VW Passat 2004 and 2005 Inspection
The timing belt replacement interval is every 80,000 miles or else it can fail and damage the engine. When you change the timing belt you also have to change the water pump, timing belt idler pulley, and timing belt tensioner device. Unlike other types of engines, VW Passat TDI engines do not use index marks on their timing belts so you must use Volkwagen’s special tools to index the timing belt position.
The engine oil and filter should be changed every 10,000 miles if you are using synthetic engine oil.
VW Passat brake pads should be changed when the rotors are changed to make sure they bed correctly. They should be changed when the pads are low or the rotors are down to their wear limit.
The Passat TDI brake fluid should be changed every two years regardless of mileage. VW Passat should use only DOT 4 brake fluid because DOT 3 fluid has a lower boiling point temperature.
If the air conditioning is not cool you can have it recharged or leak tested. A common problem for a non functional AC is leaves blocking the AC condenser.
The engine air filter should be changed every 40,000 miles and the cabin dust and pollen air filter should be changed every 20,000 miles.
Some other things that aren’t part of a regular maintenance inspection include checking for rust. Rust can form along the bottom of the doors or the windshield trim. VW Passat tend to have water leaks due to clogged windshield drains or sunroof drains. This can cause mold in the interior or damage to the electrical grounds and computers under the front seats.
Mk4 VW Passat TDI also have problems with their balance shafts. The chain tensioner is a weak design and can break, causing engine starvation. The solution is to replace it with a gear drive balance shaft from a newer TDI. The balance shaft also drives the oil pump.
The front suspension control arms are straight out of an Audi A4 and as such, are expensive to replace. Creaking or clunking from the front suspension would be clues that the front suspension has bad bushings and needs replacement.
In conclusion, as long as you do these maintenance checks and fix any problems as they come up, the mk4 VW Passat TDI sold during 2004 and 2005 should be reliable and comfortable cars.
Ed is a frequent TDI owner who does DIY maintenance. You can learn more details and steps about how to do these maintenance procedures at http://www.myturbodiesel.com/1000q/b5/vw-passat-TDI-buying-guide.htm and ask any questions you may have in the VW TDI forum.