1998 V70 non turbo 78k. After we flushed the engine coolant and cleaned the engine with simple green the car now has the check engine light on. I covered everything I thought I should with plastic bags when washing off the engine. The car started right up but did hesitate about 1 minute after running and eventually shut off. It would restart after sitting and now runs fine. I also twisted the battary post connections but did not remove them from the post to remove corrosion. What could I have done wrong? Is there a bleeder screw for the coolant system? Is there a way to reset check engine light without loosing my radio or screwing anything up? I used 70% Prestone yellow antifreeze to 30% distilled water for coolant. Is this ok for this engine or does this car use another type of coolant? Thanks for your help.