Heat Exchanger Barrel Nut removal
 

Greetings =

It seems that when I last installed the heat exchangers on my 2.2S motor, one of the exhaust head studs was backing out during the tightening process. Now I don't have enough depth available for the allen head wrench to engage (about 1/16") for removal.

Anyone have any ideas for getting this sucker off without damaging the head or exchangers? There doesn't seem to be any rust issues - the other five nuts came off without a problem.

Thanks!!

Hopefully the stud isn't frozen in the head. Get a torx 6 or 12 point bit that is just a bit larger than the hex socket (I can't remember if it is an 8mm or 10mm hex head) and tap it into the hex socket then you should be able to unscrew the barrel nut.

Thanks, Kurt, but I guess I wasn't clear. The allen head socket part of the barrel nut is fine, it's just filled to nearly the top with the exhaust head stud. Picture trying to remove a nut without the flats - that's what I am facing.

It's too tight in there to get vise grips or channel locks on the nut, and I am afraid of damaging something if I try to gain purchase on the barrel nut with a cold chisel so that it can be backed off.

I guess what I'm really looking for are some successful BTDT stories.

Well if you still have 1/16" of depth and you think it will back out, How about JB welding the allen wrench onto the barrel nut?

Studs rarely back out during the tightening process; the mechanics of the setup is too inefficient. It was more likely backed out before, when the system was taken apart. There is almost nothing in the way of common tools that you can insert up through the access tube that is strong/rough/hard enough to gain purchase. Getting in from the side with tools like visegrips or pliers is also very difficult. You could use an abrasive cut off wheel to trim the end of your hex key bit to ensure it is as sharp as possible and with a small grinding stone (cone or point type) hollow grind the end of the bit to get get the drive hex down as far as possible into the nut. Another possible option is to find a nut splitter that will fit in there around the nut; drive it's chisel in to gain purchase and then get on the splittler with a lever like tool to loosen the nut. However, I would suggest your best option now is to arc weld something to the barrel nut like a long bolt with the head protruding downward and outside of the heat exchanger or a short rod projecting sideways from the barrel bolt. Next time you'll know to check the stud length and slip a washer under those barrel nuts to ensure a bit more hex length for the hex bit to register against. Good luck, Jim

I had to use the old chisel technique due to rust and had no issues. Just create a groove with a cold chisel then turn the nut by hitting it in the groove at an angle with the chisel and hammer.

Thanks, all.

I'll give a small cold chisel a careful try, then go for the JB Weld if that fails. Hopefully, I will know just what went crunch in the case by the end of the weekend.