The 2.5 VW 5 cylinder engine was essentially the replacement for the older 2.0 liter normally aspirated base model engine. It has a 20 valve cylinder head, with variable valve timing. The 5 cylinder configuraton is known for better torque and smoother revving operation than a 4 cylinder. The engine ratio of bore to stroke is undersquare, meaning a smaller bore and a longer stroke (82.5mm x 92.8mm), which also means more torque than horsepower. The first iteration, from January 2005 (BGP/BGQ/BPR/BPS), produced 148 horsepower and 166 ft/lbs or torque. Starting with the 2008 model year of Jetta and Rabbit, (CBT/CBU) the power increased to 168 hp. and 176 ft/lbs. The Beetle did not get the high power engine until the change to the A5 Beetle in 2012, at which time the engine also became available in the Passat. A distinct difference in the top engine cover makes identifying the difference between the early and late versions easy.
This 2.5 VW 5 cylinder engine did not appear in the Audi line in the U.S., although in other countries, the 2.5 is used as a turbocharged high-performance engine in a few Audis. These 2.5 5 cylinder engines are not descendants of the 1980’s Audi 5 cylinder engine as is the Eurovan engine from 1993. Those engines had a timing belt on the pulley end of the motor, and this 2.5 VW 5 cylinder engine has a timing chain system on the transmission end. The castings for both the block and head are very different from the Audi 5 cylinder from last century.
The timing chain system consists of an upper and lower roller type chains with tensioners and guides. A significant point is that the intake camshaft gear has a very low included angle, meaning that the chain only contacts the intake cam gear by 8 to 9 teeth, which represents around 70 degrees of the 360 total. Most cam gears are driven by at least 90 degrees. This leaves this 5 cylinder engine more prone to skipping timing chain teeth than other motors when one fails to change the oil often enough.
A vacuum pump is used to provide consistent high vacuum for the brake booster. It is located on the transmission end of the cylinder head, whereas the 1980’s Audi engine had a different type of vacuum pump located on the side of the head in some models. The vacuum pump is a notorious source of engine oil leakage, often causing a donkey-sized puddle of oil. Pump removal for replacement or reseal is relatively easy on an engine with a manual transmission, but takes many times longer with an automatic transmission.