Question1996 jetta overheats in the first 10 minutes of driving in any conditions,can a stuck thermastat be the problem and how about the water pump how do i test it?
Answer
Jetta_thermostat
With the car cold, start it. Immediately, open the radiator cap so you can see the coolant level, look inside, observe the coolant should stay relatively still. After a reasonable warm-up period (5-10 minutes) the thermostat should open(you cannot directly see this), however, a good indication is you should be able to see the coolant moving inside the radiator. If not, the thermostat is likely bad.
As far as the water pump, you can't easily test it, however it normally goes bad by:
1) Leaking, which is noticeable by the coolant under the car and the level in the radiator getting low or ...
2) By the bearings going out, in which case you will hear it grinding, or it will completely lockup and the belt will soon be destroyed(within minutes).
From your symptoms, I believe it's your thermostat.
Good luck.
