Modern cars have modern oil systems. These systems are designed to operate with less drag on the engine to increase fuel efficiency. This is done with lighter oils, smaller oil passages and tighter bearing tolerances.
Modern oil pumps are designed to vary the output volume and pressure. This is in contrast to older pumps that had a fixed displacement for all conditions. Older systems produce more than enough pressure, and the excess oil pressure can be bled off by a regulator and pumped back into the pan. The excess pressure is wasted energy and results in drag on the engine.
Older engines could deal with a restricted passage or pick-up without damaging the engine. Newer engines can’t cope with even the smallest restriction due to smaller passages and variable valve timing actuators that use oil pressure to control the camshaft angle.
In these systems, debris can make it past the filter (if it is in bypass) and can block passages. This can cause damage to the bearing surfaces of the crankshaft and camshaft. Also, debris can block passages in the variable valve timing actuators.
When removing old gaskets, there are two things to avoid. First, you want to avoid any of the material from entering the engine. Second, you do not want to damage the sealing surfaces. On modern engines with aluminum castings, a metal scrapper can do a lot of damage.
New Strategies
There are chemical gasket removers on the market designed to soften baked-on materials from components. These products can soften a gasket and release it from the engine so larger pieces can be removed. Larger pieces mean there is less of a chance a piece of gasket can find its way into the oil system.
There are two types of gasket removers on the market. The first type is designed to remove gasket material, cements and dressings. The other type is designed to remove silicone gasket materials like RTV.
After spraying or brushing on the gasket remover, wait 20-30 minutes or the time period recommended on the package. The silicone will become softer and more pliable. It will also release the gasket from the component. The strength of the silicone’s bond will also greatly reduce, making it much easier to remove.
Avoid using abrasive discs and sandpaper. In the past two years, GM, Subaru, Chrysler and other manufacturers have issued TSBs warning technicians not to use abrasive materials to clean gasket surfaces. These TSBs recommend using a chemical gasket remover and a plastic chisel to remove the old gasket in large pieces.
