Mine is an '85. Technically it's considered an S3, even though they only call it an "S" model. Mine is the third revision of the 928S model. S4 is the fourth revision and it came out in '87.
Maintenance costs are very high. The 928 community are always working on ways to lower, eliminate, or simplify those costs. As an example, '83-95 928s all used the same motor mounts. They were hydraulic mounts filled with a viscous fluid to help dampen noise and vibration. The problem is the price of the mounts. They cost about $350 apiece and you need 2. Porsche will sell their engineering services to the highest bidder even if the bidder is another car maker. Back in the 80s, they did some work for Volvo and Ford. So the first solution that the 928 community discovered pertaining to the motor mounts were motor mounts from the Ford Ranger. They were quite similar to the 928 mounts because Porsche designed them for Ford. Eventually, after more catalog searching someone discovered that motor mounts from the late 80s Volvo 740 Turbo were an almost exact, drop in replacement. The Volvo mounts cost $40 apiece. The 740 Turbo actually shares several other components with the 32 valve 928s that help to reduce costs and increase availability of those parts. By using mass produced, off the shelf parts from other vehicles, starting in '85, the quality/reliability of the 928 skyrocketed.
The one part that is most worrisome for many people is the timing belt and water pump. If you cut the timing belt and lay it out, it's about 7ft long. Porsche fucked up when they designed the engine and didn't use an auto tensioner for the timing belt. It used a mechanism that required manual adjustment from time to time. Basically, you'd have the timing belt installed, and then you'd have to bring it back 1000 miles later to have it adjusted, and from that point, you had to bring it in every 15K for inspection and adjustment if necessary. This was a fucking nuisance. A fellow owner out near Seattle or Portland designed and produced a bracket that would allow the car to use automatic tensioner parts from the VW VR6 engine. Parts that are readily available and this eliminates the need for periodic inspection and adjustment.
The price to maintain them means that many are poorly maintained. It also keeps the values of the cars lower than they should be. You can't be fooled by a cheap 928. We've got a saying when it comes to them. You can buy a 928 for $2K. But then you'll wind up buying $10K in parts to repair all the problems and catch up all the deferred maintenance, at which point you'll have a nice car that's worth $5K. The other saying: Never add up your receipts.
In a nutshell, once you get them sorted out, they're incredible to drive and quite reliable.
Maintenance costs are very high. The 928 community are always working on ways to lower, eliminate, or simplify those costs. As an example, '83-95 928s all used the same motor mounts. They were hydraulic mounts filled with a viscous fluid to help dampen noise and vibration. The problem is the price of the mounts. They cost about $350 apiece and you need 2. Porsche will sell their engineering services to the highest bidder even if the bidder is another car maker. Back in the 80s, they did some work for Volvo and Ford. So the first solution that the 928 community discovered pertaining to the motor mounts were motor mounts from the Ford Ranger. They were quite similar to the 928 mounts because Porsche designed them for Ford. Eventually, after more catalog searching someone discovered that motor mounts from the late 80s Volvo 740 Turbo were an almost exact, drop in replacement. The Volvo mounts cost $40 apiece. The 740 Turbo actually shares several other components with the 32 valve 928s that help to reduce costs and increase availability of those parts. By using mass produced, off the shelf parts from other vehicles, starting in '85, the quality/reliability of the 928 skyrocketed.
The one part that is most worrisome for many people is the timing belt and water pump. If you cut the timing belt and lay it out, it's about 7ft long. Porsche fucked up when they designed the engine and didn't use an auto tensioner for the timing belt. It used a mechanism that required manual adjustment from time to time. Basically, you'd have the timing belt installed, and then you'd have to bring it back 1000 miles later to have it adjusted, and from that point, you had to bring it in every 15K for inspection and adjustment if necessary. This was a fucking nuisance. A fellow owner out near Seattle or Portland designed and produced a bracket that would allow the car to use automatic tensioner parts from the VW VR6 engine. Parts that are readily available and this eliminates the need for periodic inspection and adjustment.
The price to maintain them means that many are poorly maintained. It also keeps the values of the cars lower than they should be. You can't be fooled by a cheap 928. We've got a saying when it comes to them. You can buy a 928 for $2K. But then you'll wind up buying $10K in parts to repair all the problems and catch up all the deferred maintenance, at which point you'll have a nice car that's worth $5K. The other saying: Never add up your receipts.
In a nutshell, once you get them sorted out, they're incredible to drive and quite reliable.