have worsened over time. It sounds more like the oil breathers that aren't being sealed properly. Out of curiosity, how much is your mechanic charging you for the vcg's and per vcg replacement?

mickey13

he said it was an "expensive" 10k repair item. sounds like he just learned about the "mercedes tax" every dealership and some mechanics believe they have the god-given right to charge.

ProjectC55

I cleaned the surface of the head and the valve covers thoroughly. No sealant at all but what is important is that the valve cover bolts are ALL bolted to specs in two stages(4NM then 8NM) with a torque wrench. With no sealant used all I can say is so far so good NO LEAKS. The thing that really leaks if not cleaned properly are those silly breather covers which must be cleaned thoroughly or they will leak like a siv. just check the video that I posted above. If you torque/tighten the valve covers unevenly she will leak

ItalianJoe1

More and more of these are showing up with porosity in the covers, requiring replacement. If they are leaking every time, that may be what's happening. You do need to ensure the covers are being cleaned and sealed properly.

PJmak

Definitely should not have to replace those that often.

KJI3jflarryfe93

what are the tightening bolt procedure for valve cover gaskets?

do we have anyone with WIS who can show in what order to tighten first bolt then go to bolt no.2 then bolt no.3 etc. etc.?
there's a thread on C63 forum, these valve covers have 13 bolts or so?
someone posted the tightening steps for valve cover bolts.

I can't find them for C43.
need a WIS sketch for C43.

speed43

See thread below, the guy mentions top middle to down middle than going out to the sides.,...

http://www.benzworld.org/forums/show....php?t=2273162

KJI3jflarryfe93

thanks

according to Benzworldlink,
seems like there are different lengths for valve cover bolts, it's easy to screw the wrong bolt length to wrong place

speed43

If it worries you get a cardboard box and make an outline of the valve cover pattern. Punch some holes where the bolts should go. Than as you pull one boltbout stick it in the proper hole. Can't mess up like that. I've done three c43s valve cover gaskets and have never needed to do this. Not a hard job at all. Use a little silicone on both sides of the rubber gasket for 100 percent seal. Otherwise, you have to be precise bolting the bolts down.

KJI3jflarryfe93

there should be a stickie for this gasket swap valve cover job.

torque is 9NM according to MB.

yeah, that's a good idea cutting out a V-cover stencil from cardboard paper then punching each bolt in the right place.

the only issue is to tighten correct bolt first, then go with the other ones in correct order

see bolt tightening for C63 the first reply
.https://mbworld.org/forums/c63-amg-w...l-leaking.html

we need a WIS stickie for C43

ItalianJoe1

KJI3jflarryfe93

thanks for the info.

ProjectC55 mentioned in his previous reply when everything is cleaned properly, new gasket is fitted then put V-C back to it's place.
The first round when tightening each and every bolt, is to tighten each bolt with 4NM.
The 2nd round to tighten each and every bolt with 8NM.
WIS says 9NM.

I only want to re-tighten my bolts not doing any replace for V-C gasket.
These engines with age or mileage builds up will eventually weep their own pants.

How much torque do these bolts handle before they snap?
If you have bad luck to snap one bolt , then a helicoil is necessary.

DRBC43AMG

Why do you want to re-tighten the valve cover bolts? If you don't have any oil leak, I would leave them alone. Don't disturb the devil inside IMO

KJI3jflarryfe93

on one place, have a tiny stain of olio coming out down on sparky plug.
I want to tighten this bolt, therefore wudd be good to know the bolting order from first to last for futura references if I discover more leaks.

there shudd be a sticky DIY for this VC job, everyone will experience this problem sooner or later.
If we have a sticky thread then we all know the procedure of cleaning, replacing and refitting everything back 2gether.

there are no sticky DYI threads for our C43.

ItalianJoe1

Same torque. The gasket will compress over time, and it will take more turns of the screw to reach that same torque. 9Nm is nothing, barely hand tight with a screwdriver. I have done so much mechanical work I know about what you need for the fasteners in question by feel, but it should be moderately tight. Go around them all several times, on a large item like a valve cover, with small screws, as you tighten more of them, the first ones will loosen. If you just went around one time, the first ones you did will probably not be tight enough. keep bringing them all back to the same tightness, until they don't loosen up as you come back to them.

KJI3jflarryfe93

how is it possible screws go loose after the first time screwing bolts back to VC?
ain't it better using Loctite in bolt threads, screws won't loosen up again?

how many spanner turns do these bolts handle with a torque wrench?
bolts will eventually snap messing with them too much?

ItalianJoe1

The rubber seal compresses and shrinks, so it no longer provides the same sealing it used to, nor the same tension.

vinceC

The valve covers have a "spacer" cast into them at each bolt location. That ensures that the correct gasket crush takes place. Once the bolts are torqued correctly the "spacers" will be in contact with the head. No amount of overtightening will add crush to the gasket. If they leak they need to be replaced. See the photo.

KJI3jflarryfe93

thanks.

I have some oily sweat stains on certain places which comes with age or miles build up

vinceC

That weeping is inevitable with age. As long as the bolts are still keeping the "spacers" snug against the head the only solution is to renew the gaskets. Alternatively, just clean the area periodically with a bit of electrical cleaning solvent.

exhaustgases

So with about 50+ years of mechanic experience, rubber or what ever it is made of is the worst material there is for a gasket even cork is better. At least Mercedes attempted to do it correct with the pads to allow tightening crush on the gasket, unlike Lexus did. I have put some of the very worse known leaker engines together and never had a leak.