Partly Cloudy Continental

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Q.

I have a 1972 Lincoln Continental Mark IV 460 V8 7.5L. When I start vehicle each day a cloud of smoke rises from drivers side exhaust manifold and quickly dissipates. However, car idles rough thereafter. If I let vehicle sit for a couple hours and restart the smoke is less.

A.

When you claim, “a cloud of smoke rises from drivers side exhaust manifold“ do you actually mean from the exhaust manifold or out the drivers side exhaust pipe? The exhaust manifold itself should not smoke, although if the valve covers are loose or the valve cover gaskets are bad. This permits oil to seep out onto the exhaust manifold as the car is sitting, but once the car starts the oil is quickly burned off. Later on if the car sits for shorter time it has less oil to burn off so less smoke. If you pull your valve covers also check for the flatness of the gasket surface on the valve cover. If the valve cover has been over torqued down the surface can become warped and permit oil to seep out.

A cloud out the exhaust pipe at start up can be a few things, and it’s best to try and determine what kind of cloud you have.

A white cloud that smalls like car exhaust is often simply condensation in the exhaust system and will dissipate after driving a few miles.

A bluish cloud that has an oily smell is often an indication of worn valve seals; as the car sits oil in the rocker arm area drains down along the valve stems and pools on top of the valves if closed or drains into the cylinder if the valve is open. Once the engine is started the oil is burned off.

A greyish cloud that has a heavy fuel smell can indicate an engine that needed to be turned over several times to be started and is burning off the excess fuel. Or a carburetor that is adjusted too rich or a choke setting that is incorrect.

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