My oil pressure light has been flickering after about 20 minutes of driving only at idle. After reading some info from another thread, I checked to see if my oil cooler was getting warm, and it was cool to the touch with the car warmed up and running. The oil pan was hot to the touch. Is the oil thermostat something that cleaning could help? eEuroparts sells just the spring, would that be all I need to replace or do I need the whole kit?