Coolant system pressure test results

["cruznmd" <racuti1@xxxx>]

A key "moment of truth" during the re-assembly of my engine is the 
cooling system pressure test.

Following Dave Stragand's advice, I hooked up a small pump the the 
overflow bottle to pressurize the system. The first thing I note is 
that I do not have the right bottle. This was a recent discovery. 
Mine appears to be out of a late 80's/early 90's Mercedes Benz.

I went one extra step, spraying a soapy water solution around key 
points (head gasket mating areas, water pump connections). I also 
removed the thermostat before sealing the system because it's my 
understanding that with the thermostat closed (cold) I'd only be 
testing one side of the cooling system. This test is also supposed to 
help me determine if I shifted a piston liner, ruining the seal 
underneath.

The results?
1. I had 3 leaks on the water pump due to crappy clamps. Fixed.

2. One -tiny- leak at a head mating surface in the "valley" on the 
driver side. It leaked at a rate of 3 bubbles per second, I was able 
to tighten it down to a rate of 1 bubble per 2 or 3 seconds. Perhaps 
when the metal expands, and contracts and I perform the re-tightening 
procedure, it will stop entirely.

3. One leak on the passenger side head towards the front of the car. 
Even smaller than the other one, I watched it actually stop leaking 
completely on it's own.

4. The worst leaks were from micro fractures in the overflow bottle. 
I sprayed it down and it bubbles in several places on the top.

I was unable to hear -any- hissing from inside the engine that would 
indicate an internal leak. It takes a considerable amount of time for 
the pressure to bleed off through the cracks in the overflow bottle.
The rate of leakage from the bottle is consistent with the time it 
takes for the pressure to drop to zero.

That is, the bottle doesn't just give 1 or 2 bubbles while the 
pressure drops quickly because of another leak elsewhere.
I realize that this isn't very scientific but I don't know what else 
to do. I think I've done ok. I welcome any suggestions.

I know I have to replace the coolant bottle. I saw one on Ebay that 
was pretty reasonable. The guy only wanted $400.00....;-)