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My 454 engine is running hot and has rust colored exhaust when first started. what is the cause?

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If the engine is "raw" water cooled than it is possible that the cooling passages in the manifolds, goose necks and even the block may be blocked by rust scale. Removing the goose neck from the exhaust manifold will show you if there is a rust problem developing. If the scale is in the block than it might be too late. If its "Fresh" water cooled than the same still pretains to the Exhaust manifolds and goose necks as they are raw water cooled, if there is scale in the block than it is usualy caused by not using enough anti-freeze in the heat exchanger and there will also be rust in there as well. Keep in mind that the cooling water discharges out the exhaust at the goose neck, so remove them when the boat is out of the water or if the exhaust is not below the water line.

Posted on Oct 01, 2009


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