Coolant leaking from studs in head

[phaetn]

I've been chasing a coolant burning issue for quite a while. I've tried various gaskets - MLS and paper - but that's not my issue now.

I'm using a stud kit that has worked previously. The first time I used the studs I tapped the threads in the block as per instructions in the kit (10mm 1.25 pitch). I used some black sealant at the bottom of the threads. This made it difficult to take them out later (had to double nut them).

Earlier this year, I used copper gasket spray at the bottom of the threads as part of putting on an MLS gasket. This made them easier to get the out over the weekend and didn't pose any issue that I could tell.

Over the weekend I tapped the threads again as part of trying a paper gasket again. Then I installed the studs again, but didn't use any product on the threads. I buttoned everything back up but before I started the car I did a coolant pressure test. Now, for the first time ever, I've had coolant leaking out the top of the studs at the nuts. Very weird (saw coolant filling the spark plug recesses). Freaked me right out and was coming out multiple studs.

So my question is a simple one: do the threads in the block for the head bolts/studs go into a coolant passage at the bottom? Or is this just a leak at the paper gasket itself and it's working its way up the studs? I'm not sure about how the block is manufactured...

Thanks for any help!

Cheers,
phaetn

[aj81spider]

Yes some do.

[phaetn]

Thanks for the reply, aj81spider.

I confirmed the same with Allison's today, from whom I had bought the stud kit previously. Indeed, the channel does go into a coolant passage. I don't have the instructions any more and missed that important step of putting on a sealant. I bought a Permatex thread sealant today that should do the trick.

The good news is I should be able to do it one stud at a time and not have to take off the whole head again and therefore apply another head gasket. I wasn't looking forward to doing that yet again...

Thanks again and cheers,
phaetn

[wetminkey]

You'll like the Permatex thread sealants. I've used them for years, in all types of engines, without failure.
Great stuff, and it will not make future disassembly difficult,...