Whats a smog pump? My dad says its fixing to go out, how can i remedie this? on 1990 Dodge Dakota

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I'm trying to buy this truck. I drove it it runs good got ac n radio but my dad says the smog pumps going out, where is it how expensive is it to fix.
(1) Answer
Smog pump is an auxiliary emissions device. If your state/county has emissions inspections, you will certainly need to keep it. It pumps air into the exhaust to help with the oxidation of exhaust before exiting the vehicle. Its usually belt driven and if your Dad says it failing, then more than likely the bearings are failing, which will require pump replacement. Don't neglect it, because if its driven by the serpentine belt, and the pump locks up, it will break the serpentine belt and that will cause loss of steering, engine over heat and dead battery (since those systems rely on the serpentine belt as well)