I have an Nissan A15 engine in my blueline Carpet cleaner. It has been shutting down because of engine coolant temperature I think. Ive replaced thermostats, engine coolant, blown out radiator, changed oil and filter recently, oil level is full, Ive bled air out of system, replace coolant sensor. I have no idea why it continues to shut down after running on high, medium and low speed. My indicator light says oil pressure, or engine coolant temperature is high. Any help? Allen Graham 559 221-0715