Is this a common 3rd gen problem? It was leaking when I bought the car, so I bought a new GM waterneck from the dealer and a Fel-Pro reusable gasket. I installed the new parts and it still leaked. I pulled it all apart and slathered on some waterpump gasket goop and put it all back together again. I let the stuff dry for two days. Guess what, still leaks. There's no noticable scratches or gouges in the mating surface of the waterneck or intake manifold. Is there something I should be doing different? It's a 305 TPI with the long waterneck. Can I use an aftermarket o-ring waterneck? All of the o-ring one's I've seen are short necks, not long like mine. Please help.

 

sometimes the waterneck mating surface also warps.... you can try to get a flatedge and tell.. but im sure its more of a PITA with TPI then carb or TBI...

if its warped, i usually end up sanding it down even again with some 600 grit or so and a sanding block..

sounds kinda crude, but done right, it can straighen up both the waterneck and the manifold thermostat housing more then enough to seal...

since you probly cant do that, id suggest cleaning off both mating surfaces as well as you can.. you want them a lil rough, and getting a thick paper gasket.... spread a good amount of permatex RTV (blue or black.. and not the gel looking other stuff, the permatex stuff) on both sides of the gasket.... then lay the other one down... make it snug but not tight... then once the RTV sets, make it tight.

this only works about 3 out of 5 times, but if you cant/dont want to pull off the manifold to square it up (assuming thats your problem) then its worth a shot...

 

ive had this problem quite a bit in th past and mainly with the LG4 and L69 intakes yeah, LG4 were installed in alot more vehicles than just the camaros and firebirds, they wer ealso instaleld in 80-up caprices el caminos, malibus, montes, etc,. all are the aluminum 4 bbl 305's

i clena it all up and put new gakset on and that usually fixes the leak problem, and if a new neck didnt fix it then there must be warpage with the intake, you might have to rmeov eintake and have the mounting flange machined flat

the o ring types are even more problematic with leakage. dont go that way

maybe double gasket ?

good luck