Trax

I have a 1969 400 BB that is leaking from the thermostat gasket. One of the bolts for the water outlet is obviously stripped and was considering trying to repair with "helicoil" thread repair. I have never used this product and don't know anything about it. My questions are:
!. Is this a good acceptable repair?
2. Can this repair be made in place or does the manifold need to be removed from the engine?

Olds64

Heli-coiling the threads is a permanent repair. It'd probably be easier to do it with the intake manifold on the bench vs. installed on the engine.

oldcutlass

It can be done with the manifold in place, use a thread sealer on both the helicoil and the bolt.

OLDSter Ralph

Be sure to get the right length Heli-coil. Too long is not good.
Make sure the "tail" is 1 to 1 1/2 threads below the gasket surface.
Read the instructions and use sealer as suggested by Oldcutlass.

oldolds88

after Heli coil mine, I used studs in place of the bolts. Another fix is keen serts, i like those better than the coils'.

davek1661

A friend used helicoils back in the day, and they came out next time he had to pull the bolt, so using a stud is probably a great idea. I have a Suzuki with an aluminum oil pan, previous owner used a helicoil when the oil drain plug threads stripped, and when I pulled the drain plug, the helicoil came out with it. Drain plug is steel, so someone probably over tightened it. I replaced the oil pan. When I have a stripped hole, I generally just drill it out and tap a new thread one size larger, but a cast iron manifold might be hard to tap. If it doesn't work out, you can replace the manifold. It's only money after all!

Sugar Bear

Yes it is an acceptable repair. It should be able to be easily done in place. If you've drilled a hole and tapped threads you've mostly done this and didn't know it. It is pretty easy just drill straight!!!

Trax

Thanks for the advice guys. Seems a lot easier and cheaper than purchasing a new $500 manifold.