Valve cover leak...
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Re: Valve cover leak...
Wrung the top off of one of the aluminum Torx socket head cap screws during final tightening. Lucky the material was aluminum. It was simple to extract the screw with an "easy-out". These really have to be only snug tight. I'd recommend nothing more than 1/8 turn after snug.
I did the same thing, last bolt and last little snug. Filled the hole with permatex and will replace all screws when covers start leaking again.
I did the same thing, last bolt and last little snug. Filled the hole with permatex and will replace all screws when covers start leaking again.
Last edited by Grumps; 10-01-2014 at 08:40 PM.
Re: Valve cover leak...
Originally Posted by Grumps
I did the same thing, last bolt and last little snug. Filled the hole with permatex and will replace all screws when covers start leaking again.
Last edited by dedwards0323; 11-13-2010 at 07:06 AM.
Re: Valve cover leak...
Here are pictures of the breather covers installed. The Permatex Ultra Grey Gasket Maker looks a little 'cleaner' on the car than the typical black product. You'll notice that there isn't much excess showing along the sealing edges. That's because I only filled the trough on the breather covers with sealing material, rather than put a heavy bead all around. Used my small pocket knife to sorta level off the sealing trough where necessary. Did the same around the mounting hole areas where sealer was needed. I don't feel it's necessary to use much more.
You'll also see where the carbon steel SHCS's are installed where the aluminum Torx SHCS's normally are used.
So far so good,
You'll also see where the carbon steel SHCS's are installed where the aluminum Torx SHCS's normally are used.
So far so good,
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M60A3Driver (06-26-2023)
Re: Valve cover leak...
Cost at Arrowhead Benz dealer in Peoria AZ for the small bolts was, list $3.08, sold for $2.50 each, $12.50 for all 5. Just mention it's a M312 engine in a SLK 320. Don't bring up Crossfire. These have a hex head instead of Torx. Part number was 000000-004436.
Last edited by bspence; 09-13-2010 at 12:19 PM.
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M60A3Driver (06-26-2023)
Re: Valve cover leak...
Originally Posted by bspence
Cost at Arrowhead Benz dealer in Peoria AZ for the small bolts was, list $3.08, sold for $2.50 each, $12.50 for all 5. Just mention it's a M312 engine in a SLK 320. Don't bring up Crossfire. These have a hex head instead of Torx. Part number was 000000-004436.
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Ddave (08-29-2023)
Re: Valve cover leak...
So after reading this post I went and checked out my covers and they are doing the exact same thing. I'm still under warranty but I'm wondering if I should remove my aftermarket exhaust before going in so they can't say that was the cause of it!
any help is appreciated!
any help is appreciated!
Re: Valve cover leak...
Originally Posted by Egibson
So after reading this post I went and checked out my covers and they are doing the exact same thing. I'm still under warranty but I'm wondering if I should remove my aftermarket exhaust before going in so they can't say that was the cause of it!
any help is appreciated!
any help is appreciated!
Re: Valve cover leak...
I noticed something when I took my intake off. The intake manifold holes are not threaded all of the way.....at least the couple that I looked at. I wonder if the valve cover holes are the same. This might partially explain why so many people have broken bolt heads off......Over-tightening for sure will do it, but it is much easier to do if the hole is not threaded all of the way down.
Just something to think about....
Cheers,
KrzyFast
Just something to think about....
Cheers,
KrzyFast
Re: Valve cover leak...
Originally Posted by dedwards0323
Found out the hard way earlier this morning while fixing the DS breather cover. Wrung the top off of one of the aluminum Torx socket head cap screws during final tightening. Lucky the material was aluminum. It was simple to extract the screw with an "easy-out". These really have to be only snug tight. I'd recommend nothing more than 1/8 turn after snug.
Anyway, went to local M-B dealer for replacement screws. Absolutely no help. Got the impression he didn't want to assist me once I said the screw came off a Crossfire with their 3.2L engine in it. Screw them!
Went to Chrysler dealer down the road a piece. Parts guy was helpful and found the screw I was looking for during his search. Printed me a copy of the attached. Unfortunately, didn't have these screws so I special ordered them out of Gainsville, GA warehouse. He told me I should have them within 3-4 days. $4 each. OUCH! $20 to replace all 5.
Since I didn't want the XFire to be out of service for a single M5-.80x16 cap screw, I went to Lowe's and looked in the metric fastener section in hardware. Low & behold I found M5-.80x16 regular SHCS's for $0.80 each. $4 to replace all 5 on the 3.2L! But if you do this, take extra precaution. The normal SHCS's are Grade 12.9 steel and the valve covers are cast aluminum. So it's easy to strip out threads if you over-tighten. Let the Permatex Gasket Maker compound do the work.
I'll start up the XFire later today & look for any catastrophic leaks. Hopefully, I won't find any. Then it will be only necessary to inspect the valve covers after driving around town the next couple of weeks to make sure that the ongoing leak is eliminated. Gotta have this resolved before Dragon weekend.
Anyway, went to local M-B dealer for replacement screws. Absolutely no help. Got the impression he didn't want to assist me once I said the screw came off a Crossfire with their 3.2L engine in it. Screw them!
Went to Chrysler dealer down the road a piece. Parts guy was helpful and found the screw I was looking for during his search. Printed me a copy of the attached. Unfortunately, didn't have these screws so I special ordered them out of Gainsville, GA warehouse. He told me I should have them within 3-4 days. $4 each. OUCH! $20 to replace all 5.
Since I didn't want the XFire to be out of service for a single M5-.80x16 cap screw, I went to Lowe's and looked in the metric fastener section in hardware. Low & behold I found M5-.80x16 regular SHCS's for $0.80 each. $4 to replace all 5 on the 3.2L! But if you do this, take extra precaution. The normal SHCS's are Grade 12.9 steel and the valve covers are cast aluminum. So it's easy to strip out threads if you over-tighten. Let the Permatex Gasket Maker compound do the work.
I'll start up the XFire later today & look for any catastrophic leaks. Hopefully, I won't find any. Then it will be only necessary to inspect the valve covers after driving around town the next couple of weeks to make sure that the ongoing leak is eliminated. Gotta have this resolved before Dragon weekend.
Later,
Senior Member
Re: Valve cover leak...
Originally Posted by KrzyFast
I noticed something when I took my intake off. The intake manifold holes are not threaded all of the way.....at least the couple that I looked at. I wonder if the valve cover holes are the same. This might partially explain why so many people have broken bolt heads off......Over-tightening for sure will do it, but it is much easier to do if the hole is not threaded all of the way down.
Edit
OK, I see what you are saying, But why would any threads past the screw have any effect on the strength?
There is another method to cut threads in parts rather than conventional tapping, and this may explain what you are seeing.
Initially a hole is made which is larger in diameter than the hole size normally used for the tapping method. A tool which is like a polished screw (with no flutes) is then forced into the hole, turning at the correct thread pitch rate and this tool forms the correct thread form. Material that is in the wrong place is forced into the voids and a strong thread is rapidly formed. The benefit is there are no chips left to be cleaned away just some lubrication fluid.
This system works very well on ductile materials, clean and fast.
Tapping hole sizes are normally about the actual thread root diameter.
Thread formed holes are about half way between the thread root diameter and the thread outside diameter. That puts the difference in the two holes sizes about the thread depth.
Originally Posted by dedwards0323
Picked up the screws that were special ordered from local CDJ dealer. Turns out the replacement screws are zinc-plated and a standard SHCS (not Torx). Anyway, for my $0.02, I'd go to Lowe's and get the screws for $0.80 each rather than buy from either M-B or CDJ dealer.
Later,
Later,
Check to see if they are steel with a magnet.
There may have been a reason why the originals were aluminum.
One reason could be galvanic corrosion, and they may have had cases in some locales, maybe humid coastal areas, where the local conditions caused this corrosion. The use of aluminum screws in the aluminum allow heads would prevent this. Using steel screws which have been plated to prevent contact of the steel and aluminum alloy would also prevent the galvanic action.
With complaints of screw failures it's possible that they opted for the use of the more costly and slightly less safe plated steel screws.
Aluminum is prone to galvanic action with steel and magnesium is even worse.
Last edited by onehundred80; 09-22-2010 at 12:26 PM.
Re: Valve cover leak...
Originally Posted by onehundred80
They do not look like they are zinc plated to me. They look like they are anodized, that's if the colors of the photo are true.
Check to see if they are steel with a magnet.
There may have been a reason why the originals were aluminum.
Check to see if they are steel with a magnet.
There may have been a reason why the originals were aluminum.
Re: Valve cover leak...
The covers are magnesium alloy for sound deadening and weight advantage, the heads and block are aluminum alloy. MB engineers, very smart folks chose to use special aluminum fasteners to avoid dissimilar metal corrosion problems no doubt. Fastening dissimilar metals information here.
http://www.kamax.com/fileadmin/user_...ning_of_mg.pdf
http://www.kamax.com/fileadmin/user_...ning_of_mg.pdf
Last edited by bspence; 09-22-2010 at 01:08 PM.
Senior Member
Re: Valve cover leak...
Originally Posted by bspence
The covers are magnesium, the heads aluminum alloy. MB engineers, very smart folks chose to use aluminum fasteners to avoid dissimilar metal corrosion problems no doubt.
Magnesium, with other materials, is used as an alloying element in the aluminum to improve the final materials properties.
Magnesium is a costly material and is too costly to be used in this part where there is no benefit.
Re: Valve cover leak...
Originally Posted by dedwards0323
These screws are really simple to remove with an 'easy out'. I simply center punched the broken thread & drilled the pilot hole using a 5/64" drill bit. And you don't have drill a very deep pilot hole. Then using a #1 'easy out', the broken screw came right out. (Note: The broken screw is aluminum so the screw extractor or 'easy out' will grab real easy.) Didn't even have to remove the breather cover to perform this repair. And as I stated earlier, I replaced all the aluminum M5-.80x16 Torx SHCS with standard carbon steel Hex SHCS's I found at Lowe's.
When I tried to replace the initial screw (doing these one at a time to minimize losing the new breather cover seal), that extra 2 mm length is enough to make the screw feel like it's either 'bottoming out' or possibly out of threads when tightened (as discussed earlier in this thread). So I stayed with the carbon steel screws from Lowe's. But will continue looking for screws that would be possibly better applicable for use with the valve covers to lessen the likelihood of any chemical corrosion down the road.
Last edited by dedwards0323; 09-22-2010 at 11:48 AM.
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Re: Valve cover leak...
Just putting in my $.02 worth here ...... I seem to remember from working on a trawler I once owned that had an aluminum BMW diesel, that I was told that metals have a pecking order that requires different metals NOT to be used "together", and not use ferrous bolts with the aluminum fittings. Has to do with an electrolytic pecking order of metals. In otherwords, if you join aluminum with iron or steel, there can be an electrolytic reaction between the 2 metals, causing deterioration of the lesser metal.
This might be the reason aluminum bolts are used in this case, because of the possible electrolytic reaction over a period of time. A reaction of this type could lead to a scaling weld where one or both of the metals will lose structure when trying to separate them. Can anyone chime in on this?
EDIT: I see this was addressed already today .......
This might be the reason aluminum bolts are used in this case, because of the possible electrolytic reaction over a period of time. A reaction of this type could lead to a scaling weld where one or both of the metals will lose structure when trying to separate them. Can anyone chime in on this?
EDIT: I see this was addressed already today .......
Last edited by IBLUBYU; 09-22-2010 at 01:10 PM.
Re: Valve cover leak...
Found this source for Aluminum SHCS's. The one needed for the breather cover is: M5-.80x16mm.
Metric Aluminum Socket Head cap Screws
Metric Aluminum Socket Head cap Screws
Re: Valve cover leak...
Found the info below researching suitable fasteners with aluminum earlier today with the goal to avoid and/or minimize galvanic corrosion:
You probably know that, were it not for its toxicity, the ideal fastener material is cadmium plated steel. (Note: Military uses these fastener types.) It is so close to aluminum on the galvanic scale that there is no galvanic corrosion, it is corrosion resistant itself, and it has great lubricity. Nonetheless, cadmium is a cumulative poison, should be reserved for only the most critical applications, and even then is being rapidly phased out.
The next best material is aluminum plating or coating, again because the galvanic potential is zero. You can investigate Ivadizing for vapor deposition of aluminum, or AlumiPlate for electroplating of aluminum. I fear that you may find the cost unacceptable though.
I am a bit confused by your reference to stainless steel brackets because these will (theoretically) cause the aluminum to galvanically corrode regardless of the fastener material. And, presumably being larger in surface area than the hardware, they will have a more powerful impact.
All of the above not withstanding, you didn't mention how the aluminum is corrosion proofed, so the question is a bit open. But I have seen stainless fasteners used on architectually anodized aluminum in outdoor exposure without any substantial problems. The zinc plating is not a good idea in my opinion because it will be short lived.
Ted Mooney, P.E.
finishing.com
Brick, New Jersey
You probably know that, were it not for its toxicity, the ideal fastener material is cadmium plated steel. (Note: Military uses these fastener types.) It is so close to aluminum on the galvanic scale that there is no galvanic corrosion, it is corrosion resistant itself, and it has great lubricity. Nonetheless, cadmium is a cumulative poison, should be reserved for only the most critical applications, and even then is being rapidly phased out.
The next best material is aluminum plating or coating, again because the galvanic potential is zero. You can investigate Ivadizing for vapor deposition of aluminum, or AlumiPlate for electroplating of aluminum. I fear that you may find the cost unacceptable though.
I am a bit confused by your reference to stainless steel brackets because these will (theoretically) cause the aluminum to galvanically corrode regardless of the fastener material. And, presumably being larger in surface area than the hardware, they will have a more powerful impact.
All of the above not withstanding, you didn't mention how the aluminum is corrosion proofed, so the question is a bit open. But I have seen stainless fasteners used on architectually anodized aluminum in outdoor exposure without any substantial problems. The zinc plating is not a good idea in my opinion because it will be short lived.
Ted Mooney, P.E.
finishing.com
Brick, New Jersey
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Re: Valve cover leak...
Originally Posted by dedwards0323
Something else I discovered when I looked more carefully at the SHCS's I picked up at CDJ parts counter earlier today. The replacement screws are M5-.80x18 SHCS's!
When I tried to replace the initial screw (doing these one at a time to minimize losing the new breather cover seal), that extra 2 mm length is enough to make the screw feel like it's either 'bottoming out' or possibly out of threads when tightened (as discussed earlier in this thread). So I stayed with the carbon steel screws from Lowe's. But will continue looking for screws that would be possibly better applicable for use with the valve covers to lessen the likelihood of any chemical corrosion down the road.
When I tried to replace the initial screw (doing these one at a time to minimize losing the new breather cover seal), that extra 2 mm length is enough to make the screw feel like it's either 'bottoming out' or possibly out of threads when tightened (as discussed earlier in this thread). So I stayed with the carbon steel screws from Lowe's. But will continue looking for screws that would be possibly better applicable for use with the valve covers to lessen the likelihood of any chemical corrosion down the road.
I ordered a bag of 100 stainless steel screws from McMaster Carr for $7.44.
I replaced the aluminum with the 300 series stainless and don't expect any problems from corrosion. I coated the threads will the same permatex I used on the covers.
