They hop in the car
The engine appeared to be running perfectly, so they decided to test drive the car for a short while. After driving the car for a couple of minutes, the person in the passenger seat said, “It’s all good, man. The car doesn’t really care.”
He then asked, “What happens if we do this repeatedly for a few hours and it doesn’t blow up?” His friend responded pretty bluntly, saying it would be proof that “you can use WD-40 as engine oil.”