I just changed the water pump and timing belt and put a new Thermostat, I drove to my parents about 50 miles away, i pulled off freeway and it started getting hot I had to pull over to let it cool off, pulled thermostat the next morning drove back to my house, on the way back about 30-35 miles on the freeway same thing started getting hot and had to pull over, pulled water pump back out appears to be in good condition?? anyone have any ideas on this situation for this car?? I heard you could get air in the system but i left running when i added coolant with the cap off??
Car runs fine until you go 30 miles and it gets hot. on 2001 Volkswagen Passat
Water pump impeller failure was common, air should have purged out of the system after your drive if you had the heater turned to full hot you should have had full coolant flow. I wonder if you could have a blown or mildly blown head gasket? The most accurate way to test for a blown head gasket on a gasoline engine is to test for the presence of carbon monoxide in the cooling system. Snap-On, Matco (part # CO 2000), and Napa sell a tool to check to carry out this test. Another link to a supplier of this tool is http://www.etoolcart.com/combustion-leak-detector-lis75500.aspx. Carbon Monoxide is only present if there is a blown head gasket or cracked cylinder head. http://www.arrowheadradiator.com/head_gasket_or_combustion_leak_test.htm I think the napa part number 700-1006. http://www.blockchek.com/instructions.htm . Signs of a blown head gasket are coolant loss (frequently have to top up the coolant level of the engine without seeing an obvious leak), experiencing over heating or rough engine running or the presence of white sweet smelling steam from the exhaust. A badly blown head gasket may allow engine coolant and oil to mix.
I will have to get that tool, the problem did not occur until directly after changing the pump and timing belt, would this of happened before I changed the pump and timing belt? Before I changed everything it was fine, it is at 77000 miles so I wanted to get the water pump, timing belt and the other belts changed for preventative maintenance.
It has been a long time since this post but I had the same thing happen. Car running fine replaced water pump and timing belt at 102K. Within 1 week it overheated. It was while air conditioning running in stop and go traffic. Mechanic who did the work 1) replaced fan 2) replaced the other fan 3) thermastat. I no longer turn on the air but if the car is run on the interstate at high speed for any real length of time (30-45 minutes) it will start over heating.