Pboden

Have a -87 S4 that just has reached 280 000km (174 000 miles), so it has a pretty long milages history. The engine still looks, smells and sounds good, but other than this is not a good selling point on the market (when selling) what could I expect of worries and failures in the times to come ?
As must of us patriots, I have done continuously service when something needed attentions. The timing belt and water pump have of course been changed.
What it the longest mileage one could expect on these 32V engines ?

WallyP

There have been reports of a few 928's with over 500,000 miles and still running well.

FredR

There are plenty of examples of engines running well way past your mileage but as you note the attention to maintenance makes all the difference. If oil pressure is good and where it should be, then the motor should easily sail past 300k miles without major intervention.

There are other things that it might be prudent to check and replace pre-emptively, for instance the cam tensioner pads and cam chains. The cam sprockets may also be past their best by now and if you have done the cambelt and water pump then you should be aware of their condition.

As to when you should pull and strip the engine for general inspection and refresh is probably better answered by those more knowledgable on this list but I would not mind betting that for a well maintained example they will tell you the motor can run to 500k miles before thing slike mains, big ends and rings should be changed out.

That being said most people purchasing a car think they are done for at 100k miles or in my part of the world at 100k km would you believe and that usually means there are some real bargains to be had with quality car because of this [and the numbers available]. Trying to convince anyone that a motor with 200k miles plus is sound is a difficult one no matter where you are.

Rgds

Fred

Strosek Ultra

If you take good care of the car, do perform all the needed services and repairs on regular basis, do not drive too hard (I am familiar with the Norwegian speed limits and the extremely high fines) and as we are talking of an enthusiast car you probably will drive only when the weather is nice and less than 10.000 km annually, I believe you can keep the car for another fifty years.
Åke

S4ordie

Besides maintaining the engine and car well I would have an oil analysis performed each time I replaced the oil. This can be very helpful to know what metals, if any, are in the oil and therefore an indicator of the health of the internal engine components.

A well maintained 928 engine will have a very, very long life. Porsche over engineered most of the engine. It is things like old fuel and power steering lines that fail and cause fires that are a far greater concern on these cars.

hacker-pschorr

+1

It's something to appreciate if you ever browse through other forums and see the kinds of issues manufactures are having experimenting with different coatings and materials. Porsche, Mercedes, and Mahle hit it out of the park with Alusil (what our engines are made from) and never should have abandoned it.

Wisconsin Joe

FIFY

GregBBRD

The first thing you need to think about, when asking this question is what constitutes "worn out". These engines will "limp" along for many miles with imcreased oil consumption and decreased performance. If "worn out" means "will not function any longer", mileage can be very high.

What wears out, is the real question.

The early smaller bore, low output, 4.5 engines seem to be able to go more miles than the later larger bore, higher output 32 valve engines. And the longer stroke GTS engines, with the increased rod angle, show wear the fastest of all.

In my experience, a GTS engine has very high piston to cylinder clearance by 250,000 miles and the iron plating on the pistons is very poor. S3 and S4 engines go farther....300,000 miles before the pistons are a big issue.

In the 32 valve engines, by 200,000 miles, the exhaust valve guides are getting very loose and oil consumption past the guides will become an issue.

What seems to be more if an issue than mileage is time.....I'm seeing more and more deteriorated head gasket problems.....with the associated higher wear in the rear cylinders from the greatly increased heat, due to poor water flow. Additionally, the deterioration of the head deck surface, from acidic erosion, becomes a huge issue.

30 years , from a paper based head gasket, is a long time.....

996Fever

Yeah, Alusil was good stuff. Decades ago I had a BMW 750il. It's V-12 engine block was also made of Alusil. Those engines are known to hit 500k easily too if taken care of. It was the Nikasil blocks in the V-8's that were bad. Cheap gas with too much sulfur reacted with the nickel and created pits in the cylinder lining, ruining compression.

FredR

Greg,

A very informative post from the oracle!

I put the corrosion in the head deck down to inadequate coolant condition- the glycol is not the issue it is the anti corrosion chemical package that gets exhausted so slipping in a bottle of water wetter every couope of years and replacing the coolant in totality every 4 or 5 years [2 years if really keen] might be a good measure. My original GTS heads suffered from deck corrosion and had no real mileage at all on them and I put that down to lack of use by the PO- probably just sat there stagnating from time to time with no movement of the coolant for weeks on end so my theory is that that at the high point the anti corrosion chemicals get depleted locally through lack of use and off it goes. Regularly used examples with resulting higher mileage probably faring much better. As we see some folks put their 928's away for the winter months that may introduce the need for occasional circulation every few weeks [for instance?] or maybe complete coolant drainage?.

With my current S4 motor when it was removed from the wreck of my late 90 S4 the motor was 15 years old at the time and we pulled the heads as we knew there was a compression problem on No7 due to what turned out to be bent inlet valves [damaged cam cover/cam wheel caused a problem during run down after the hit], we checked all the valves, cam gear etc etc. Your comment about the head gaskets makes great sense and folks should pay attention to that gem. I would suggest it is wise to pre-emptively pull the heads on these motors every 15 to 20 years irrespective of mileage. If the original gaskets are still in place comon sense suggests they could fail any time and worse may be happening. No one likes to pull an engine but at some point a through inspection is doubtless justifed to help achieve the long term potential.

Given we had the engine out it was a good time to partially disassemble the motor. Check the oil pump for wear, look for signs of any distress in the bores etc. We did not see such so left the bottom end but with hindsight it might have been a good idea to pull at least 1 piston and check for the condition of the coating, ring gaps etc etc. At the time I felt it better to leave well alone down there and to date have not regeretted that decision given I feared that disturbing the plot might cause more problems than leaving well alone as it were. At the time the motor had only done some 70k miles or so thus we did not anticipate any wear issues. It gave consistent compression pressure readings around 185 to 188 psig, not as high as some examples but respectable I suspect [hope?].

At the moment I have it mind to pull the motor in 5 years time when it is 30 years old and the current head gaskets are 15 years old and do some more inspection and remedial works/upgrade as warranted. Whether I will feel that enthusiastic in 5 years time remains to be seen given the grey hairs and decrepit decay taking place!

Your wisdom very much noted/appreciated

Rgds

Fred

safulop

I'm looking at buying a recent BMW 650i or Jaguar XK-R, and while I eagerly bought my S4 with 133K miles on the clock and have not had any internal engine problems in almost 6 years, I am honestly scared to buy one of these younger V-8s with more than about 50K miles on it. I am insisting on a low-miler, just because I don't know how they measure up. Although I did hear a rumor about a Jaguar XK-R with 290K miles on it...