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Discussion Starter #1
Hi all.

Managed to pull the rear head off my v6 cos I couldnt get 4 of the exhaust studs back in.

I managed to put studs in 3 of the holes I was having trouble with, but one is definitely cross threaded. Put a stud which went in abuot 3-4mm, but I noticed it was at about a 90° angle, and when I removed it I found tiny bits of swarf in the hole.

I've never had to sort out anything like this before, and I know I will have to get someone else to have a look at this, but as far as I can see, I have two options, to try and get the hole re-tapped, or to get it helicoiled.

I was thinking of trying a re-tap first, then if it totally goes pearshaped, then getting it helicoiled. Does this sound like the right approach? Can't find much info- search on helicoil only returned one thread!

Also I when I pulled the head off, each of the cylinders had a little brown liquid in them. Only thing I can think of is that that bank might have been running overfuelled because I ran it without the exhaust connected, and I pretty much removed the head the previous sunday, but couldnt quite get it off without an assistant, so only actually pulled it yesterday, so a bit of oil and water may have made its way in and made this nasty looking mixture.

 

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I think the brown liquid will be rusty water, my engine was full of it, its slowly been cleaned out over the last few years since its last re-build. Perhaps some just leaked in when you took the head off.

I would say re-tap it and do it up carefully
 

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Discussion Starter #3 (Edited)
I'm not sure if its just coolant though, because the system was drained when I took the front head off, and I wouldn't expect fresh water to go so brown so quickly. Should've actually inspected it, but was in a real rush. I don't think (hope it won't be) anything major

Thanks for the advice. I thought I had try and ask someone who has done this before as I haven't got a clue when it comes to fixing dodgy threads.

Edit: Changed would to wouldn't
 

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Defo try to retap first. The threads are pretty coarse so if you`ve only knacked the first little bit you will be ok.

A retap in this case isn`t so mauch a retap as a clean-up and realignment of the existing thread - I don`t mean drill out and redo.

I second the rusty water opinion. Water can go red very quickly when in contact with steel and the contaminants in the soot will only help speed that up (says my elementary 'O' level chemistry:) )
 

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yeah as has been said try running a tap thru it first, if its only a few threads that have been damaged you may be lucky. if that fails i would probably fit a helicoil (if you can be bothered with the little extra work)
 
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