First check the timing belt. The replacement cost can be up to $1000. The 2005, 2006 VW Jetta TDI timing belt replacement interval is every 80,000 miles. You must change it or else it could fail and cause damage to the cylinder head or pistons. When you change the timing belt, gudu make sure the mechanic also changes the water pump, rollers, and timing belt self tensioner. You must use VW’s timing belt tools or else the camshaft timing will be off. VW Jetta TDI engines don’t have paint index marks for replacing the belt so the timing belt tools are required.

Engine oil analysis shows that the engine oil is good for 10,000 miles. When you change it, make sure to use only diesel rated synthetic engine oil. Also change the oil filter with an OEM part or equivalent. hobbijaim

The brakes are what stop the car so make sure they work. Check the brake pad wear to make sure the brake pads are usable. The brake rotors should not be gouges or deep marks in them. The brake fluid must also be changed every 2 years regardless of how many miles you drive. Only use DOT 4 specification brake fluid and not DOT 3 specification brake fluid because DOT 3 fluid has a lower boiling point. Never used silicone based brake fluid. receptek

A common problem on early mk5 VW Jetta TDI is a bad air conditioning compressor. The clutch is internal to the compressor so if you don’t have cool air or have cool air only after 15 minutes, the compressor could need replacement or the system may need a charge. when you test drive the car, make sure the AC works well and blows cold.

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.

Check for water ingress. There was a recall over the sunroof drains where they clogged and let the interior flood. This can cause rust or mold in the interior. Water corrosion can also damage the grounds and wiring.

If the car has high mileage, olcsobbszerviz check the struts by pressing a corner of the car down. If the motion is not dampened well the car could need new struts.

If you have a DSG transmission, check for clunking of the transmission. This can be a defective flywheel that is failing.

Many Jetta TDI from 2005-2006 have had bad camshaft wear. If you remove the valve cover and see worn lobes on the camshaft, the camshaft, lifters, and camshaft bearings must be replaced or else it can break and cause severe damage to the engine.

Finally, make sure the car has adequate power. A poorly maintained TDI engine can run poorly and give low power if it has broken vacuum lines or is poorly adjusted. If it runs well,  you can expect many years of good service.