Needed new front brake discs at 300000km.
Right rear wheel bearing needed adjustment at about 330000 km, after overheating due to forgotten handbrake.
Injection system was freshly rebuilt when I bought the car, after cable fire/short circuit near the cold start valve.
The front brake lines failed MOT in 2004 due to rust, was cheaply and easily replaced.
The right hand rear wheel brake cylinder seized in 2003, was replaced by cheap after-market part.
Heater fan seized in fall 2004, after coolant leak in heater core. Replaced by used part from the scrap yard (about 15 Euro) The core was replaced by new one, at 70 Euro, parts only. Replacement was tricky, but with a "Haynes Manual" nothing is impossible.
Engine oil light is flickering at hot idle, probably worn pump and bearings inside.
Compression has most likely gone down, and "blow-by" occurs into crankcase, diluting the oil with petrol.
Final drive gears make whining noise between 80 and 120 Kph.
Gearbox oil leaks around the driveshafts.
Front shocks and springs slowly worn out; replaced in June 2005.
Both outer tie rod ends replaced in June 2005.
Brake distribution valve rusted stuck, need replacement.
Engine rubber mounts failed during "inspired" driving session in 2003.
Fuel meter sticks at random positions, sometimes comes loose in bumps and works for a while.
Rear springs are weak and will soon need replacement.
Drivers seat height adjustment is unreliable and sometimes the seat falls back down.
Outer doorhandles are often broken, and it is getting hard to get hold of new ones. They freeze stuck in the winter, and snap if you try to force them.
Engine boiled once, due to failed thermo-contact in the bottom of the radiator (Which means the electric fan wouldn't start). Luckily the head gasket survived. Used contact bought at scrap yard.
The Valve tappets are noisy for a short while after a cold start, but that is almost a standard feature.
Timing belt replaced, for good measure, at 350000km.
Windshield washer pump died yesterday.
Driver's side heated seat does not work.
Exhaust pipe cracked just under the flange at the manifold. 3 times welded and cracked a few cm lower after about a year. It seems impossible to get hold of a new pipe from manifold to catalyzer; almost all 100's has the double pipe, but 1988A 1.8 has a single pipe that is apparently out of production.
Starter motor is sometimes misengaging with loud noises. Will need to be fixed.
This car is economical. It is the cheapest version that was available of the 100, that is, four cylinder 1.8 injection engine (carburettors were not available in -88 in Sweden due to new legislation about catalytic emission control). I has manual windows, a manual sunroof, manual mirrors, no power steering and no air condition. I guess you could call it a grown up VW Jetta :-)
It will do 90-130 Kph for hours on end using only about 7.5 liters of petrol per 100km, regardless of load. It takes about 9l/100km to and from work which is barely far enough to warm up the engine.
The engine is the same block that was used in Golf, Passat, Jetta, Audi 80 and others in the '80s, and it has a reputation for being very long-lasting. It doesn't use much oil for its age, I add a liter every 1500-2000 km, and change oil & filter every 20000km..or so.
Spare parts are available from cheap after-market sources, and also common in scrapyards, so repairs are cheap provided you can do the work yourself... which you can, in the simple versions of the Audi 100, as opposed to the luxury computerized, turboquattro monsters.
Comfort is good, but compared to newer cars, and to the more expensive models of the 100 at the tine, the 1.8 is noisy, needing higher RPM's to gain speed. The worn rear suspension makes it a bit bouncy over speed bumps (it bumps twice). Heating is excellent after the core replacement, minus 25 centigrade is no problem.
The car is roomy, and seats four full grown adults comfortably for hours and hours. five can travel reasonably well, provided atleast one is a little thinner than average and two are not heavyweights :-)
The boot is big, wide, long and deep, for a sedan, and is almost never a problem.
The steering improved a lot with new front shocks and tie-rod ends, of course, but it still is a very front-heavy car, with huge overhangs both front and rear. It is very steady in high speed, but rather unwilling to corner quickly. The steering is heavy and gives you strong arms and firm gripping hands, when parallel parking and such, but at speed you can drive with thumb-and-index finger grip and it doesn't wear you out.
The gearbox is nice, with short, reasonably precise shift movement.
The brakes are under-dimensioned for this heavy car, and are bigger on the five cylinder models. Three or four hard stops from 100kph in rapid succession will make them fade badly. For everyday driving they are adequate, but need a little harder pedal pressure than most other cars of the same age.
There is designed-in impact zones in the body of the car, but the cheap models don't have seat belt tensioners or airbags like the more luxury ones. This combined with the sort of weakish brakes makes no more than an average grade.
The car is reliable, in the sense that it has never once failed to bring me home, not even after boiling - I let it cool, and hardwired the fan to run all the time, for the trip home and then got a new thermo-contact. I did not hesitate to go to norway last winter, 1600 km one way, in snow and ice - I feel that is a good reliability testimony for a 17 year old car.
Great car for getting from A to B for very little money, and with very little effort. Not very fast, not very luxurious, but it gets you there - and back.