2004 Audi S4 Avant, Engine Repairs
Mark: Hi, it's Mark from Top Local. I'm here with Bernie Pawlik, Pawlik Automotive in Vancouver. Vancouver's best auto service experience. 22 time winners of best auto repair in Vancouver as voted by their customers. And today we're talking about a little hot rod an Audi S4, 2004, that had some engine problems. What was going on with this vehicle Bernie?
Bernie: This is a regular client of ours and, he was driving the vehicle all of a sudden the engine started running rough and he brought it straight to us for us to look at. So, yeah, basically rough running engine happened just suddenly.
Mark: So this is an an S4, so this is the very hopped up version or the next to the most hopped up version of an Audi that you can get. So what engine is in this vehicle in 2004?
Bernie: This one has a V8 engine, 4.2 litre V8 engine shoehorned, literally shoehorned into the engine compartment. I mean, the car is basically an A4 they've managed to cram a V8 engine into it. There are not many things that are easy to repair on this vehicle. Spark plugs are easy to replace. The intake manifold can come on and off easily. It was a few things, but most things are extremely difficult to service on this vehicle.
Mark: So what testing and diagnosis did you perform?
Bernie: So scan the vehicle computer, found some codes for engine misfire and multiple engine misfires. And then from there, it was a matter of, you know, based on how it was running to test the compression. We found that one of the cylinders, and I'll be honest with you I believe it was number two, but for some reason, the car was here for a long time. So one cylinder had no compression in it, so at that point we realized, okay, it's either the timing chain may have skipped the tooth and some valves got bent or something has happened that we've lost compression in that cylinder. The engine has got to come out. We've got to dismantle it and figure out what the next issue is.
Mark: So what was involved in repairing the vehicle?
Bernie: Well, it's an awful lot. As I mentioned, the engine's shoehorned in. Taking the cylinder heads off is impossible, but cylinder heads are the thing that we need to take off to see when there is piston damage or valve damage, or what's caused the no compression.
So, in order to remove the engine, it's typical on Audi's when we need to do a lot of repairs, the front bumper assembly, and radiators have to come off. A lot of times you can put it in a service position, but we need to take everything off because we're taking everything out. The engine and transmission and subframe are dropped down below the vehicle.
It's many hours of work for a move everything. But once that's done, then the engine and transmission can be separated again, quite an elaborate job on this thing. You know, everything is fitted together so precisely. There's very little room for anything. So that was our next step.
We pulled the engine and then from there, proceeded to remove the cylinder heads again, extremely involved amount of work, to get the heads off because this engine has a very elaborate timing chain mechanism, which you'll see in some pictures that I'll show you. But once we get the heads off and we found, our problem, and that was one of the valves had dropped slightly due to a broken valve spring.
And, that's basically what caused our problem. The valve spring broke. The valve dropped and lost compression and it got slightly bent. Fortunately for the customer, that's all that happened. He brought it in soon enough and there wasn't any further damage. Let's just go into some pictures right now because that shows a lot.
So this is on the left bank of the engine, second cylinder from the front. You can see a mark here. This is one of the intake valves is tapped, just tapped the piston. Fortunately no further damage happened otherwise it would have required a complete engine overhaul or replacement.
Here's a view of the cylinder heads. These are five valve engines. There's three intake valve, two exhaust valves, nicely circling the spark plug. And this of course was the valve had the broken spring. So as part of the repair, we sent the vehicle to the machine shop for a full cylinder head overhaul, and they replaced all the valve springs because you never know if one breaks when's the next one going to go. So that's what we did for that particular part of it. So these are the heads basically reconditioned and resurfaced and ready to be installed.
So as far as other issues, problematic areas of this engine we can get into next. Timing chains, I mentioned they're very elaborate. And, I'll just show a picture, this is a partial view of the timing chains, these are at the back of the engine, between the engine and the transmission.
Now this there's only a partial view. And this, you know, when I see these pictures, actually I'll just, we'll just cut to the full view because it's really mind blowing. This is the timing chain assembly on this vehicle. There are one, two, three, four timing chains, just an array of guides, tensioners on each chain. And guide failure is very common on these engines and so hence timing chain failures. And on this engine, we replaced all the guides and the tensioners, the, actual chains themselves don't tend to wear, but the guides do, and once they fail, they're, you know, the plastic pieces, they eventually chip or break and, you know, because of timing chain failure.
So you can see if you just take a moment, I'll just leave this picture up for a while and just look at all the things that are driven. So this is the crankshaft here, which drives this assembly here. This is an accessory drive assembly. And I'll show you a view of what that drives afterwards. It drives the air conditioning compressor from this unit here. So this is again, exceptionally complicated. And when I look at it, I go, I mean, let's put an electric motor in. I mean, it's just, you know, one rotating shaft versus like these zillions of pieces. I mean, it's amazing how well this works, but there's just so many moving parts to go wrong.
Anyways, so this is a common problematic area on this engine, the timing chain. And if you do have one of these with the V8, they will give you a problem at some point in time.
Mark: Yeah, that's a lot of plastic with a lot of friction and a lot of heat on it.
Bernie: It really is. And you know, when people, you know, don't change their oil regularly, you know, get kind of lazy, it's just, you're just asking for trouble. Even if you do all your oil changes on time, they'll probably still be a problem that develops just because of the type of engine. But anything you can do to keep it lasting longer is so critical and so important. So, you know, skimping on a lot of changes will wear these plastic bits and pieces out way faster. So it's just so important to do them on time or earlier.
So, couple of other issues we found with this engine. As we took it apart, we noted a bit of fluid seepage coming out between a couple of seals. So this is a view of the front of the engine reassemble. And you can see here, there's a case casing here. There's a lower oil pan casing. Again, you know, it's like exceptionally complicated machinery. Casing here, casing there, this goes all the way around. This is basically the main engine bearing casing. What we found, looking at the side of the engine. I don't have a picture of a before picture, but there was some, you could see some coolant seepage, very minimal, but nonetheless this engine was out, it was time to really, it was either do it properly or, with, you know, great extra expense. But at a later date, you'd have to pull everything back out that we already pulled out to do this. So it made much more sense to tackle this. So here's a view by the way, I mentioned the accessory drive from the timing chain. This is the air conditioning compressor, which is driven by a shaft from the timing chain with a nice little CV type joint coupling. And so again, like more complexity.
And here's a bottom of our engine. So this is before we removed the main bearing case, we can see some seals here that were leaking. And then if we look further down into the engine, this is what the main bearing case cover off. Again you can see more O-rings and seals as one here, one here, one here. You can see the seals kind of starting to fester, bubble. So these were all replaced and, you know, a lot of extra labor and work. There's special sealant around all these other areas and the O-rings, of course needed to be replaced.
This is a closer view of the upper case. This is the main bearing case, I guess you'd call it. And again, the number of seals here, I've just put arrows pointing to all of these seals and O-rings. All places for leaks to happen and they were all starting to leak. So in 2004, this vehicle's now 16 years old. So this is the kind of time where all these things start to go. And I think that pretty much concludes the picture show.
Mark: Okay, this sounds like an enormous job. And with all that time, it's going to be expensive. So was it worth doing it on this car?
Bernie: Well, the owner likes the car, he loves his vehicle. So for him it was worth it. I don't know for everybody, whether it is, it really depends on how much you liked the car. Yeah, that's really, what it comes down to. How you value the car. Some people are really about Hey, you know, this car's worth X amount of dollars. I'm not spending any more than that, or I'm not spending half the value of the car. People have their formulas. Other people are like, you know, whatever, I love this car. I don't care what it costs to fix it. So it wasn't that he didn't care, but you know, it was, he was committed to fixing this one.
Mark: And how did the Audi run after all this repairing work was done?
Yeah really awesome. Yeah. Ran really well. Nice, smooth running machine and should be, you know, fingers crossed, there should be no fluid leaks. And certainly from any of the parts that we replaced and resealed, you know, those are all things that are good, preventative measures and maintenance for the future.
And a lot of power from a normally aspirated engine, but a relatively huge engine in a small vehicle, basically.
Bernie: It is. And I mean, it's a beautiful engine. You can see the five valves, you know, the valve timing gear. I mean, it's really well built. It's only a 4.2 litre, which is not that big, but it's still, you know, compared to the normal 2 litre turbo that would come in the car, it's a really nice instant response power machine. It's really fun to drive and all wheel drive in a wagon. You can haul, your kids around and, you know, have a nice little sports car and sort of some bikes on the roof. It's a practical sports machine.
Mark: So is this, after all that said and done, is this a vehicle you would recommend for someone to buy?
Bernie: Well, I'd say with great deal of caution. One thing I was going to mention, you know, is that in the same week that this customer came in, we had another client who had just bought one of these cars, love the car. He just bought one and came and had it towed in. He was on a road trip and the engine basically conked out on him, towed it in. We looked at it and I think the same thing happened to his engine. Only he was probably going at highway speeds and, it just, as far as we got with the diagnostic, we pull one spark plug out of a cylinder and a whole electrode on the end was just pounded right off. So I believe what happened for this particular engine is a valve spring probably broke as well and, dropped the valve into the engine and, you know, just bent everything up.
So for him, there was a little more work you involved in terms of replacing, well replacing it with a used engine was what we came up with, but he chose to have someone else to do the work on it. But again is it worth it? You know it really depends on the individual. I think if you're going to buy any of these Audi V8s, you know, there's a few cautions to look at. Things like, timing chain failure is common. You know, those timing chain guides fail. Also now, you know, having had two vehicles in a week with probable valve spring failure, is that looks to be like another common problem as the engine ages. So I think it's something to keep in mind.
I think with any car, you know, if you buying anything fancy, just expect that, you know, something or anything could go wrong and it could be expensive to fix. But there's some engines that clearly have a better track record over time and are built more robustly. I think this engine is not quite as tough as it could be and it's exceptionally complicated. So, that's something to keep in mind, but if you love this car, you know, it's your dream, buy it.
Mark: If you have an Audi in Vancouver and you need some repairs or you just want basic maintenance and common sense maintenance procedures and information about what you need to take care of and what you can leave, the guys to call are Pawlik Automotive. You can reach them at (604) 327-7112. To book your appointment, you gotta call and book ahead because they're busy. They're always busy. Best shop in Vancouver. Check them out at pawlikautomotive.com. Or there's a YouTube channel where we have hundreds of videos on there, Pawlik Auto Repair. And of course, thank you so much for watching and listening. We really appreciate it. Leave us a review and thanks Bernie.
Bernie: Thanks Mark. And thanks for watching.