Lately, we’ve noticed a growing number of valve failures being reported for certain VW and Audi vehicles, in particular those with the 1.9L diesel TDI and 1.8T gasoline engines.
After reviewing many cases of these failures, it turned out that the problem was not with the valves themselves, but with the method of cylinder head overhaul. Most failures occurred shortly after a rebuild, and appeared to be mainly attributed to the poor adjustment of the hydraulic lifters.
- Hydraulic lifters must be adjusted at the same time as any new valves are adjusted
- All parts should be installed in conditions of pristine cleanliness
- Each follower must be coated with an extreme pressure cam lubricant as used on the lobes
- Old engine oil must be drained and replaced with both new oil and filter, as old dirty oil will contaminate the new lifters, leading to early failure
- Hydraulic followers must be allowed to “settle” for a MINIMUM of 30 minutes, after the installation to allow the excessive oil in the hydraulic lifter to drain. If this step is not completed, some valves may make contact with the piston crown leading to an immediate fracture in the cotter groove on start up
- Engine must also be allowed to “settle” for a MINIMUM of 30 minutes when the repair is ready, then cranked over carefully for TWO complete cycles by hand to check for valve to piston contact. Ideally, it is recommended that the engine to be left overnight before restarting for the first time after the repair.
This post applies to the following VW Audi valves: 058109601C, 058109611E, 058109611M. However, these important best practices should apply to all work in the valve train area, and should be taken into consideration for ALL engines that use hydraulic lifters.