My 1966 Chevy Impala convertible is leaking coolant from the rear breather under higher rpm's . I replaced the intake gaskets, made sure all was level, (Edelbrock intake and 4bbl Edelbrock carb) and it still leaks. No coolant in the oil or filter. Spark plugs are dry. I did a coolant pressure test and it stayed at 19 lbs overnight. Any thoughts before I tear it down?

 

Bad head gasket would be my guess. You MIGHT be able to seal it with K&N block sealer, but you have to have clear water, not coolant for it to work. After it seals you can add your antifreeze back.

 

When did this start? Has the intake manifold been replaced, before this issue?

 

oilcanhenry …
Thank You! I also am leaning towards head gasket or cracked head....

 

kevinkpk Long story on this car. It was burning oil so I had a shop overhaul it....or so they said. Then for various reasons it sat for six years with new oil in it. The intake is the one that has always been on it. The Edelbrock intake has the back two coolant ports blocked.....I spoke with a rebuilder with 30 years experience also a machine shop who has been doing engine work for 50 years....and they both said they had never heard of this.....