Reliability of 4WD on 1989 911C4

[dennish]

I'm looking to buy my first 911. It's a 1989 C4. I'm wondering about the potential problems with all the added mechanics and technology of the 4WD. Am I looking at big problems down the road? After reading the new car reviews of the this car, I can't help being impressed. But now with nearly 100k on the mechanism what can I expect as far reliability. Thanks for any input before I spend a hunk of my life's savings.

[GothingNC]

I would ask the members on Rennlist.

They have an active 964 forum.

[racer]

I'd emagine like most things porsche, they are incredibly reliable until they break, then they become incredibly expensive to repair

Both Mileage and Age (21 years, 100K miles) will have taken some toll. If you can, get a PPI from someone who knows the 964/C4.

[sandro.m]

Don't want to ruin your current impression of the car. But if I were you I would never ever buy a C4 again. No comparison to a RWD Porsche.

As you might know, it was PAG's first attempt to build a car with AWD. In my opinion they completely failed at that time. The 964 C4 does not reflect a Porsche feeling on curvy roads. It has a known understeering issue which is in most cases not even with PSS9 or KW3 coilovers avoidable.

Do yourself a favor and get a C2.

Just my 0.02 cents.

[spuggy]

I've read that the 964 C4 used much of the FWD technology developed for the 959 - and it's heavy, over-complicated and very expensive to fix.

The later AWD cars are much simpler - and good used parts are much more plentiful.

[cellison]

Originally Posted by spuggy

I've read that the 964 C4 used much of the FWD technology developed for the 959 - and it's heavy, over-complicated and very expensive to fix.

The later AWD cars are much simpler - and good used parts are much more plentiful.

+1. i would stay away unless it is almost willed to you.

[GregB7S4]

I bought a high mileage (165k) 964 C4 a couple of years ago, and sold it fairly soon after. During my brief ownership I did not experience any problems with the AWD system, nor was there any evidence of AWD problems in the service records. I just wasn't a fan of the way it drove, steering was not Porsche-like and it felt ponderous compared to my previous C2. The 964 AWD system has alot of sensors and components that are very costly to replace, and although they do not seem to fail often, when/if they do they are not cheap. That coupled with the fact that I didn't like the car as much as the C2 led me to sell it. I much preferred the feel and simplicity of the 993 C4's AWD system.

[carjmark]

+1 on the heavy understeer characteristics of 964 AWD. Although you asked about the AWD, the biggest concern I have with these cars is the problems many of them have with head to cylinder sealing.

Cars built from 89' through mid 91' had a had seal structure that didn't use gaskets, many of these seals leaked and were either repaired by Porsche, Previous owners updated or they are still stock. This is very expensive to update to later solution involving removal and machining (plus all the while we're in lets do... costs).

Estimates very from "all" of these cars eventually leak to "many" do but you can be in for a very large shock and bill. I would not consider an early 964 without proof this work has been done or allow a major discount even if it's dry. Another mid $4 figure+ reason for a good PPI.

[GregB7S4]

Originally Posted by carjmark

+1 on the heavy understeer characteristics of 964 AWD. Although you asked about the AWD, the biggest concern I have with these cars is the problems many of them have with head to cylinder sealing.

Cars built from 89' through mid 91' had a had seal structure that didn't use gaskets, many of these seals leaked and were either repaired by Porsche, Previous owners updated or they are still stock. This is very expensive to update to later solution involving removal and machining (plus all the while we're in lets do... costs).

Estimates very from "all" of these cars eventually leak to "many" do but you can be in for a very large shock and bill. I would not consider an early 964 without proof this work has been done or allow a major discount even if it's dry. Another mid $4 figure+ reason for a good PPI.

Mostly agree, but I would not automatically avoid (or discount) an early car that does not leak. Get a good PPI and make a decision based on the overall car. Not all of these early engines leaked and chances are if it hasn't leaked in 20 years it probably won't leak IMO. Many of the later cars (including 993s)leak too, just from different places.

[gregwils]

Excellence mag provides assessments and values for all past Porsche models. I think Bruce Anderson writes the series. He said he had a friend that referred to the 964 C4's awd as Sputnik II. I have also seen posts where people have listed cars with 150-200k miles with a 964 C4, so like racer said probably reliable, but really expensive to fix. I too would get a 993 if I really wanted awd.

[Matt Monson]

My business is Porsche gearboxes, and only Porsche gearboxes. My professional opinion of the 964 C4 is that the 4 wheel drive system in the car is both complex and reliable. Because it did spring from 959 product development and components, it was a decade ahead of everyone else's system when it came out. However, these days, many of the components that could fail are hard to come by and very very expensive to acquire. One could easily spend a couple thousand dollars on electronic bits that are no longer used or present on the 993 and newer 4WD systems.

In fact, they are so expensive, it's not uncommon for people to convert the cars to 2wd or update to a 993 4WD system instead of repairing a broken 964 4WD system.

Personally, I wouldn't steer away from them because they can be had for substantially less for their 964 C2 counterparts or any 993 model. Here in Colorado, with a good set of snows you could drive on year round, and as long as you aren't looking for a track toy, it's a more than capable daily driver for canyon runs and around town driving. But on the track, 4WD is a hinderance and not what I would look for in a car that I want to lap quickly.

[Doug&Julie]

...Thanks for any input before I spend a hunk of my life's savings.

Don't. Just don't. I "experienced" a high mileage 964 over the summer. I drove it from shop to shop fixing this and that, and after three months couldn't get rid of it fast enough. I'm too ambarassed to say how much I wasted on it. If you're worried about you life savings, look at another model.

[KNS]

People are converting them from 4WD to 2WD? What does something like that cost? It seems there are so few 2WD (manual trans) cars out there, the thought of ripping out the 4WD components and making it a C2 is interesting...

[deathpunk dan]

This is so disheartening to read as I have always wanted a 964 C4.

[techweenie]

The other issue with the first couple years of 3.6 engines is that Porsche tried sealing the heads to the cylinders without gaskets. This didn't work, and required disassembly and machining to fix. By now. most engines will have been done, but you'd want evidence of that, because it's pricey.

[Doug&Julie]

Originally Posted by deathpunk dan

This is so disheartening to read as I have always wanted a 964 C4.

I did too, which is part of the reason I bought mine. It was an "opportunity" at a time when I though I could "afford" it. Dynamically I loved it. Smooth power and great handling (understeer aside) and awesome brakes. I can see why the 964 is such a popular model. But make no mistake...they take money to run and keep running. I had heard this before, but truly shocked at the extent of this. So I feel some obligation to pass on my experience.

[powerboatnut]

Originally Posted by Doug&Julie

I did too, which is part of the reason I bought mine. It was an "opportunity" at a time when I though I could "afford" it. Dynamically I loved it. Smooth power and great handling (understeer aside) and awesome brakes. I can see why the 964 is such a popular model. But make no mistake...they take money to run and keep running. I had heard this before, but truly shocked at the extent of this. So I feel some obligation to pass on my experience.

Doug&Julie,

Please be specific about your 964 and what failed (and when) with costs....I am looking at what appears to be a very clean 1990 C4 and am trying to gather as much info as possible in order to see if I want to go to expense of paying for a PPI and compression/leakdown testing on it.

Here is my thread to see some of the details of the car:

http://forums.pelicanparts.com/porsche-911-technical-forum/581413-looking-first-911-need-help-possible-car-found.html

Anyone else out there that has some history or repairs and reliability please post as well.

Thanks

[914efi]

I looked at the recent values in Excellence and noticed the 964 C4s are a bit higher than C2s. I would have thought with all of the horror stories that they would be much lower. I have never owned one, but I think they are cool.

There was a great thread about the C4 RS (CS?) where stripping out the AWD electronics and other weight was discussed, that would be a fun car.

[GregB7S4]

Originally Posted by 914efi

I looked at the recent values in Excellence and noticed the 964 C4s are a bit higher than C2s. I would have thought with all of the horror stories that they would be much lower.

The values listed in Excellence are widely regarded as inaccurate. They also list targa values as higher than coupes. You can spend hours poring over them and come up with inaccuracy after inaccuracy. Bruce Anderson needs to pass the baton to someone with a current understanding of the used Porsche market.

[Matt Monson]

Originally Posted by KNS

People are converting them from 4WD to 2WD? What does something like that cost? It seems there are so few 2WD (manual trans) cars out there, the thought of ripping out the 4WD components and making it a C2 is interesting...

The primary cost is a good used G50 5spd gearbox. With the recent popularity of the G50 in kit cars the price of a good used box has gone way up in the last few years. Expect to spend $3000-4000 for a good used box or $2000 for a core and another $3000 to rebuild it.

It's been a while since I've been involved in the conversion of one, but there's other bits and pieces that are required. The only real downside is that the C4 chassis weighs more because of the extra sheetmetal in the tunnel for the AWD. But if you aren't looking to build a racecar, it's not really an issue.

As Greg mentioned, I don't buy Excellence's assessment of a C4 being a more expensive car to buy. My experience has generally been that they trade hands for 10-20% less than their contemporary C2 counterparts.