I have a 4 cyl 1.8 sentra with 102,000 miles. When I was driving the other day the temp gauge shot up to H and dropped to normal. This happened several times. With that, I’m not getting any heat in the car.
I put a new water pump in and the T-Stat has been changed twice (just in case). I flushed the radiator and flows fine. I flushed the engine and the flow seemed a little slow coming out but it did.Same with the heater core.
Any suggestions would be great!
You most likely have air in your cooling system, that needs to be bled out.
BC.