2000 Volkswagen Jetta overheating?
I have a 2000 VW Jetta 2.0 that has started overheating. About 2 months ago the temperature light came on but the car was not overheating at this point. I did some research and found out that the light will come on if the coolant is low in the reservoir. I added G12 antifreeze to it and it was fine for a week then i had to continue to add to it every few days. As of today, it is now overheating. The reservoir now boils and it seems to be shooting steam/coolant from around the thermostat housing area. The coolant level in the reservoir goes up and down. How can I tell if this is the thermostat or water pump that's to blame or something else?
Sounds like you've got air in your lines. I had the same problem. Does it really start boiling about thirty seconds after you turn the car off? You know, you might have a leak around the thermostat which let the air get in. Fix the leak and burp the cooling system.
When the car overheats, do you get cabin heat? If not, its the water pump. VW uses a plastic impeller water pump which has a tendency to separate from the metal shaft. Water pump failures are fairly common.
You haven't exceeded the antifreeze mix (max 50/50%) have you? too strong a mix causes overheating. plus it sounds like you have a leak near the thermo housing.