How to align the camshaft chain of Passat B5?
2 Answers
There is a notch on the inner edge of the camshaft sprocket, which should be aligned with the triangular mark on the last bearing cap. The marks for the intake and exhaust camshafts are the same. During installation, use a special tool to compress and position the chain tensioner. Install the exhaust camshaft and tensioner onto the cylinder head, and then install the exhaust camshaft. The following are common faults of the camshaft: 1. Abnormal wear: The camshaft is located at the end of the engine lubrication system, so the lubrication condition is not ideal. If the oil pump fails to provide sufficient oil pressure due to prolonged use, or if the lubrication passage is blocked preventing oil from reaching the camshaft, or if the bearing cap fastening bolts are overtightened preventing oil from entering the camshaft clearance, all these can cause abnormal wear of the camshaft. 2. Camshaft fracture: The camshaft may sometimes suffer severe failures such as fracture. Common causes include shattered or severely worn hydraulic lifters, severe lubrication failure, poor camshaft quality, and fractured camshaft timing gears. 3. Human-induced faults: In some cases, camshaft faults are caused by human factors, especially incorrect disassembly and assembly during engine maintenance. For example, forcibly striking the camshaft bearing cap with a hammer or prying with a screwdriver during disassembly, or incorrectly positioning the bearing cap during installation causing mismatch with the bearing seat, or overtightening the bearing cap fastening bolts.
When aligning the camshaft chain for the Passat B5, as an experienced mechanic, I emphasize the importance of precision in every step. First, stop the engine at the timing point and position the crankshaft at the top dead center (TDC). This requires using a special tool to secure the crankshaft pulley. Then, remove the cylinder head and locate the markings on the camshaft sprocket. Typically, the chain has colored links that must align with the points on the camshaft gear. Don’t forget to adjust the chain tensioner and ensure it’s properly seated, as a loose chain can cause valve collision. During the process, it’s best to use a digital angle gauge to measure the alignment, ensuring the error is within ±1 degree. I’ve encountered cases where customers misaligned it themselves, leading to oil burning issues, so always clean the work area before starting and apply anti-rust oil when installing a new chain. After completion, rotate the crankshaft to confirm the markings align properly and start the engine to check for smooth operation. Remember, details make the difference—this operation should take about half an hour if done skillfully.
