cooling or exhaust issue?

[rondahart]

Don,
I acquired my 1972 Ericson29 two years ago. I am not aware of the maintenance history of her A4. She starts and runs effortlessly. While allowing her to reach operating temp, I noticed the temp gauge was pegged at "0". After approx. 8 minutes of idling, slight whisps of smoke eminated from the vic. of the exhaust outlet flange, and the exhaust manifold just seemed to be hotter than I recall. I set off to investigate the exhaust flange gasket, clean the connection at the temp sender, and check out the themostat. My results: the gasket was replaced since it appeared to be flaking and brittle, the connector at the temp sender was frozen to the nut holding it and the post on the temp sender it is attached to rotates freely, and the thermostat is AWOL. I have robust water flow exiting exhaust, still have whisps of smoke at the exhaust outlet, and have a sinking feeling that my exhaust manifold is going to melt down after 5-10 minutes of operation at idle speed. I promptly shut down the engine in less than 10 minutes the two times I've run the engine since noticing my problem. Troubleshooting the temp gauge notwithstanding, what about the missing thermostat and smoke? I haven't been able to see the source of smoke, it just seems to flow out the vic. of the exhaust and increases in rate the longer she runs (only after about 8 or 9 minutes of running).

regards, Ron

[Don Moyer]

Ron,

Your symptoms are very consistent with the upper exhaust flange bolt leaking a bit of water out onto the hot exhaust flange (and pipe) and turning to steam. This condition is most prevalent in later manifolds where the upper bolts came very close to the water jacket in the manifold. You may be able to remove the bolt and seal it with JB Weld. It will also help to use a flat washer under the head of the bolt instead of the locking washer.

Don

[rondahart]

Thanks Don,

With my thermostat removed, am I to assume that my block is getting adequate water flow. I have not yet had opportunity to isolated reason for no reading at my temp gauge.

Ron

[Don Moyer]

Ron,

Short answer: no.

With the thermostat removed in a late model engine, the water is free to either enter through the "T" fitting in the center of the water jacket side plate to cool the engine or to pass around the block through the bypass loop, in which case it will not cool the engine.

Don