S600 W220 Broken Cylinder Headbolt?
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2001 MERCEDES S600
S600 W220 Broken Cylinder Headbolt?
I broke the #2 cylinder headbolt on drivers side while torquing the cylinder head. What are my options? Can I just leave it in since all the other 13 bolts are good. Is it possible to try to use an extractor to remove it? Will the broken bolt cause a problem with performance of the car?
Champouelle1
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Mercedes
I broke the #2 cylinder headbolt on drivers side while torquing the cylinder head. What are my options? Can I just leave it in since all the other 13 bolts are good. Is it possible to try to use an extractor to remove it? Will the broken bolt cause a problem with performance of the car?
Champouelle1
Champouelle1
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From: Houston
001 s600, 94 sl600
BROKEN HEAD BOLT
The broken off bolt MUST BE REPLACED or the head gasket will leak in that area--leading to $$$$$$ to fix.
Does your engine have 'internal socket head bolts' requiring a TORX 'allen key' inserted into the bolt head or the newer style that require only a standard metric socket.. Those that require use of a 'Torx allen key' that INSERTs INTO the bolt head MUST BE REPLACED.Those bolts are prone to breaking off where the head and shaft join AND are much too prone to corrosion--leading to bolt failure and head gasket leaks.
Your Dealer might free-replace all your head bolts if they are the 'socket head' ones. There were both Technical Service Bulletins and MB programs to replace all the socket heads , including removing cylinder heads etc.
Does your engine have 'internal socket head bolts' requiring a TORX 'allen key' inserted into the bolt head or the newer style that require only a standard metric socket.. Those that require use of a 'Torx allen key' that INSERTs INTO the bolt head MUST BE REPLACED.Those bolts are prone to breaking off where the head and shaft join AND are much too prone to corrosion--leading to bolt failure and head gasket leaks.
Your Dealer might free-replace all your head bolts if they are the 'socket head' ones. There were both Technical Service Bulletins and MB programs to replace all the socket heads , including removing cylinder heads etc.
Last edited by Kebowers47; Sep 5, 2020 at 10:11 AM. Reason: misspelling
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From: Montreal, Quebec
2009 E350 4M Avantgarde;mistress 2002 S600; wife 2014 C300 4M
Torquing V12 head bolts is not for the faint of heart!!
Man, don't mess with this. The broken bolt will on the V12 hit the cam shaft, and then things get totally messy.
Did you measure the the head bolts for stretch before re installation as per WIS?????
Deadly if you didn't.......change them all!!
Man, don't mess with this. The broken bolt will on the V12 hit the cam shaft, and then things get totally messy.
Did you measure the the head bolts for stretch before re installation as per WIS?????
Deadly if you didn't.......change them all!!
Last edited by kraut56; Sep 5, 2020 at 06:45 PM.
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2001 MERCEDES S600
Lower cylinder head #2 broken headbolt
The broken headbolt is the lower one. By the exhaust, not the one inside up next to the camshaft inside the valve cover gasket. Can I just leave it. I dont want to take off the head again.?
Champouelle1@yahoo.com
Champouelle1@yahoo.com
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2001 MERCEDES S600
cylinder head lower #2 broken headbolt
yes indeed Tusabes, it's the lower #2 headbolt that I broke. It's the one next to the exhaust. The one inside the valve cover next to the camshaft is fine. I cant imagine taking the head off again, the oil cooler and other stuff. Can the broken bolt be extracted so deep inside the engine block? Without taking the head off again?
champouelle1
champouelle1
Last edited by champouelle1; Sep 8, 2020 at 09:23 AM.
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2001 MERCEDES S600
Lower cylinder head #2 broken headbolt
Torquing V12 head bolts is not for the faint of heart!!
Man, don't mess with this. The broken bolt will on the V12 hit the cam shaft, and then things get totally messy.
Did you measure the the head bolts for stretch before re installation as per WIS?????
Deadly if you didn't.......change them all!!
Man, don't mess with this. The broken bolt will on the V12 hit the cam shaft, and then things get totally messy.
Did you measure the the head bolts for stretch before re installation as per WIS?????
Deadly if you didn't.......change them all!!
Champouelle1
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From: Montreal, Quebec
2009 E350 4M Avantgarde;mistress 2002 S600; wife 2014 C300 4M
You did not answer my first question: DID YOU MEASURE ALL BOLTS AS PER WIS before re-installion?
If you didn't, you have to replace them all, as one broke during torquing.
No wishful thinking here.
If you didn't, you have to replace them all, as one broke during torquing.
No wishful thinking here.
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From: Houston
001 s600, 94 sl600
IMHO--- a broken cylinder head bolt must be replaced to prevent head gasket failure. The aluminum alloy cylinder head is quite flexible and head gaskets have to seal perfectly all the time. What happens with uneven tightening of head bolts is uneven sealing pressure on the gasket and leaks will develop. Depending on where the leak develops,it can be a nuisance, or catastrophic. Yes, it is a PITA to remove the cylinder head to remove the broken bolt---BUT head warping and leaks are a certainty. IF you wish to have a durable engine, there really is no option--the broken head bolt MUST BE REPLACED.
The aluminum alloy cylinder block is ALSO flexible and a broken head bolt will allow the cylinders next to the missing bolt to flex to out-of-round and cause piston scuffing and cylinder wall. damage. The cylinder bores are finished with a 'torque plate' bolted onto the block to simulate the clamping pressures and distortion resulting from head bolt tension. This ensures the cylinders are perfectly round during operation
Will the head gasket fail and leak if the engine is operated with the broken head bolt? Probably. Will it run for a while if driven easy? Maybe These head bolts are tightened to the 'stretching point' and are permanently stretched by the proper tightening. These bolts ARE NOT REUSABLE. IF your engine has the old style Internal-TORX socket head, they must be replaced in any case because they will fail in service right where the stem flares out to make the socket head.
The aluminum alloy cylinder block is ALSO flexible and a broken head bolt will allow the cylinders next to the missing bolt to flex to out-of-round and cause piston scuffing and cylinder wall. damage. The cylinder bores are finished with a 'torque plate' bolted onto the block to simulate the clamping pressures and distortion resulting from head bolt tension. This ensures the cylinders are perfectly round during operation
Will the head gasket fail and leak if the engine is operated with the broken head bolt? Probably. Will it run for a while if driven easy? Maybe These head bolts are tightened to the 'stretching point' and are permanently stretched by the proper tightening. These bolts ARE NOT REUSABLE. IF your engine has the old style Internal-TORX socket head, they must be replaced in any case because they will fail in service right where the stem flares out to make the socket head.
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From: Montreal, Quebec
2009 E350 4M Avantgarde;mistress 2002 S600; wife 2014 C300 4M
Well, when I did my M137 the WIS clearly stated to measure the bolts, and gave very specific measures and tolerances.
Everyone of my bolts was in the "like new" values, so I followed the "reuse" instruction.
I believe the headbolt problem started on the M275 engine, when higher power and boost was implemented.
Anyways, I did my engine in 2014, and it has run just fine since then (must have done something right).
BTW: These bolts are torqued to stretch, NOT to yield! (on the M137).
But yes he is in trouble, and has to re-do it!
Everyone of my bolts was in the "like new" values, so I followed the "reuse" instruction.
I believe the headbolt problem started on the M275 engine, when higher power and boost was implemented.
Anyways, I did my engine in 2014, and it has run just fine since then (must have done something right).
BTW: These bolts are torqued to stretch, NOT to yield! (on the M137).
But yes he is in trouble, and has to re-do it!
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2001 MERCEDES S600
The broken off bolt MUST BE REPLACED or the head gasket will leak in that area--leading to $$$$$$ to fix.
Does your engine have 'internal socket head bolts' requiring a TORX 'allen key' inserted into the bolt head or the newer style that require only a standard metric socket.. Those that require use of a 'Torx allen key' that INSERTs INTO the bolt head MUST BE REPLACED.Those bolts are prone to breaking off where the head and shaft join AND are much too prone to corrosion--leading to bolt failure and head gasket leaks.
Your Dealer might free-replace all your head bolts if they are the 'socket head' ones. There were both Technical Service Bulletins and MB programs to replace all the socket heads , including removing cylinder heads etc.
Does your engine have 'internal socket head bolts' requiring a TORX 'allen key' inserted into the bolt head or the newer style that require only a standard metric socket.. Those that require use of a 'Torx allen key' that INSERTs INTO the bolt head MUST BE REPLACED.Those bolts are prone to breaking off where the head and shaft join AND are much too prone to corrosion--leading to bolt failure and head gasket leaks.
Your Dealer might free-replace all your head bolts if they are the 'socket head' ones. There were both Technical Service Bulletins and MB programs to replace all the socket heads , including removing cylinder heads etc.
Champouelle1@yahoo.com
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2001 MERCEDES S600
Broken headbolt S600. Overtorqueing
also, the extractor drill bit is too short. That bolt is way inside the block. How can it be taken out.? I cant find a long reversible left hand drill bit over 10 inches long and an extractor bit over 10 inches long. So I am Screwed either way. Not too many options. Can I pack it with JB weld to prevent it from leaking exhaust? It's the headbolt by the exhaust not the one inside the valve cover next to the cam.
Champouelle1
Champouelle1
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From: Montreal, Quebec
2009 E350 4M Avantgarde;mistress 2002 S600; wife 2014 C300 4M
The deadbolts were the Torx type. I visually checked them. They were all the same length. It was from overtorqueing that the one broke. WIS had called for 20Nm. I went to 80Nm reading the Paperwork that came with the head gaskets. Only one broke like I said. The #2 next to the exhaust not the one by camshaft. I dont want to take a chance of drilling to extract the broken bolt. I also cant redo the job taking off the 2 heads off again. I am using someone else's garage, I need to move the car this weekend. So if it leaks I am screwed. Can I fill up the hole with JB WELD and put the bolt in to prevent exhaust leak?
Champouelle1@yahoo.com
Champouelle1@yahoo.com
Did you use WIS?
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2001 MERCEDES S600
Hi there WallyP, if I decide to weld a left handed drill bit to a steel rod and another steel rod to an extractor bit. Will the broken bolt come out because of the previous torque of almost 80Nm? Also is there any danger that I might accidently drill into the engine block causing more damage? Bu nevertheless, it sounds like a great idea to fabricate a 2 dril bits. I will try to locate a welder to do it for me. I will keep everyone updated of my progress.
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2001 MERCEDES S600
Hi thre Kraut56, I did use WIS, but guess what. They never said those bolts should never be reused specially the Torx type head bolts that are in my 2001 S600. They just say to measure them to see if they can be reused. They should have recommended them to be replaced period, as I found out they had a recall for the Torx type bolts. I just put them next to each other and see if they were damaged or stretched. I visually compared them to one another to see any of them were longer than the other.
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From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
If the welder gets the drill bit attached to the extension perfectly straight, it will make this possible. In order to guide the drill bit straight to the center of the bolt, you can try using some hard tape, such as clear packing tape, carefully wrapped around the extension just above the drill bit, and again just where the rod enters the hole. Make the tape thickness just large enough to put the bit in the center of the hole, but not so large that the friction against the hole will melt or damage the tape. Make sure that the tape is applied so that friction against the hole tries to wrap it more tightly, not where the friction tries to unwrap the tape. Applying light oil to the tape would help.
If you are really lucky, the drill bit will enter the bolt and then stick, and slow, careful turning will back it out of the hole. I think that the fact that you simply pulled the bolt in two with excessive torque is better than the bolt seizing in the threads would have been.
All this being said, you may still be screwed. You over-torqued every bolt. If one or more of the bolts fail when the block and heads expand from the heat of normal operation, you may get significant engine damage. You might be driving a grenade with a loose pin...
If you are really lucky, the drill bit will enter the bolt and then stick, and slow, careful turning will back it out of the hole. I think that the fact that you simply pulled the bolt in two with excessive torque is better than the bolt seizing in the threads would have been.
All this being said, you may still be screwed. You over-torqued every bolt. If one or more of the bolts fail when the block and heads expand from the heat of normal operation, you may get significant engine damage. You might be driving a grenade with a loose pin...
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From: Houston
001 s600, 94 sl600
MBZ is very specific DO NOT REUSE these defective internal TORX socket head bolts. They are failing right where the bolt head forging upset begins due to inadequate strength AND excessive shank corrosion from the coolant. IF you succeed in removing the broken one, cross your fingers, hold your tongue in your teeth, and remove and replace one bolt at a time, but postpone final tightening until all new bolts are ready for final tightening. With great luck you will be lucky and get them all out without having to remove the heads. IF another one breaks, drill and remove it and keep on trying, or just do the PITA and remove the heads. DO NOT RUN THE ENGINE until all the defective and overstressed bolts are replaced. You should discuss this with your Dealer---they may 'free issue' all the new bolts and gaskets. It is REMOTELY possible they will trailer the car in and do all the work under the recall and Service bulletin, or share the cost with you if you offer to 'make up' the pay to the Tech so they are made whole for the work (they do not get adequate pay hours for this work and Service Manager will greatly appreciate the cost-sharing.
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From: Houston
001 s600, 94 sl600
You DO NOT NEED a 'left-hand drill bit' I strongly suggest a long shank right-hand bit of high quality (pro factory robotic quality), with the centering and straightness confirmed and corrected /fixed by CNC machining or grinding to say 0.010" smaller than the measured bolt hole diameter in the head. This straight, perfectly centered, close fit drill assembly should drill straight and centered, I would want at least 0.050 of 'good metal' left in the bolt shank hole walls for the 'easy out' to have a good bite. I would then chill the bolt with refrigerant spray, chilling it for a minute or so just prior to trying to back it out, You want the thread area of the bolt cold but the shank warming up. The welder must have tempered/stress relieved the weld affected hot zone to avoid brittleness.
Consult with a Drill Manufacture about the best bit point and sharpening angles. A high tech specialty machine shop will not be cheap, likely a couple of hundred dollars, but this is not the place to dicker on price. You MUST get absolutely straight, centered, 'running fit' in the hole in the head. Be sure and leave enough good metal in the drilled hole walls so the 'easy-out' will not bulge the bolt shank
Consult with a Drill Manufacture about the best bit point and sharpening angles. A high tech specialty machine shop will not be cheap, likely a couple of hundred dollars, but this is not the place to dicker on price. You MUST get absolutely straight, centered, 'running fit' in the hole in the head. Be sure and leave enough good metal in the drilled hole walls so the 'easy-out' will not bulge the bolt shank
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From: Montreal, Quebec
2009 E350 4M Avantgarde;mistress 2002 S600; wife 2014 C300 4M
Any update?
I think the easiest way is to just pull that head off and start again.
And, where did you get instructions with the head gaskets?
Not MB.
Good luck!
I think the easiest way is to just pull that head off and start again.
And, where did you get instructions with the head gaskets?
Not MB.
Good luck!
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Joined: Apr 2019
Posts: 428
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From: Houston
001 s600, 94 sl600
In order to facilitate bolt-by-bolt replacement, I recommend you hit fairly hard straight down on the head of each old bolt to 'loosen'any 'stiction.' This helps 'breakaway' of tight bolts. If the old bolts break off, you have no choice but to drill out enough to use an 'easy-out' to remove the broken ones. Otherwise, you must remove the engine to get enough 'clearance' to lift the head over bolt stubs sticking up into the cylinder head. If the bolts break at or down in the block that does not create a clearance issue in removing the cylinder head..
May you have good success in this unfortunate task that resulted from bad information -- MBZ does not issue new WIS versions for every Service Bulletin or Special Instructions, or Special Warranty Campaigns. They presume 'Authorized Service Personnel' remain current on ALL INFORMATION they publish.
May you have good success in this unfortunate task that resulted from bad information -- MBZ does not issue new WIS versions for every Service Bulletin or Special Instructions, or Special Warranty Campaigns. They presume 'Authorized Service Personnel' remain current on ALL INFORMATION they publish.
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2001 MERCEDES S600
Yes indeed Gentlemen, I decided to take the left cylinder head off again and replace the broken head bolt, hopefully it comes out with the extractor. I am also hoping that the other head bolts don't break during the removal process as I am going to replace all 28 of them. I will contact Mercedes Dealer in Greensboro N.C. to see if they will give me the new replacement head bolts. I will keep you guys posted of my progress.
