I have coolant spraying from a core plug at the rear of the left head on a '71 Pontiac 400 cu in. The engine is installed in the car, leaving a gap of maybe 5-6 inches before the firewall. I've never replaced a core plug before - any tips on how to remove the existing plug and install a new one without removing the engine?

I have coolant spraying from a core plug at the rear of the left head on a '71 Pontiac 400 cu in. The engine is installed in the car, leaving a gap of maybe 5-6 inches before the firewall. I've never replaced a core plug before - any tips on how to remove the existing plug and install a new one without removing the engine?

[78 GHOST]

I'd pull the engine.

[quicksilver97ta]

Sorry to hear about the leak. There is probly a special removal tool but you can simply punch a hole in the middle and then pry it out. Don't scratch the hole in the head as this may provide a place for the new plug to leak. First choice for a replacement would be another brass/metal plug but due to the inconveinent location you might have to go with a rubber one temporarily (as in emergency). They have a nut in the middle of them which you tighten to expand the plug. Once again, very temporary.
Hope that helps, maybe someone has a tech tip to install a brass freeze plug with limited space.

[quicksilver97ta]

What do you think about dropping the crossmember and letting the tranny pull down on the rear of the engine to try to get at it from the bottom? Still not enough room? Too far to reach over the tranny? I'm sure every chasis is a little different, f-bods might be the most challenging.

[oldman]

I had the same thing happen to me. I put
a screwdriver in th eold freeze plug and
pulled it out. As said before, don't scratch
the sides of the hole. I took a measurement
between 2 bolt holes on the front of the
right head, then driiled a 3/8" thick plate
with a 13/32" diameter drill in 2 places
using the measurement bewteen the holes.
Use (2) 3/8" bolts about 2 1/2" long, put
them through the holes on the plate and thread them into the head. Put the freeze plug in place and put a large socket inside the freeze plug.Tighten up the 3/8" bolts evenly and it will push the freeze plug right into place.
You will also have to get shorter bolts as it longer bolts will start to bottom out in the head.

[cblandin]

oldman - that is an excellent tip...will be filing that one away for sure.

[quicksilver97ta]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by CAB:
oldman - that is an excellent tip...will be filing that one away for sure. <HR></BLOCKQUOTE>


I agree, excellent tip.