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2.0T Timing Chain Tensioner Failure

2.0T BELT DRIVEN Timing Chain Tensioner Failure (B**)

Gear case (3)The early version of the 2.0T engine is in VW and Audi vehicles from 2005.5 to 2008 or 2009 depending on the model. These are belt driven motors and for some strange fortune of mnemonics, the USA version engine codes start with a “B” and are three characters long (BPY, BPJ, BWE). So think B for Timing Belt. The exhaust camshaft is driven by a timing belt on the pulley end of the motor, which also drives the water pump. The intake camshaft is driven using a chain with a tensioner between the two camshafts on the transmission end of the cylinder head. That tensioner, particularly the upper plastic shoe, is a possible failure item. It is quite likely that the failure rate is a consequence the 10,000 mile oil change interval, and especially for those who drive even further without changing the engine oil.

In this earlier 2.0T design, the cam chain tensioner is not adjustable, i.e.; it does not rise and fall to change intake cam timing like its earlier 1.8T cousin in production from 1996 through 2005.5. The intake camshaft has an adjustable timing gear that operates electro-hydraulically. A solenoid directs engine oil pressure to the intake cam gear to advance or retard the intake cam timing as required. The exhaust cam timing is not adjustable.

2.0T CHAIN DRIVEN Timing Chain Tensioner Failure (C***)

Gear case (3)A first glance at a chain diagram may be confusing, since the engine has 3 distinct chain systems in 3 layers. The outer chain is just a short chain from the crankshaft down to the oil pump. The timing chain for the camshafts is in the middle. The inner chain is for the two balance shafts, one of which drives the water pump using a tiny toothed rubber belt.

VW and Audi 2.0T chain driven TSI engines from 2008 to 2013 have some issues relating to the timing chain tensioner. The affected engine codes are: CCTA, CBFA, CAEB, CAEA, CDNC and CPMA. Starts with a “C”, think C for Timing Chain. On these engines, there is an early version of a timing chain tensioner that may fail and collapse. The timing chain system may skip just one tooth, then the MIL (Check Engine Light) will come on and the engine will run poorly. The fault code will initially be OBD-II Code P0016 for Crank / Camshaft position sensor correlation. STOP DRIVING!! The next time the engine is started or driven the cam may skip another tooth, and expensive damage occurs. Many times, the chain system will skip more than one tooth initially, in which case the damage will include a minimum of bent intake valves, and of course the engine will not run. In most cases, a code for P0328 Knock Sensor 1 Circuit High Input will be set as the quartz knock sensors pick up the loud clatter of pistons hitting valves. In many reported cases, the chain has skipped a lot of teeth at once, bending all the valves, and possibly ruining a camshaft and/or cylinder head.

The early tensioner has a row of fine teeth across the top of the tensioner center shaft. A three-tooth puck is held against the shaft by a spring steel band. All timing chain tensioners in all motors have oil pressure pushing against the back end of the shaft. As the chain and guides wear, the puck should jump out to the next set of teeth, keeping the tensioner from collapsing when oil pressure is low, or the engine is stopped. One issue is that the puck is not as hard as it could be, and the 3 teeth can get progressively damaged until they lose grip. Another problem can be that the spring steel band jumps off the top of the puck. In practice, all cam chains want to vibrate due to the pulses that occur as individual cam lobes open and close. When a lot of vibration occurs just as the puck is about to move to the next set of teeth on the tensioner shaft, the teeth on the puck can get chipped, especially if the puck rocks in rotation around the shaft. Crappy 10,000-mile-old oil will contribute to the process. The tensioner only has to go slack once to skip a tooth or more.

The replacement update tensioner has teeth and grooves that go all the way around the center shaft. There is a spring steel ring that engages each groove between the teeth completely. If a client has been faithful with 5000 mile oil changes, then it is likely that the chains and guides may be in good enough shape to just replace the tensioner. The other two chain systems for the oil pump and balance shafts / water pump do not have any history of early failure or malfunction.

Some sources say that the motors with the early tensioner that fails go through 2013 on certain models. Other sources declare that all engines built after 07/2012 should have the latest tensioner. Prudent sources concur that no one is 100% sure. There is a VIN Check webpage from the Class Action Suit website described later in this article, but it may go inactive after the class action suit is over.

Fortunately, the manufacturer placed a rubber inspection plug on the lower timing chain case cover right over the tensioner. The original intent of the rubber plug was to be able to check the timing chain system for stretch and wear. The limit for exposed teeth on the original style tensioner is 7 teeth maximum. If more teeth can be seen through the inspection hole, then the chain system is worn out and must be replaced. Removing the plug to confirm chain condition and the type of tensioner takes around a half hour. The inspection should be done with the engine warm so the rubber plug is more pliable. The plug may break if the engine is cold, but said plug is available as a separate replacement part. The timing chain case cover is made from light sheet metal and will be warped / damaged during removal. It must be replaced any time it is removed, or oil leakage is pretty much inevitable. The cover contains the crankshaft seal, and its exact position is critical. The dealer will not replace this timing chain case cover during a tensioner / chain job because warranty will not cover it.

In the case of the code P0016 for Crank / Camshaft position sensor correlation, the valve cover must be removed and the cam positions checked with the factory tools used for changing the timing chain. One tooth off may well indicate that all the valves are OK, and the engine just needs the tensioner and maybe the chain and guides replaced. DO NOT CRANK the engine for a compression test! DO NOT DRIVE the car! If the camshafts are in the correct positions, then the code may have been set due to a problem inside the cam bridge. One can perform a leakdown test to confirm valve condition, but ONLY turn the engine by hand. By the way, don’t expect excellent leakdown figures like an earlier engine, the factory cuts these exhaust valve seats too thin. Valve guide and seat wear is the norm.

Failed Screen Inside the Cam Bridge

The cam bridge is the aluminum housing between the two camshafts that controls the oil pressure and flow to the cam gears, which control the rotational adjustment of the angle of the camshaft versus the crankshaft. Inside the cam bridge is an oil gallery with a screen on top of a non-return valve, which is a check ball. A common failure mode is that the screen breaks loose and either props the check ball open, clogs up the oil flow to the camshaft gear, or actually gets inside the gear. In all cases, the cam timing is affected, and the same cam allocation code can occur (P0016 for Crank / Camshaft position sensor correlation). Additionally, there is some chance that bits of the damaged screen can prop the non-return valve open, which can potentially cause low oil pressure when the engine rpms drop as it returns to an idle and a corresponding low oil pressure warning light. A Technical Service Bulletin was issued that describes the basics of this screen problem and its repair. Simply, the bridge and possibly the cam gear must be disassembled, and the screen and any debris must be removed. The screen is not necessary, and is not to be replaced. The dealer most likely will not disassemble the cam bridge to remove the screen during a tensioner / chain job.

Repairing the Damage

There are many sources for the replacement tensioners, most of which are sold as kits with the tensioner, chain, and guides. Some sell a complete kit with all three chains, and every tensioner and guide. All the timing chains on this engine are gear type chains, also called toothed chains, as opposed to the older roller chain design, which is like a bicycle chain. Each link consists of layers of flat steel plates instead of a pair of rollers with flat side plates between them. The design is lighter, stronger and more physically efficient for energy transfer. In many cases, tensioner updates done before the engine gets any damage do not require that the chains get replaced. The condition of the chains and guides will of course depend on the customer’s maintenance habits.

In the case that the tensioner failure caused major engine damage and bent valves, the chain, guides and tensioner must be replaced. First the cylinder head should be removed to check for piston damage and the possibility of bent rods. The cylinder head must be accurately assessed since some failures that bend valves may damage the camshaft and/or the cylinder head, and complete head replacement is required. Obviously, the worst case is that the pistons have large dents and maybe some rod got bent, and the entire engine must be replaced.

Class Action Suit

Volkswagen / Audi capitulated to a Class Action Suit for those who had to replace tensioners, and/or chains, or had to repair an engine after damage was caused by a failed tensioner. The repair must have taken place within 10 years / 100,000 miles of the vehicle delivery date. The suit was won in June of 2018, and the deadline to postmark a claim, or file a claim online, was January 25, 2019.

The website for the class action suit is still up and one can check if your car was covered by entering your VIN number online at the Class Action Suit website, or just click here for the VIN Lookup Page. Use this link for the webpage for the old Class Action Suit: TimingChainLitigation.com

We are not offering any legal advise, we fix cars, not lawyers. It should be mentioned that the future can only hold more and more likely failure for each of these defective tensioners. It is only a matter of time and mileage. Frequent oil changes and driving more gently may prolong the life of the tensioner, but we don’t recommend that you do nothing. If you have one of these cars and take no action, there is some possibility that your tensioner will break and your engine gets destroyed.

Once another pile of damaged engines occurs, another class action suit may be filed. Understand that we feel that a recall might be merited, but the legal beagles know that the expense would be mountainous, Billions vs. Millions.

Feel free to call us for your VIN number and chat about your options. We are currently offering to remove the rubber plug and inspect the tensioner for $20 so you can have a better idea what may be in store for your engine. If we find the old style tensioner and there are more than 4 teeth showing on the adjuster center ram, we highly recommend that you buckle down and replace the tensioner and chain. Please take care of this, we are trying to save as many engines from long term failure as we can.

We are offering a better job than the dealers. At Karmakanix, we replace the lower timing chain case cover on every job, because we know that leaving the old one will certainly cause a leak. We also disassemble the cam bridge to remove the check valve screen as per the factory TSB, preventing the possibility of a future breakdown.

Gear case (3)