I'm in the process of doing some research on my next vintage car purchase. I'm a kid of the 80's and have always loved the 928. I've had a hard time getting reliable information about the car by just asking generic Porsche people because the community is so 911 centric. I can also find 1000 books on 911's but almost none on 928s. As a result, I wanted to probe the 928 experts for some insights.

I'd be considering a manual transmission 928. I do all the work on my cars, including engine rebuilds, etc. This purchase would be my winter car. It would replace my 1989 XJS which has strange intermittent problems when the outside temp is below about 10F.

I've heard a lot of rumors about 928's having reliability problems and being expensive to maintain. None of these rumors are ever specific about what the problems are.
- Is there any truth to the reliability rumors?
- In general, how is the 928 reliability?
- What are the common reliability problems?
- Were any of the reliability problems improved in later revisions of the car?
- How many years after the car was first introduced did it take to work out the major kinks?
- Is there a reliability difference between the 2 and 4 valve engines?
- How does the reliability compare to a similar vintage 911 or 944?
- What is the lifetime of a cam belt made from modern materials?
- Do these cars have any known problems dealing with the cold?

Assuming the car tests fine on a leakdown test and I change the cam belt, what other areas are a major concern?

 

I am far from an expert but the first thing that jumps out at me is "below about 10F". My manual '79 shifts very stiffly in cold weather (below freezing) until it gets up to operating temp. I believe this is a common problem. The manual trans did get updated as time went on, possibly newer ones don't do this. You will find many auto lovers here too.

In general the problems with the 928s are with the maintainers, not with the cars.

 

Absolutely.

Nearly every problem I read about here comes from some odd thing or another that the previous owner or his mechanic did to the car, not the car itself.

I have had mine 11 years. It was a one owner car before I got it and the guy never touched it.

So, I can say that I've driven this car 11 years without a single reliability issue of any significance.

In the entire time I've had the car, the problems have been:

1) Had a fuel pump relay go bad, had a spare in the car.
2) Drain hose for the sunroof got clogged and a little water leaked in.
3) Headlight washers quit working.
4) Put a battery charger on the underhood posts with the charger plugged in (I'm a moron) and bought a new LH brain

Like any of these "super" cars, proper and regular maintenance removes most of the reliability issues.

I live in Texas so I can't comment too much on the cold weather stuff I've only driven the car once with the outside temperature below freezing.

 

Agreed. The cars are publicly categorized as complicated. They are not. Based on what you read in the forums, these are hobby cars, very maintainable by shade-tree types like us. Modern high performance cars are scary for what they will cost to maintain as they age.

Parts are not prohibitively expensive, same argument as above.

By the time the automatic-equipped versions get to be this age, a peculiarity with thrust bearing loading has been a problem with some cars. Some cars are susceptible, some seem to be immune.

Unfulfilled periodic maintenance is a real problem with some 928s, and those examples should be avoided by all except the recyclers and extreme project oriented. Unfortunately, those examples set the perception for the entire class of vehicle in the mind of the public.

 

Welcome to the tank!


1) Reliability problems with a 928 are almost always due to deferred maintainence. If they are maintained proerly, they are utterly reliable. Problem is that it often takes $10000 to make a $5000 into a $10,000 car. Get the best example to start with. If a car has maintenance records, it helps. The 16V cars are easier to maintain, and have less of a chance of catastrophic damage if a waterpump or timing belt fails. Most 16V engines are non-interfearance design... (though you don't get the power of the 32V.... and you want that... er... I mean I want that...)

2) Timing belt, water pump, cam gears, oil pump gear, crank gear, timing belt tensioner. These items comprise the heart of the 928. I can't recomend a Porkensioner (aftermarket timing belt tensioner)highly enough.

3) You will at some point replace all of these items. Steering rack, fuel pump (inside the tank and outside the tank pumps), and motor mounts.

4) Porsche always improved the models as they aged. Later cars (GTS) have oil pan baffles and 5.4L engine. Most parts from later cars will retrofit the older cars. The 928 engine seems to have issues oiling the #2/6 con rod bearings under racing conditions (huge tires, left hand turns). Racers modify their skirts, sometimes "chevy" drill the crank and/or add accusumps to help with this problem.

5) The cam belt is probably good for around 30K IMHO. The system needs to be checked regularly for cam gear wear (which is easy to do).

6) The reliability of the 928 is probably better than a 944 or 911 if equal maintenance steps are taken.

7) These cars are great in cold weather. No known issues that I can think of. EDIT: The older manual transmissions had syncro problems when cold. The newer style Borg (1985?)transmissions corrected this problem.



Seeing that you do your own maintainance/engine building, you will fit right in with one of these cars. Be warned however.... These cars have a way of making all other cars look less appealing. Pick one up as soon as you can!


Good Luck!

 

Reliability is an interesting concept. If you think of it as turn the key in the ignition and head off down the road, my experience with a 928 is every bit as good as any other car I've owned.

Does reliability mean that every system and function in the car works over an extended period of time? By that standard, I would say no, even well-cared for 928s are likely to have things that stop (and start) working. For example, the up and down function of my driver's seat lumbar no longer works. It would nice if it still worked after 15 years, but it doesn't. Of course, I've never had a car with a power lumbar support, so I can't say if a 928's lumbar is any more or less likely to poop out. But it stands to reason that the more features like this a car has, the more of them can potentially quit working.

Does reliability mean the car will ignore neglected maintenance? There I think is a more complicated notion of reliability. Good example is the fuel hoses under the hood. These have a finite life and must be replaced. A number of cars have caught fire with disaterous results when these hoses develop leaks. Does that make a 928 unreliable? I suppose it depends again on how one defines reliability.

 

My .02 on this topic. I'm from MN, although living in Texas for years now. Chip, you can probably find the right car for you. I'd assume the HVAC system will need a complete overhaul in order to get heat/defrost where you need it to go. If the hvac 'hats' aren't working you'll get great heat out of your center vent. Forget the floor and probalby the defrost. parts are cheap to fix all the hats, but its quite time consuming. You'll want these systems to function properly for a MN winter car. Not to scare you away, these cars are GREAT for the DIY guy. But be prepared to spend time/money to get it right. Doesn't matter what the PO says about maintnance unless you can confirm it yourself. chances are nearly zero that all your systems will be functioning. Check all the defrost/heat functions and pay attention to where the air flow comes from. If you use the search function at the top top of the sight and look up HVAC you'll get tons of great information about how to tackle this job.
Down here in Texas we don't have much trouble, but up there I'd want every bit of heat I could get going through the defrost and floor. Especially when its 5 below. I hope you find a great car and join the gang.
Best,
Ben

 

Sounds like my Ferrari 308. I'm rebuilding most of the car because of problems of neglect caused by the previous owners. This situation sounds much more appealing to me than dealing with a car that is just poorly designed from the start.

 

I'm a hardcore DIY'r, and the 928 has, by sheer coincidence, turned out to be the perfect car for me.

Well documented. Parts available and typically not unreasonable. Designed so that almost everything can be accessed for repair or replacement. Particularly strong and well-designed motors if utilized for normal driving, with a couple of caveates, most terminal and critical being thrust bearing failure for automatics.

Its a pleasure to work on them, in a slightly masochistic kind of way.

 

How's it going Chip?

Welcome to the shark tank.

Here's an article I wrote for another website about some of the 928 myths.

What I would say about the 928 and it's reputation for requiring a lot of maintenance is this:

I think there were like fifty thousand of them built. Ever. In all the years they were manufactured combined. Compare that to well over that each year for most production cars. Most mechanics, even Porsche mechanics don't get to work on them that often so when someone comes in with one that is running rough or has some kind of maintenance problem they usually have to spend time figuring out exactly how it's supposed to work first, then find out why it's not, then fix it.

You've already found another reason: The Porsche community at large is very 911-centric so you'll find people tend to be kind of polarized toward or away from the 928 and they tend to stay that way.

Finally, I think the biggest thing has been mentioned a few times already: Deferred maintenance. The cars are dirt cheap to buy now (most of them) so you get a lot of guys who want to drive something with that Porsche crest on it or drive the car they lusted after as a kid back in the 80s (like me ) and this is the easiest one to get. Once they buy one and check on parts they find that it would cost at least as much as they paid for it to get it up to running 100%. And that's if they do the work themselves. So they fix the minimum they can get away with and let the rest age.

The cars are built to last forever but because they look so good on the outside, people don't realize that the rubber fuel lines and plastic bushings are dried and cracking. They'll drive the car for 2 years with half of the warning lights on the dash lit up or with the belt tension circuit bypassed (grounded) under the hood.

They look at the shiny freshly waxed hood and turn the key only to find that a 22 y/o power steering line has split and is spraying flammable trans fluid right on the exhaust manifold or the automatic transmission cooling line that runs across the top of the catalytic converter (on it's way to the radiator) is dripping flammable ATF onto the catalytic converter.

5 minutes of running and they smell smoke. 10 minutes later they're complaining that the car burst into flames for no reason and they didn't get any warning.

I've always maintained my own cars and the 928 (mine is an 'S3') is by far the best engineered and easiest car to work on of any of them. It's really well designed and when it's running well there's nothing like it.

Good luck and if you get one, keep us posted!

 

since you are coming from a well known "issue" car in the jag...I'd say 928 ownership will be easy for you....they have a bad reputation, but really aren't that hard to work on.....stay on top of a few key things and the cars are generally reliable.....

The important things are:

1: Timing belt-waterpump (more important on 32v engines that are interference motors)
2: Thrust bearing-torque tube checks on 85+ automatic's

those are the quick killers of 928 engines that cost $$ to fix.....stay up on those and you'll be fine...

 

One thing for sure - you are unlikely to find such a wealth of 928 knowledge and help, freely given for any other car than the 928 !!

Just enrol as a Rennlist Member, and enjoy owning a 928. They are great cars. Buy the best example you can, guided by the people here.

I've had mine 11 years, the only problems I had have been atributable to a local Porsche Official Centre, who I used in the first year of ownership before I felt confident enough to do the work myself.

 

I have had 5 928 throughout my lifetime and all of them have been fairly reliable. I think majority of these problems are electrical but thats to be expected. Replacing a 20 y/o window motor or wiper motor is to be expected in my opinion. I have had some old coolant hoses burst one time but after that was done I replaced them all and the car was reliable again. I currently drive my Cassirot daily and she is turn key. I think the big issues with these cars are torque tubes, converter bearing, and t-belt. If the t-belt hasn't been changed or you don't know when it was last changed do it. If the torque tube fails its a big job to do but very rewarding! My local shop wanted almost 5k to do this job hence the reason I did it myself. The big thing is, if you can work on these cars yourself you will be OK! These cars are not all that hard to work on in my opinion! Good Luck!

 

Thrust bearing failure can also affect the earlier automatic cars if the shop removed the circlip system.

 

Thanks for all the help. All of you are doing a great sales job since you think this is the perfect, best engineered, best looking, most reliable car ever.

I went through and made a summary of the notes so far.

- I'll need to replace all of the fuel, power steering, and AT lines in the car or risk a fire.
- I'll need to replace the timing belt and water pump. While at this, I'll need to check the cam gears, oil pump gear, crank gear, and timing belt tensioner.
- I should inspect for HVAC problems and will probably have to fix them.
- Thrust bearings are a problem for AT.
- Early manual transmissions have low temp problems. This was fixed at some point (1985?).
- Torque tubes can have problems. (Is this any more complicated than a fancy enclosed driveshaft?)
- Converter bearings can have problems. (Torque converter?)

Since I'm set on a manual transmission, how can I figure out if 1985 was in fact the year the low temp problems were fixed?

Are the torque tubes and converter bearings problems just for AT cars? If not, can someone provide a description of what exactly the problem is?

Given that the Porsche world is 911 centric, is it worth paying a Porsche specialist for a PPI on a 928? I can do a very thorough inspection of the car, including a leakdown test, but I don't have a lot of model specific knowledge.... but it sounds like the specialist doesn't either.