tinner

Well, I think I have unfortunately found my problem. I believe that my head/heads are cracked. When cold at idle my coolant looks fine, when it warms up to operating temperature, I have bubbles apparently pushing exhaust gas into the water jackets and causing an overheating issue that will not go away. I haven't yanked it apart yet, but I will over winter. I am probably picking up another set of #5 heads this week. I got it back with coolant issues...and I could never get it to run cool. Previous owner said that he may have run it hot.....I guess. Radiator hose was sucking in.

1970-W30

Could be just a bad head gasket, I had bubbles in the coolant, run a compression test first.....

tinner

I can do that before I commit to the heads, but if the head gaskets were bad....wouldn't it always show bubbles? Thanks

oldcutlass

You'll know for sure when you pull the heads. I had that problem on the old 330, it was just the shim gaskets. I did rebuild the heads anyway.

M-14

Sometimes coolant problems only show up at certain temps or pressures. I've seen water pumps leak bad when they are cold & under no pressure, but then seal up as the temp increases.

tinner

I had earlier put an air test on the cooling system, but it was not at operating temperature and it held plenty of pressure. Now it only apparently shows up when it warms up and things expand. When I got it back it would weep coolant between the head & block. I pulled it apart and put new head gaskets in it. The old ones were fine. I should have known better and had the heads checked back then. I guess I didn't realize I was in for such trouble as this thing only has a few hundred miles on it. It's frustrating.....When I had first owned the car, it was always dependable and never ran hot. The guy that had it rigged so much on it.