Was just at the Napa trying to pick up a helicoil kit to fix my intake manifold on my 394 that's dripping coolant out of the front most passenger side stud.

The guy at the counter told me I needed the exact thread and pitch size for the kit. I did bring the stud with me but he couldn't tell me sizing.

Anyone have this info or know where I could get it? Looked in the service manual but can't find.

Much appreciate any help I can get on this.

Thanks

Justin

 

Seriously????

Go back to NAPA with the stud. Find a nut from their hardware drawers that fits it. NOW you know the thread size.

 

It always amazes me the ineptitude and laziness of parts counter people.

 

Sadly, it DOESN'T amaze me...

 

WHOA. It doesn't usually amaze me, but in this case, I think I'm kind of overwhelmed.

Not only do they have drawers of nuts and bolts to compare it to, they usually have some sort of a display item with little embedded nuts and bolts, which you can thread your onto to see what size it is.

That's actually bad enough that I'd look at the guy's name tag when I got back there and have a talk with the manager about him.

- Eric

 

Yeah, I was about to add that every NAPA I've ever been in has that thread gauge display, as does every Home Depot and Lowes. It usually looks something like this:

 

That's the exact one I was thinking of, Joe!

I don't think I've been a NAPA that didn't have one.

- Eric

 

Yeah it was kind of a weird experience. I had the stud with me and he didn't suggest that. I thought maybe he thought it was going to be an odd size. Whatever.

 

I have bolt size and pitch gauge at the house that I use. They can be bought at any bolt house for a few bucks.

 

Based on the comments here, I went to a different part store. They had buckets of fasteners and I was able to match it up - was a very common 3/8" -16.

They don't sell the Helicoil brand but provided "Fix-a-thread" kits made in Australia. They were also on sale for $14.99 vs. $65 (Canadian) for the Helicoil kit. Seems like a decent quality kit.

This is my first time attempting re-threading anything, so thanks everyone for pointing out that it should be a simple thing to at least select the right product. No thanks to the lazy Muppet at Napa.

 

Wow, fail.

It can't be metric, so that leaves MAYBE 4 choices
3/8-16 NC, 3/8-24 NF, or maybe possibly 5/16 NC or NF.

 

Here's another hint. The insertion tool used to screw the helicoil into the newly-tapped hole has exactly the same thread as the threads you are trying to repair. Simply match the insertion tool thread with the bolt/stud thread.

 

Back to the original post. Why is coolant leaking from the hole in the head where the stud goes? Admittedly, I know nothing about the 394 heads, so do these studs go into a coolant passage in the head? I'm confused....