Tagged: Audi B5

1998 Audi A4 quattro Avant – 250,000 miles and still counting

My 1998 Audi A4 quattro Avant (station wagon) crossed 250,000 miles few weeks ago and while it is still going strong, it does need some attention. This car is the 2.8L 30V 5-speed configuration (2.8 litres displacement, 30 valves, yes, that means 5 valves per cylinder, and 5-speed manual transmission). I started working on the suspension last year and got the rear springs and shocks replaced, I have the new front springs and shocks, but have not had the time to fit them. Oh, yeah, the springs are the Vogtland 35mm lowered sport spring set and the shocks are Bilstein Sport. So the car has been riding lower in the rear than the front since last December. It has needed a new clutch for the past 20,000 miles, I just keep nursing it along. The subwoofer in the cargo area in the back needs to have it’s foam surround replaced. I have a set of steel brake lines to replace the six short rubber hoses. Nothing major …

After meeting with my mechanic a few weeks ago we identified a couple other things the car needed. The first order of business was to address a very slight mis-fire at low speeds and under heavy load. My guess was spark plug, wire, or ignition coil pack as low speed and heavy load put the highest demands on the ignition system. The car was not showing any ignition related fault codes, and my mechanic said that any ignition coil fault would set a fault code. He also flagged that the valve cover gaskets were leaking and letting oil seep into the spark plug well and contaminate the plugs.

So this weekend I tackled the valve cover gaskets / spake plugs / plug wires and general cleanup. I also replaced the cracked brake fluid reservoir.

Here is how it looked after I had removed the air intake and air filter. I had not bothered to take a picture before I started any of the work, this was to help me put it back together if I needed it. You can see that spark plug #3’s wire is disconnected from the ignition coil.
Once the rest of the airbox and cables and hoses were removed,
I was ready to pull the right side valve cover.
Looking down at cylinder #3 you can see:
1. the pool of oil at the bottom of the spark plug shaft in the middle
2. the 3 intake valve cam lobes at the top
3. the 2 exhaust valve cam lobes at the bottom
4. the chain drive that connects the two camshafts for this bank on the left
Here is the entire right hand side head as viewed from the top.
Note the two fuel lines disconnected at the top left, one is the high pressure supply and the other the return from the fuel pressure regulator. I could not get the valve cover past them without disconnecting them.
And here is the left hand side.
Both sides open to daylight. Note that the designation Left side and Right side are from the driver’s seat, so the RHS is on the left in this photo and the LHS is on the right.
To get the LHS off I had to move the coolant reservoir, there is enough play in the 20 year old hoses to just move it aside once the three screws and one electrical connector are un-done.
Where did the brake fluid reservoir go ?
The white blob to the right is the new one.
There are four connections to the reservoir:
1./2. two connections to the brake master cylinder, front/rear
3. the blue lined hose just right of center is the connection to the clutch master cylinder
4. an electrical connection for the brake fluid level float
(yes, the car tells you if you’r brake fluid level is low)
This reservoir of brake fluid is also the source of the
clutch fluid necessary for the hydraulic clutch.
That is the new brake fluid reservoir installed. Since it is a “universal” part, good for manual or automatic transmission cars, I had to cut an opening at the end of the fitting for the clutch feed. Not a big deal, if you noticed before you installed it.
The other part of this project, the ignition coil module.
The black connector at the right is where power comes in and each of the three coils are signaled to fire. The silver brick with the fins is the electronics module that fires the coils. Each high voltage ignition coil, there are three of them, has two outputs. Unlike old school coil plus distributor, none of these coils have a ground connection on the output. The two outputs go to opposing spark plugs.
Getting technical here, each spark plug will fire twice for each pass through the 4-cycles of a modern engine. Both times at about top dead center, once when going from intake to compression stroke, and again at the “other end”, when going from exhaust stroke to intake stroke. A clever bit of efficiency if you do not need to tune each spark individually. Current ignition systems usually have one coil per spark plug to permit just such monitoring and tuning.
This is the bottom of the module. This is as close as you can get to the guts. Each coil is epoxy potted and the electronics module is encapsulated in what feels like rubber. Given that this example is still performing flawlessly after more than 20 years and 250,000 miles I’d say the assembly technique works well.
Having said that, I did not like the look of the rust on the iron laminations on the ignition soil cores, so I took to cleaning, priming, and painting it.
In this case, assembly really was the reverse of disassembly.
Everything went together very smoothly.
LHS valve cover replaced.
But I had to then remove the coolant reservoir again (thankfully it is only 3 screws and 1 electrical connector) to get at the spark plugs to replace them.
RHS valve cover back in place.
A side note about electrical connectors and connections.
Many mechanics and cars use grease to keep water away from electrical connections.
Keeping water away is good, but the grease does nothing to improve the electrical connectivity. Most, if not all, electrical connectors on Audi’s (and probably VW’s and Porsche’s as well as other German manufacturers) are designed to keep the water out. So I worry less about water and I do worry about the electrical contacts themselves.
DeoxIT is a chemical that cleans and lubricates electrical contacts, leaving a film behind that improves conductivity. I use it on every electrical connector as I reassemble things.
I also use it on mic packs in theatre, but that is a different category of discussion.
There was one casualty of the job. A small capacitor installed adjacent to the Ignition Coil Module was damaged while removing the Ignition Coil Module. A small blob of epoxy and it is back in service (note the shop towel to catch any drips as the epoxy sets).
Here is the freshly cleaned, primed, and painted Ignition Coil Module reinstalled at the front of the engine with a brand new set of spark plug wires. Note the repaired capacitor at the lower right hand mounting bolt.
The whole thing put back together.
I do not generally use the plastic cosmetic trim covers, while they make the engine bay look cleaner, they serve no really useful purpose and just get in the way when you need to do something.

Replacing the rear springs and shocks was the first major automotive project I have done in years. This is the first major project under the hood of this car, even though I have owned it for well over 10 years and 100,000 miles. Up until now I did not have the luxury of working leisurely on this car, we needed it for our daily commutes, so any work went to the shop and we got a loaner. Having said that, there has been very little that needed to be done to the engine.

The next items are a mix of general maintenance and projects.

  • The air filter needs replacing
  • It is due for an oil change
  • I need to find a rubber surround for the subwoofer
  • The front suspension is calling me
  • Those brake lines are not going to replace themselves
  • But I will pay to have a professional replace the clutch, anybody know where I can get an affordable lightweight flywheel / clutch kit for a 1998 A4 (B5 chassis) 2.8L 30V 5-speed quattro Avant ?