2007 E63 Head Gasket Went Bye Bye
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Joined: May 2013
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2007 E63
statpkt, Restating here what was in the earlier thread...Engine design "apparently" relies on thread sealant in the block threads to keep coolant out of the bolt/ head area. One Jaguar site stated that the bolt heads themselves were a final barrier (my words) to coolant into the valve train area. And merc63 told us of ?sealant? used by his race shop under the bolt heads. Of course? the coolant loss phenom on C63 is due to coolant entering the combustion chamber via the relaxed or blown head gasket , probably after the bolt head is snapped off.
Even though I say "crevice corrosion" I keep vascillating. Your bolts look like coolant "could" have gone up the whole shafts, but something triggered the runaway corrosion on some? To my knowledge proper coolant is not affected by temp gradients, and I do not know how/if fresh coolant separates so that water alone is somehow at the top of those corroded headbolts.
I ramble so some expert will chime in, hopefully. All this is moot except for curiosity as these cars age and MB corporate shrugs the problem off as routine maintenance. ( Yeah, my lowly , running 26 year old GM iron block has never been apart)
Neither has the SR20 in the Nissan.
Even though I say "crevice corrosion" I keep vascillating. Your bolts look like coolant "could" have gone up the whole shafts, but something triggered the runaway corrosion on some? To my knowledge proper coolant is not affected by temp gradients, and I do not know how/if fresh coolant separates so that water alone is somehow at the top of those corroded headbolts.
I ramble so some expert will chime in, hopefully. All this is moot except for curiosity as these cars age and MB corporate shrugs the problem off as routine maintenance. ( Yeah, my lowly , running 26 year old GM iron block has never been apart)
Neither has the SR20 in the Nissan.I have no idea if the previous owner used MB coolant or MB approved coolant. Unless you were the original owner I suspect it will be hard to tell.
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From: DFW
2007 E 63
I feel like this may be a really dumb question, which should be my biggest warning, but I'll ask anyway. If the head bolts seem to be a point of failure, why not just replace them before they fail?
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From: San Diego/San Francisco
AMG GLC63. Audi R8
A valid question esp if you come from the world of US OHV push rod V8's. The head bolts on the 63 engine are torque to yield and many are located under the cams. To pull the cams, you need a special cam lock tool from MBZ. Because you have to remove all the head bolts at the same time, the head gasket is compromised. That means you have to pull the intake and exhaust manifolds as well as the heads. The lifter are also faulty and need to be replaced. Its very parts and labor intensive. At most dealers, only a few of the techs are qualified to do this work.
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From: Battle Ground WA
C63AMG, NIssan NX2000, Pontiac Fiero GT
Many knowledgeable people have discussed the headbolt issue, but we are no further in understanding the problem. IMO this is due to lack of stats and lack of access to failed headbolts. Many factors could be at work in the failures.
Another member has stated that (?all?) headbolts in M 156 engines sit in coolant (as opposed to more typical engine design of some or none, where coolant leakage to the head surface must get past the thread sealant to interact with the headbolts shaft and head). The first series of pictures of failed headbolts ( C63 forum)showed corrosion residue only under the bolt heads. Then we saw statepkt's which are heavily corroded throughout.
Another thread talks about coolant "adjustment packets" (?wiki") which are inserted in the coolant tanks (elsewhere?), but C 63 member stated none in his coolant tank. Finally , we note the galvanize coating on the MB improved replacement head bolt, a change from previous versions.
There is evidence of perhaps two headbolt suppliers, derived from logo impressions on the heads. The mystery continues.
Another member has stated that (?all?) headbolts in M 156 engines sit in coolant (as opposed to more typical engine design of some or none, where coolant leakage to the head surface must get past the thread sealant to interact with the headbolts shaft and head). The first series of pictures of failed headbolts ( C63 forum)showed corrosion residue only under the bolt heads. Then we saw statepkt's which are heavily corroded throughout.
Another thread talks about coolant "adjustment packets" (?wiki") which are inserted in the coolant tanks (elsewhere?), but C 63 member stated none in his coolant tank. Finally , we note the galvanize coating on the MB improved replacement head bolt, a change from previous versions.
There is evidence of perhaps two headbolt suppliers, derived from logo impressions on the heads. The mystery continues.
Last edited by motoman; Nov 15, 2013 at 11:15 AM. Reason: name and spelling
Junior Member
Joined: Apr 2013
Posts: 44
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From: DFW
2007 E 63
A valid question esp if you come from the world of US OHV push rod V8's. The head bolts on the 63 engine are torque to yield and many are located under the cams. To pull the cams, you need a special cam lock tool from MBZ. Because you have to remove all the head bolts at the same time, the head gasket is compromised. That means you have to pull the intake and exhaust manifolds as well as the heads. The lifter are also faulty and need to be replaced. Its very parts and labor intensive. At most dealers, only a few of the techs are qualified to do this work.
I understand engineers can't precisely design everything and some items get overlooked and you can't control your suppliers but seems like a fairly obvious flaw. Hindsight is to blame I guess.
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07 E63
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2014 BMW M235i
What do you mean, can you elaborate on this? And I assume that with any engine there are inherent issues. The balance shaft issue with the M272 / idle gear issue with the M273 didn't prevent me from eventually buying an E550 and I've been fine. My fear is just getting into an AMG with 80k on the clock after selling mine which has been relatively problem free and getting stuck with 5k plus in head bolt repairs since it's not an easily diagnosed/rectified issue.
