Coolant Flush and Fill:
This is probably the most covert killer of head gaskets in the auto repair industry today. Today’s high tech aluminum engines need someone with a thorough knowledge of how the newer cooling systems operate in order to properly bleed the cooling system and prevent hot spots before the engine is started. I hate to say it but it’s probably better to never change your coolant than to have an inexperienced technician perform the service. Yes, old acidic coolant can ruin your gaskets as well as corrode your radiator and heater core but improper bleeding techniques will surely take a substantial amount of life out of your head gaskets and will more than likely ruin them. The process is simple to understand. If any air is left in the heads before the engine is started that area of the head will expand very rapidly due to heat from the combustion process.
When the metal expands it presses down very hard on the area of the head gasket right under the hot spot in the head. This is like putting the head gasket in a vise and clamping it as hard as you can. It gets squished hard! When the cooling system finally bleeds itself (as the thermostat opens) the hot spots cool down and contract. This leaves a head gasket with not enough clamping pressure on it. It is doomed to failure. Probably not right away though. In fact, it will probably not go out completely until months later when a connection between the improper flush job and the blown head gasket is not obvious. This is not only true for flush jobs but for any job that involves draining a portion of your coolant. The bottom line is proper cooling system bleeding takes time. More time than an average technician can afford to spend for $20.00 labor.
Most flush jobs take 20 minutes to flush and over a half hour to bleed. That’s nearly $60.00 in labor alone plus the price of the coolant. Since a vast majority of the cars on the road today have this type of engine how can you expect to get a proper job on your cooling system for the $40.00 special most low ballers advertise? Do you think the technician might feel pressure to cut corners to speed up the process? Do you think management cares? Especially considering the blown head gasket will likely not be traced to the flush job? In my opinion this is sabotage!