Hello,
My car has been loosing coolant every 100 miles. It all started last year summer. The mechanic said it had a bad water pump and rediator, and so both were replaced. The carworked fine for 6 months. Then, one day I decided to drain and replace the coolant myself. Soon after that, the car has been loosing collant again. There is no water acuumulation underneath the car. Is the the water pump/rediator again or something else?
It is either leaking or being ingested by the engine, those are the only options. If it isn’t leaking on the ground, you should have your head gasket evaluated.
Yes, by all means get a cooling system pressure test done. It will reveal where there is a leak.