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Q: I have a 1965 Thunderbird with a 390 engine. The mechanic is somewhat baffled. The PVC valve and hoses have been replaced. Everyth

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My car has 70000 miles.
My car has an automatic transmission.

Hi There, Unfortunately, part of your question was cut off when it came to our queue, so I will answer the best I can as it looks like your question relates to the PCV (Positive Crankcase Ventilation) valve. The PCV system is relatively simple. An inlet hose connects to a filtered air source. This is used to supply clean air that is drawn through the engine. Most of the time this air is supplied through the engine air filter. On a few designs there is a separate inlet filter that cleans the incoming air for the PCV system only. This filtered air flows through the engine, picking up fumes and vapors. The air exits through another hose, connected to manifold vacuum. The flow of air draws fumes from the crankcase and burns them harmlessly in the engine. This also creates a slight vacuum, relieving any pressure that may build. Negative pressure helps to prevent oil leaks and oil consumption by the engine. The PCV valve also helps regulate the amount of air flow, which helps prevent oil being drawn out of the engine. When the PCV valve is not working correctly, this will cause an imbalance in air flow and vacuum resulting in poor running conditions and rough idle or stalling. I would recommend having an expert from YourMechanic come to your location to diagnose and replace your PCV valve.

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