A blown head gasket allows coolant to seep into the combustion area where it is converted to steam and smoke. The resulting white plume of smoke from the tail pipe is a tell-tale sign your head gasket is blown. A mechanic knows this job is a costly one, and it affects the value of your car substantially. Trading in a car with a blown head gasket requires a little negotiation skills and knowledge to back up your trade-in offer.
Assess the value of your vehicle at KBB.com. On the home page, select the vehicle type, then the make, model and year. Enter your zip code when prompted. Select "trade-in value."
Locate the trade-in value on the following page and then select all applicable features your vehicle possesses, such as air conditioning, power steering and all custom parts and modifications. Click submit.
Find the "Fair" condition price on the following page.
Take the car to the dealership. Inform the dealer of the vehicle's condition. Allow an inspection. Offer 10 to 20 percent below the Blue Book "fair" condition trade-in value. Go as low as 40 percent below the "fair" condition value on your trade deal.
