Q – I have a 1986 Porsche 944 that I just purchased last year. It is my first Porsche and I absolutely love the car. When I was considering the car, I had a local shop check things over. One of the several things they recommended was replacement of the timing and balance shaft belts. The belts on the car didn’t “look bad,” and I had paperwork showing that they had been replaced in 1995, about sixteen years before…but they only had about 20,000 miles on them. The water pump and all of the pulleys that the belts ride on were replaced at that time. The shop that made this recommendation said that it was an age-related suggestion, that timing belts should be replaced preemptively every ten years or so, regardless of the mileage on them. I’d heard that advice from other Porsche owners, so I told them to go ahead and do it. They told me at the time that the pulleys “sounded good” and didn’t have any noticeable problems…unlike the belts, they said, the pulleys don’t have an age-related failure record, so they didn’t replace them at that time. I was somewhat relieved, since they had mentioned that the pulleys plus labor would cost a few hundred dollars extra.
Fast-forward about six months: I’ve got the car in that same shop for an oil pressure warning issue. My oil light came on a few times, and I had it taken to the shop immediately. While they were working on checking out the oil pressure, they noticed a whining noise coming from under the timing covers. They removed the covers, and heard one of the tensioner pulleys for the timing belt making both a whining and a clicking noise. Now they’re telling me that they want to replace the pulleys…and that it’s going to cost as much as the timing belt job they did six months ago! What gives? Why didn’t anybody tell me to replace the pulleys when they first had it apart? – Mike
A – Mike, this is a sensitive topic. The question of whether to “shotgun” a timing belt job gets more complicated when the job was done a long time before. It is certainly true that rubber will dry-rot with age, and that it is a general, industry-wide bit of conventional wisdom to replace timing (and balance shaft) belts at roughly ten-year intervals. It is also true that the idler and tensioner pulleys can live a much longer useful lifespan than the belts; being mostly metal, they wear out much more due to mileage than failing due to age. At our shop, we have performed belt replacements with and without pulleys, and frequently, the pulleys can last twice the lifespan of the belts. This can be very convenient for the car owner, as it does reduce the cost of any given replacement operation.
It is also true, however, that if the belts are replaced without replacing the pulleys (or water pump) and one of those components fails at a later date, the whole thing does have to come back apart. Because of this fact, and because just getting the belts off and on takes anywhere from five to seven hours, we usually recommend a “shotgun” replacement of the pulleys and the water pump at the same time as the belts. I wouldn’t necessarily blame the guys who just did your job…if the pulleys were not making noise at that time, and if there was evidence that they were only 20,000 miles old, the shop had every reason to believe that they could save you a fair amount of money with no penalty. It’s a tough call.
To add yet another element of complexity, there are multiple oil seals on the front end of the motor (camshaft, crankshaft, and both balance shafts) that can also only be accessed during a timing belt removal and reinstallation. At the very least, those seals need to be inspected closely…if there is ANY evidence of leaks or seepage, it’s time to replace them! If they are “bone dry,” then it becomes an optional thing, just like the pulleys. Replacing all of the seals at once tacks on yet another several-hundred-dollar charge, and so again it’s a tough call. We usually don’t insist on seals, but we do inspect them closely, and any hint of wetness triggers the “red light” for our techs. MC