[Othen]

Originally Posted by Laird Scooby

I'm going to be the voice of dissent on this one Alan. Looking at your picture from a few days ago, #1 combustion chamber to the water channel above it in the pic nearest the thermostat, it can be seen there is corrosion in that area on both the gasket and the head - chances are this was where the combustion gases were getting into the cooling system.

You will almost certainly find similar markings on the block in the same area. If the head (above the gasket) has eroded as the photo seems to show, this means the gasket can also lift up, allowing water to pass under the gasket and erode the block in the same area.

Have you retorqued the head since the rebuild? As in got the engine hot and retorqued by cracking each head bolt 1/4 turn then retightening to spec? Might pay to double-check to see what Haynes suggets in this respect, you may have to get it hot and alow to cool before retorquing, i can't remember and not fully awake yet. You may find this solves the problem with no further investigation needed.

It could also be related to the head bolts, i believe they can be re-used once on red blocks, if they've been in and out like a fiddlers elbow they really need replacing though. Out of interest, did you run a tap through the head bolt holes or otherwise ensure (by running each bolt in and out of its hole) they were free to turn easily all the way in and out?

Something in the back of my mind also wonders if the bubbles in the tank were just an air lock shifting gradually and bringing residual bubbles of CO - being heavier than air, if it was trapped in the coolant in the block, it's possible there was still some lurking in the system. Until it was heated up, the gas would have remained compressed under the water in the block then expanded with heat into a big enough bubble to force their way up and out.

Thanks Dave,

I'll let you know what happens.

Stay alert,

Alan

PS. The head bolts can be used 5 times on red block engines.