Do you have any issues cold starting your car?
When I had a blown coolant innter o-ring, not only did I fail the "bubble test" mentioned in this thread, but the car was hard to start initially.
There will be some coolant in the combustion chamber and cause a slow start. After blipping the throttle a few times, it would clear out the coolant and idle would be normal.
At that time, I noticed massive bubbling in the overflow tank.

Hope you find the root cause and fix the problem.

 

hahahaha.....if everything else fail... time for rebuilt. and replace radiator, rad hoses, etc.

 

AJatx, I have had some problems with bad starts and bad idle just after starting, especially after not driving it for a few days...

Thanks for the advice everyone. I'm pretty confident now that it is a blown coolant seal after all. Yep, it looks like rebuild time!!! And since I'll be using it on the track more often next year, am planning to get all hard and soft seals replaced while it's all in peices. Should be a fun little project. A new clutch and lighter flywheel will be nice too . It's a damn shame I won't be able to make any progress until after my thesis is due though...

Karack, I agree with you, I am not confident in doing a rebuild on my own, but I am pretty confident with being able to at least get it into a short block. Believe me, the crack in the goose neck was not obvious at all, and was clearly not the cause of the coolant problems either.

Cheers,
- TT

 

After reading this thread, I have been having the same problem with my car. Ever day after I drive my car if I check the coolant level at the cap and the coolant is low and if I check my overflow tank it is over full and if I take the coolant from the overflow tank and put it into the filler neck then everything is at the right level. My car passed the bubble test. I can run my car everyday and the coolant buzzer never goes off, but if I run the heater when I stop and sit at a light the add coolant buzzer will go off, but never at any point does my car get hot. If the buzzer sounds I can rev the engine and the buzzer will go off for about 30 sec and then come back on.

My pressure cap I bought from Autozone and is about a year old and I have been using a drilled thermostat so all that is left is a ring (I live in AZ). I replaced the line between the filler neck and the overflow bottle when I replaced most all of the vaccum lines with silicone.

After reading this I guess my problem is a pin hole air leak some where or possible my pressure cap.