11-10-2004, 12:34 AM
First off, Glad to hear you got it fixed!
As For the water-jacket Block-off's , had similar problem on a Vette, that wasn't leaking so much as you'd notice it, but it wouldn't "Burp" the system and it had an air bubble in The water pump...
Consequently the temp gauge did "Excursions" From 160 to 240 and back again in about 1 minute oscillations. and it acted the reverse of an overheat...let it idle forever and it sat on 170...drive it (with real good airflow over it) and it would rise and fall!
After much head scratching, replacement of the thermostat, flushes and back flushes Sealer In case of a pinhole leak gulping air, Sealer on the manifold bolts, I resigned myself to the fact I must have a cracked or warped manifold or heads...blowing hot gasses into the cooling system, after pulling the manifold I found it "Ate away" almost beyond repair at the front right and left rear block-off ports! (See Photo)
What made it so intriguing was that it was not using any noticeable water, nor did it actually overheat (except for the very first time the problem showed up..well above 260 degrees) and it did not "Act" like a hot car...no ping, heater working fine, nothing to indicate the engine was hot..
Anyway, I was able to repair the manifold with high temp "Orange" sealer...and so far it seems to be doing fine...
Just thought I'd pass it along...
So you can have a leak and never see it!