Hi Dawson Galardo. Welcome to the forum. White smoke is typical of a leaking head gasket or cracked cylinder head. In this case, the coolant is still pressurized when it is hot after the engine is stopped, and that pressure forces it into one of the cylinders where it is burned when you restart it.
Cost of repair is no easier to estimate than a visit to your doctor. It depends on what is needed and what extra things the mechanic plans on doing. The cheapest estimate may not be the best choice. That mechanic may just slide a new gasket in place. His low estimate may be due to his desire to outbid his competitors. The head must be checked for flatness. If more than about.002" of warpage exists, the head must be straightened or replaced. If it is cracked, it must also be replaced. Surface prep is important so the new gasket has the proper surface finish to bite into to help it seal.
To increase the quality of the repair, some mechanics will also remove and resurface the valves. This takes a couple of extra hours, but based on the relatively low miles, this may not be a good value for your engine. Most mechanics will likely recommend replacing the timing belt. Add in the cost of an oil change after the rest of the service work is completed.
To make estimating somewhat consistent between shops, most of them will use a "flat rate guide" that spells out the hours and tenths of an hour each procedure should take. They will add up those times and multiply it by their shop's hourly rate. If, due to experience or having invested in a lot of specialty tools, the mechanic gets the job done faster, he makes more dollars per hour, but you pay the same amount. If, due to unforeseen problems, or carelessness that causes him to have to do something over, he loses money but you still pay the same amount. Here again, the shop with the lowest hourly charge is not always a bargain.
Friday, May 21st, 2010 AT 1:57 PM