Valve cover gaskets aren't that big a deal. A dealership selling used cars would have taken care of this to maintain their reputation if it was deemed necessary. Rather than trying to squeeze them for a few dollars, you might have better luck agreeing to buy the car if they agree to replace the gaskets. Also, at the dealership I used to work for, every engine got steam-cleaned before it had all the other maintenance done. If that was done to this one, a leaking valve cover should be easy to spot. If the engine was not cleaned, your mechanic could have been seeing months of built up residue with road dirt sticking to it. That will happen to almost all engines over time and is hardly a reason to avoid a car.
In the past, replacing valve cover gaskets was a one or two-hour job if you took your time. Today, some manufacturers made it uncommonly difficult by planting a lot of parts over them. Taking all that extra stuff apart is what is so time-consuming.
Be aware too that some engines use reusable valve cover gaskets. When they start leaking on my '88 Grand Caravan 3.0L, there are just two bolts to turn a half turn tighter. If the valve covers are removed, the old rubber gaskets are meant to be reused.
Most newer engines now use gasket sealer out of a tube. That material can make it a little more difficult to pry the covers loose, and it takes a while to remove the old material, but those are less likely to develop leaks.
Wednesday, March 4th, 2015 AT 4:34 PM