Experiences with Audi 100 2.5 TDI

Hi,

I've been thinking about getting a (used) [item].
Adding an Audi 100 2.5 TDI.
This is the 'C4' model with the 115 horsepower engine (engine code: 'AAT').
This is the model that was originally produced from 1991 to 1997 and was later renamed from 'gbeaute' to 'A6'.

Has anyone here had experience with a similar vehicle?
I would be very interested in information and reviews.

I already have a specific vehicle in mind, but it's not easy to find one with low mileage, air conditioning, and that also comes from a Volkswagen/Audi dealership.
It has 105,000 kilometers (approximately 65,000 miles) on it, and was manufactured in November 1993. Condition: 'like new!'

I test drove it.
The sound (of the inline-5 cylinder engine) is brilliant!
But is it normal that it doesn't really start accelerating until 2000 RPM?
My 1.9 TDI engine in my Golf starts producing noticeable power from just 1500 RPM.
Is it because of the 5-cylinder engine?

Thank you for your information!

Hi!

The speeds of 2000 or 2250 RPM are normal because it's not yet a VTG turbocharger!
If you want to know my opinion: I've never had any problems with the engine, but with everything else, you sometimes just have to bite the bullet.
First of all, let's talk about the brakes: it's quite embarrassing that even the 115 hp version doesn't have ventilated brake discs.
Secondly, it's a real tire killer! I could do whatever I wanted, even though the tire pressure, handling, suspension, alignment, etc., were all fine, but after 35,000 to 45,000 kilometers (approximately 22,000 to 28,000 miles), the tires were completely worn out!
Okay, I'll keep it short: The constructive design is completely outdated, and just the rigid rear axle alone is really great! (This is sarcastic.)
On the other hand, the 115 horsepower is completely overwhelmed by the weight of the car, so it's quite amusing to watch other cars with only 90 horsepower overtake you.
But decide for yourself...


Best regards: Marko

Hi there,
"Although I don't have the C4 with the AAT engine, but rather the AEL, I am very satisfied with it. Like you, my car doesn't really start pulling until around 1900-2000 RPM, but it seems to be a standard turbo (not a VTG turbo). However, there was someone in this forum who discovered a VTG turbocharger on their AEL engine."
"This car is absolutely relaxing for long journeys, but you definitely notice its considerable weight (1685 kg according to the registration document) when driving in the city."
Average fuel consumption over the last 40,000 kilometers is 6.5 liters per 100 kilometers, but this includes many long-distance trips.
It's definitely worth recommending: the 6-speed gearbox; with it, you have approximately 2500 engine revolutions per minute at 140 km/h, and the engine noise is hardly audible. (However, this may also be due to the exterior mirrors :), which whistle quite loudly in the wind.)
I haven't yet observed excessive tire wear on the vehicle; the front tires last approximately 50-60 thousand kilometers, while the rear ones last correspondingly longer. Currently, they have about 80 thousand kilometers on them and still have more than 5mm of tread left. However, this is certainly also a matter of driving style and tire brand.
The machine seems quite durable; the car currently has approximately 220,000 kilometers on the odometer. The oil consumption is close to zero, despite long distances with a relatively high proportion of high speeds (according to the dipstick, it's only about 0.5 to 0.7 liters every 15,000 kilometers between oil changes).
Meanwhile, the fuel injectors seem to need replacing, as there's sometimes a rather unusual knocking sound at idle, and the soot emissions have also increased slightly; however, I think that's probably normal for the mileage.
"Wear and tear repairs haven't been very frequent. The only unexpected issues were the front wheel bearings at approximately 175,000 km, and the shock absorbers needed replacing at 195,000 km. The brakes are okay; I initially had some problems with them in wet conditions, but then I installed grooved discs from ATE, and since then, that issue has disappeared."

It is definitely important to adhere to the recommended timing belt replacement intervals.
Although the service booklet specifies a maintenance interval of 120,000 km, I once heard from a workshop foreman that certain tensioner pulleys, which were installed from the factory, failed as early as 60,000 km, and that timing belts are also subject to age-related degradation. Therefore, he recommends replacing them every 4 years.
I have no idea whether this information is intended to simply boost sales, but if you follow the reports of other forum users, it seems that even in vehicles that are 5 or 6 years old and have mileage well below the recommended service interval, there can be a failure of the timing belt.
And the 5-cylinder engines are not easy to find used, nor are they necessarily available at a special price as replacement parts.

Is there a specific reason why you absolutely want to buy from "Freundlich"?

Regards,

Olli.

Hi,

First of all, thank you for the (quite diverse) reviews!
You have to expect this: You ask 2 people and you get 3 opinions .

@marko:
I was able to compare the Golf with 90 horsepower to the Audi with 115 horsepower, thanks to a test drive.
You are right insofar as the Audi feels less responsive than the Golf.
But once he gets going, he really throws himself into it wholeheartedly.
It doesn't really bother me, as I often drive on highways and prefer something more comfortable and relaxed.
I didn't find it to be slower than my Golf, though.
Thank you for your further feedback, regardless!

@olli:
I'm not very experienced with used cars, so I think the risk is lowest when buying from a dealership ('friendly,' but incompetent...).
Besides, I really liked the car I found there.
Regarding the topic of timing belts, I completely agree with your opinion:
Even on the specific vehicle I was looking at, there's a sticker under the hood that says 'Change every 120,000 km.'
However, since the car now has 105,000 km on it and had been sitting for a while, I kept insisting to the dealer until he (actually quite quickly) assured me that he would replace the belt free of charge before delivery – which is something!
I am also grateful for your information about the consumption. That is very reassuring.
With my Golf with a 90 horsepower engine, I use about 5.3 liters. An extra 1-1.5 liters would be acceptable for the Audi.

"I've been driving an Audi 100 2.5 TDI with a 'aat' engine for several years. I don't find the car to be slow or cumbersome at all. In fact, it's quicker than some lighter gasoline engines with 115 horsepower. Compared to a 90 horsepower TDI in the current Passat body style, it's true that it doesn't have as much low-end power. However, the 90 horsepower engine runs out of breath much faster when overtaking or driving at higher speeds on the highway."
The on-road performance and handling are still state-of-the-art, which is comparable to other vehicle types in the same class.
Unfortunately, I cannot provide the year of construction.
On the other hand, the brakes are not ideal: Despite all measures taken, the pedal feels very soft, the effectiveness noticeably decreases after heavy use, and ultimately, the rear calipers tend to corrode and then need to be replaced. Speaking of which: Spare parts are outrageously expensive and often not in stock.
By the way, the rear axle is not rigid; it twists during cornering and then acts like a stabilizer.

However, it remains a rigid live axle construction!
It's quite understandable that a stabilizer is needed.


Best regards: Marko

Hi,

You can also look at a simple 'carriage rear axle' in a positive light: At least it's very unlikely to break!
Besides, as someone who drives a Golf 3, I'm not exactly spoiled when it comes to the rear axle.

It's clear that modern designs are initially quite sophisticated. However, for example, with the current Passat, there are often problems due to the complex front axle.

@Christians:
What is the fuel consumption of your AAT (Automatic Air Tank)?

I must agree with the previous speaker regarding rear axle design: while a multi-link rear axle offers more comfort than the torsion beam axle of the C4 (by the way, the current A6 also only has a multi-link axle), it doesn't necessarily improve road handling (at least when the axle is not driven). However, the torsion beam axle is completely wear-free and never causes problems, making it the better choice for the average driver.
The same applies to the front axle. The C4 still has a simple McPherson suspension, but unlike the multi-link suspension in the new models, it is completely trouble-free (just look around in online forums about problems with the front axles of current Audi models; BMW also experiences similar issues...).

If you want to cover a lot of miles and don't want to buy a new car every two years, then a simpler design is often the better choice.

Best regards,

Hannes.

Regarding my AAT (Automatic Air Temperature) consumption: I bought the car 5 years ago with 110,000 km on the odometer, and now it has 222,000 km. The range is...
Between 6.0 and 8.7 liters per 100 kilometers.
Allgemein: konst. 140 nach Tacho oder einsame Landstraße in Frankreich oder Schottland: 6 - 6,5. Dauervollgas auf der Autobahn: 8 - 8,5. Landstr./ Stadt gemischt: 7 - 7,5. Durchschnitt letzte 12 Monate: 7,02. Anfangs 7,5, seit 2 Jahren bzw. 40tkm geht der Verbrauch immer mehr zurück. Ich fahre ziemlich flott, schalte aber früh hoch wenn ich nicht viel Leistung brauche: 5. Gangle at constant 65.

Regarding the suspension: around 170,000 km, the shock absorbers were worn out. However, you can replace them on the front without having to remove the entire strut assembly! At 200,000 km, the rubber bushings that hold the stabilizer bar ends in the control arms had deteriorated. Any tire shop can adjust the camber and toe alignment without needing any special tools.

And of course, the engine has a timing belt, like all TDI engines. Unfortunately, the rear (pump) timing belt broke for me after a mileage of 100,000 km. Luckily, with this belt, only the engine stops without any further damage. Perhaps those 100,000 km are only meant to be exploited by drivers who put on a lot of miles, so that the belts don't become old.

Best regards, Christian.

Regarding the timing belt:

Even for those who drive a lot, I would recommend replacing it no later than after 90,000 km. At that time, it's best to also replace the tensioner pulley, water pump, and the gear on the crankshaft at the same time. This way, you can be quite sure of avoiding damage caused by a broken timing belt.

Best regards,

Hannes.

Hi,

Yeah, the timing belt on those TDI engines really often leads to bitten fingernails, ulcers, and empty wallets.

I've definitely managed to secure the Audi 100 with the AAT engine that I mentioned earlier, and I'm scheduled to pick it up next Thursday.
Your contributions were quite helpful.
Freshly inspected (with a free inspection), new timing belts (I didn't even know the 5-cylinder engine has two!), and 2 years of TÜV (German technical inspection).
I doubt they'll replace things like the water pump and crankshaft sprocket, as Hannes mentioned. That would cost extra. Maybe, with a bit of luck, they'll replace the tensioner pulley.
I had this problem twice (!) with my Golf 3 (with 150,000 km). Thankfully, I noticed it both times before the timing belt could fail...

Hi there,

If the car still has its original timing belt, the tensioner pulley should definitely be replaced along with it.
Even if the dealer insists on an additional charge, this should be limited to the actual material costs. In particular, the tension rollers from earlier production years were not known for their durability.
The same applies to the water pump, which would also require a coolant change. It probably costs a bit more, but a broken timing belt due to a leaking or malfunctioning water pump is likely not worth the risk.

Oh yes, here's another minor weakness of the 5-series:
Oil tends to leak from the front crankshaft seal, specifically in the area where the oil pump is located, and it's often difficult to see because of the lower engine cover.
Since you're likely getting a used car warranty, I would ask for written confirmation before paying that the machine doesn't have any leaks. The repair isn't cheap, as it requires removing the oil pump and oil pan (and of course, the timing belt).

Olli.

Hi!

No, the AAT has the timing belt at the front, and only the water pump belt is located at the rear.
I've had the misfortune of this happening before, but after replacing and adjusting it myself, everything was fine again.

Best regards: Marko

Hi,

@Marko:
Ah, so! I was wondering what the second timing belt was for. After all, a 5-cylinder engine doesn't have two camshafts.
I only have a somewhat basic understanding of the 1.9 TDI engine.
But I'll eventually get to know the 2.5 engine – first, I'm going to buy a repair manual on eBay.

@olli:
Thank you for the tip about the tensioner, etc.
I immediately inquired about it – the tensioner roller was going to be replaced anyway (at least at this particular workshop).

Marko wrote:

No, no, the AAT has the timing belt at the front, and only the water pump belt is located at the back.

Great progress... it was already like that with the 5-cylinder pre-combustion chamber engine (2.1L, 75 hp) .

Hi,

@Bertil:
...however, the pump is not misaligned in that case, and if the main timing belt breaks, the engine will be damaged...