Coolant Loss !!!!

[Hummie2]

Joe...

There was a post here that I don't see anymore( I guess it was deleted) and it made more sense about what is happening than anything else. It was about a cracked or porous intake port runner in the head to a water jacket. Coolant would find its way to the inlet valve then into the cylinder and out the exhaust. Compression would would not get back into the coolant because the inlet valve is closed then, so combustion gases won't be present in the coolant. Here is what you do to check:

1- get the engine hot (fully up to temp) then stop it.

2- pull #2 sparkplug, pull the valvecover for #2 cyl and turn the motor till intake and exhaust valves are in overlap (both valves partially open)then pressurise the cooling system to about 15lbs

3- wait and watch (you should see coolant in cyl with a borescope- wait long enough it will fill up and run out the plug hole!)

coolant is finding its way into #2, but compression is not going back into the cooling system. That is why the insulator broke on the origional plug (from water in the cyl) and why the new plug stays clean. The same could hold true for an exhaust runner also, but I would suspect an intlet leak because of the plug problem.

Don