rotten bolt is stuck in the engine cover
 

Hi, I have the e70 diesel and am trying to replace the glow plugs.
But I got stuck at the early stage of this. A rotten bolt is stuck in the engine cover and prevent me to remove the cover alone with the sound proofing foam block. Anyone can tell me some idea how to deal with this? Thanks.

The 1st picture with part 9 shows the bolt.
The 2nd picture shows my car's actual bolt. The inner hex edges are gone.
The 3rd picture shows the engine bay, where I tried to stick a hex head and turn it but it's not loosing the bolt.

You need to clean the dirt out first so the hex or torx wrench can fit in properly.

I did some. You can see the bolt head is almost like a ring now. I don't think clean it out would help much anyway.

Drill it.

Drill the head off with a bit larger than the shank of the bolt. Once the cover is off there should be enough bolt protruding you can get a pliers on it....

Yes. Clean it out with a sharp pick. You can literally see how much crap is in there.

I cleaned mine out and hammered in a slightly bigger bit and that was enough to remove it. This happens because the plastic partitions leak and you should check your #5 and 6 injector because the same water leak soaks the spongey insulation. It's wise to get rid of that too, since it holds water and promotes corrosion.

From the 3rd picture, you can see the space there is quite limited. I can only insert something less than 3 inches there. Do you guys have to take out the cover of brake oil and a bunch of things above it first? I just feel that way is too much work.

I'm thinking I have to drill a hole from the side and cut the cover around the bolt as a solution...

I also found some bit that is specific for Damaged Screw Extractor. But I have to stick a screw driver straight above it. But then I have to remove the bar and cover above that area. No idea how much work that is and can't find some instructions for removing it.

I used a 3/8in ratchet with a hey bit “socket”. This gave me the clearance I needed and allowed me to put down force on the ratchet/socket. But you could use a 3/8in breaker bar if yu can get a hex/torx bit socket to jam into what is left of the head of the bolt

Funf Dreisig

After you clean it out, sometimes using one of those bit kits with a massive selection of 4,5point torx, hex, blah blah bits, you might find ONE that can hammer into it and get enough grip.