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1993 400e
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4 Posts
Discussion Starter #1
Hi, I have a 1993 400e with the 4.2 litter and I've come to a roadblock and don't know what to do. I stripped out a bolt hole when replacing the timing tensioner and I ended up drooling and re-threading it and I don't know if I made the hole a little bigger than need be, or what but I used a heli-coil and right now it's torqued to spec but it leaks major oil and currently is undrivable, so obviously it's not sitting flush. I've taken this apart 5 different times messed with it, put back together and failed every time.... What should I do? Fill that bolt hole in (w what) and start completely from scratch? I don't have the funds to take it in and have done so much to the lady with countless invested hours... any help is appreciated, as my mental state and back can't keep at it.
Thank you
David
 

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W124
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4,754 Posts
Just some thoughts: . Is the hole in the block or in the timing cover? If its in the timing cover then you might be better off just cutting your loses and sourcing another cover. Is the escaping oil just seeping out badly or is it under pressure? If its under pressure you really need to determine whether or not the hole is deep enough to thread in a thin plug and stil have enough thread left to insert the securing bolt for the tensioner. Good luck; that is a lousy problem to have.
 

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1993 400e
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4 Posts
Discussion Starter #3
Hi thanks for your response. The hole is the left hole that yo

Holds the double ended stud for the timing tensioner. It leaks- dumps rather- oil only when the car is running. I can't go much bigger bolt size wise due to the tensioners hole size
 

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2003 G500, 2000 SL500, 1995 E320 Cabriolet, 1980 TR8
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From your description, it sounds to me like the hole/thread you stripped out might have been a blind hole with a flat bottom and when you drilled it out to fit the heli-coil, you made it deeper/wider and hit an oil galley. If this is indeed the case, the only permanent solution that I know of is to replace the affected part because any type of plug will also block the oil galley and cause oil starvation.
 

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1993 400e
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4 Posts
Discussion Starter #6
Alright thank you I believe I understand what needs to be done. Next available free moment to tear it down I'll update with pictures as well as progress. Thank you all.
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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10,185 Posts
Have someone here pull that apart on a junker they have sitting around and see if it's a blind hole or goes through. Heli-coils are shite....should have use a real metal insert, like Time-sert or something similar. Post a pic of the exactly hole location.

Kevin
 

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You can have the hole welded closed and then redrilled and helicoiled. This will require some precision locating of the new hole so that everything lines up. The big question is whether or not this hole is in the timing case or the block itself.
 
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