[Hearts88]

Hi, I have a 99 Chev lumina with the 3.8L engine.
On the weekend we were out late at night and had the heater on and it was blowing cold air. Despite the temp gage being right in the middle. (normal)
Then today we noticed the temp gage going up very high.
The temp was going back down to normal but would go back up again shortly after going to normal. So I am guessing that the thermostat is opening.


When I got home and popped the hood... the passengers side fan was running and the drivers side was not. Is this normal? Does it only come on if the temp goes even higher?

Anyway, the cold air blowing when the temp is normal tells me that there is Air in the system... is that right?

2nd, Should I do a complete flush of the system and replace my thermostat?

If so, can someone explain how do flush the system.

Thanks.
Hearts88