I'm Bored… but I have an '89 Audi Coupe Quattro 20V and a factory manual

[pscouto]

So... I'm 40 and bored.

My dad bought a 1989 Audi Coupe Quattro 20V brand new. It has about 286,000 km now. It was always more of a weekend car since he used a company vehicle for work. After I got my license, it became my weekend car. It was cool enough to impress my school friends and comfy enough for dates—so yeah, lots of memories in that coupe. It’s always been special to me.

Now back to being bored. I'm an IT guy with just basic experience—oil changes and light maintenance on modern family cars. But one day, I picked up a workshop manual, found the factory manual online, and since I had time on my hands... I started reading. A lot. I went down the rabbit hole: tools, parts, forums, YouTube videos like they were pepperoni pizza.

At this point, I’m confident (sort of) that I can actually do something meaningful with the car. I should mention—I’m in Portugal, and this car/engine combo is rare here. So pretty quickly I realized: I’d rather take the risk and work on it myself than trust a random mechanic who might not even know what it is.

About the car: it has the NM engine, basically a 2.0L version of the 7A (thanks to our lovely tax system). It's slow as hell, has no torque—but it wasn’t always like that. I suspect a mechanic messed things up years ago. My dad remembers the engine having issues; the first garage couldn’t get it running, and it ended up at a second one. After that, the car never felt the same. He rarely drove it after that. I used it more during college, but I never really knew how it was supposed to drive—it was always sluggish, thirsty, and loud... though the exhaust note is fantastic.

The car has been parked for the last 5 years. Before that, it started fine, didn’t overheat, and didn’t smoke (no blue/white exhaust). Before doing any serious work, I took it to a shop to change all the fluids, timing belt, water pump, and thermostat. After that, I took it for a gentle drive... and it overheated.

I didn’t suspect a blown head gasket at first, so I started inspecting the cooling system. The expansion tank was brick orange—not from paint, but from rust and tap water. No coolant. The rubber hoses looked okay on the outside but were full of hardened particles inside. I managed to clean and reuse them. I flushed the system with a ton of distilled water, cleaned both radiators, and used a bit of Evapo-Rust to help clear things out. I tested the thermostat in boiling water—working fine. Checked the water pump—it spins freely.

With the engine running, I checked the bleeder hose going to the heater core—water was circulating. But the radiator fan wasn’t kicking in. I figured it might be a bad sensor. Fuse was okay, and the fan spun when I jumped 12V directly to it. Wiring checked out too (as far as I could tell).

At this point, I wanted to be sure: Is the engine overheating because of a blockage or a bad head gasket? I bridged the fan switch so it would run at full speed and cranked the cabin heat to max. Hot air came out, and the coolant was circulating… but the engine still overheated. Not a good sign.

Oil looked fine—no milky residue. But I used a combustion leak tester in the expansion tank and… yep, it changed color. Great. Looks like I do have a reason to open the engine now.

Following the manual, I opened the valve cover and discovered the camshaft timing marks were off—one or two teeth. That could explain the poor performance, right?

Then I read up on the fuel pump relay fuse—the one that changes ECU behavior. Turns out my car had a fuse there… and probably always did. That’s not supposed to be there, right?

Next step: remove the exhaust manifold. I’ve already hit the bolts with WD-40 and letting it soak.

Any advice or tips are welcome. Also, sorry if my English isn’t perfect—I'm doing my best.


Thanks!
Pedro

[K Simmonds]

I like your title...

If it's failed a coolant dye test then I'd be 99% sure you have a head gasket leak, especially with the overheating symptoms you describe. It sounds like you have a leak between a cylinder and the water jacket pressurising the cooling system.

Personally I always do a leak down test before I remove a cylinder head just to be 100% sure, but I don't expect a home mechanic to have a test kit.

Have you got an air compressor? If you have then a Chinese knock off of a Sealey kit is under £20 on eBay or genuine one is over £50.

I've never driven an NM engine CQ but have had a good go in a 7A car and thought it went very well, can't imagine the NM is much slower.

The timing marks inside the cover really shouldn't be off at all. The only way the mark's on the cam sprockets can be out of sync is if someone has been in there and had the cam's out for some reason. With the cam cover on do the exterior timing marks line up okay? The timing being out would certainly explain the poor running.

There should be no fuse in the pump relay unless checking something, I think the ignition timing but I'd have to look that up myself.

As for general advice, take plenty of photo's of of where things go as you take it apart and take your time, if your not sure about something the factory manual will tell you.

Your English is fine BTW.

[Tractor Dave]

Even though you have been around as long as me, only two posts so, welcome.
These engines are not difficult to work on. Get the Haynes 80 manual as it covers the 20v engine. Follow the steps methodically and take your time. Get a local machine shop to test and skim the head after you have stripped it. Make a sectioned box so you can put all the parts in marked holes and replace everything where it came from. Get a good quality head gasket set with all the upper gaskets and oil stem seals plus new head bolts. Reinz are good. Be meticulously clean. Replace the small chain between the cams. If the car has been well maintained, i doubt the bottom end will need any attention but check the bores for wear while you are there.

[K Simmonds]

As Dave's says cleanliness is really important, I vacuum clean my workshop and bench a couple of time's before opening up an engine or working on a head.

Also as he says it's vital all components go back were they came from, especially the cam caps, these must go back in the same location and orientation. And whatever you do don't loose one, so a labeled box/tray is a really good idea.

That engine actually looks very clean inside for it's age and kilometers so has obviously been pretty well maintained oil change wise, though at 280K the exhaust valve guides may want replacing whilst it's apart. The valve stem oil seal's are a bit of fun to change and you'll need a valve spring compressor to do them along with a good dose of patience.

In some regards Haynes manuals are actually easier to follow than the factory manual and do fully cover the 7A/NM engine.

If you're at all stuck just ask on here and one of us will be along to help.

[pscouto]

First of all, thank you for your time and words of wisdom — I owe you all a beer!

I use the Haynes manual (hardcopy), but I found that the factory manual has extra information and diagrams that seem important. It's also a PDF, so it's easier to search. I’ve been using both together.

I bought this tool to check if the block is straight:
https://www.bgstechnic.com/en/Produc...ge-600-mm.html
And I also got a thickness gauge. I saw this method in this video:
https://www.youtube.com/watch?v=JFcwr17JuRg

The gasket kit I bought is from Autodoc ajusa, the same brand that made the video… fingers crossed it’s not some cheap rubbish.

The small chain between the cams doesn’t look loose — should I replace it anyway?

For the valve stem oil seal's i bought a kit on amazon ( see photo)... lets see if is enough to do the job

Last night, I tackled the exhaust manifold. Do I need to fully remove it, or is it enough to just detach it from the head? (see photo)

Also, how do I remove the bolt from the camshaft gear? Should I get the VW544 tool?

I took some pictures of the camshaft gear showing the timing marks. Let me know if it really looks like it’s out of sync.

[pscouto]

I´m recording what i do with a head camera... Also taking lots of pictures before removing something...

[Pibbow]

Following this as I may need to do some open heart surgery on my ABY later in the year.....

[K Simmonds]

It does look like the cams are a tooth a out but it's really hard to tell from the photo's. Though how this could happen is a bit of a mystery, I guess one of the garages the car was at could have been in there and pissed about. However, after working on these engines for over 20 years nothing surprises me these day's, I've seen some awful work done by other mechanics, including so called specialists. It would also explain the poor performance.

Can you get the marks to line up carefully using a spanner on the end of the exhaust cam? And did you you put the engine on all it's exterior timing marks including the flywheel before starting the job? This is really important, though it looks like you did from the position of the cam lobes.

The exhaust manifold can stay in place, I'd get it pulled over to the left as far as you can using a large cable tie or bit of wire so there's no danger of the studs in the head catching it whilst your lifting it off and more importantly back on.

You should use a muti fit sprocket holder to stop the exhaust cam moving whilst you undo the bolt. To remove the sprocket undo the bolt a couple of turn's then give head of the bolt a light tap with a soft face hammer, this normally loosens the sprocket first time.

Yes, I'd fit a new cam chain on 280K Kilometers.

The kit you've purchased is designed for changing the stem seals with the head in situ using compressed air to keep the valves your working on up, you'll struggle to do them with it once the head is removed. And it's extremely difficult to do the job with the head on due the top of the valves being deep in the head.

What you really need is one of these...

https://www.ebay.co.uk/itm/205184698...BlBMUI692ojSZQ

This is a multi fit sprocket holder, though don't pay that much, it's just the first one I found on eBay.

https://www.ebay.co.uk/itm/186931399...Bk9SR-Ll9YjSZQ

[Tractor Dave]

Ajasu head gaskets are apparently quite good. Japanese car forums like them.

[psiconauta911]

Hi and welcome, I´ve had one of these in the past and now have a 90 with that same engine 20V quattro (NM), they aren´t the most powerfull engines on earth but are quite strong after 4500rpm.
Where are you from?

[pscouto]

It does look like the cams are a tooth a out but it's really hard to tell from the photo's. Though how this could happen is a bit of a mystery, I guess one of the garages the car was at could have been in there and pissed about. However, after working on these engines for over 20 years nothing surprises me these day's, I've seen some awful work done by other mechanics, including so called specialists. It would also explain the poor performance.

Can you get the marks to line up carefully using a spanner on the end of the exhaust cam? And did you you put the engine on all it's exterior timing marks including the flywheel before starting the job? This is really important, though it looks like you did from the position of the cam lobes.

The exhaust manifold can stay in place, I'd get it pulled over to the left as far as you can using a large cable tie or bit of wire so there's no danger of the studs in the head catching it whilst your lifting it off and more importantly back on.

You should use a muti fit sprocket holder to stop the exhaust cam moving whilst you undo the bolt. To remove the sprocket undo the bolt a couple of turn's then give head of the bolt a light tap with a soft face hammer, this normally loosens the sprocket first time.

Yes, I'd fit a new cam chain on 280K Kilometers.

The kit you've purchased is designed for changing the stem seals with the head in situ using compressed air to keep the valves your working on up, you'll struggle to do them with it once the head is removed. And it's extremely difficult to do the job with the head on due the top of the valves being deep in the head.

What you really need is one of these...

https://www.ebay.co.uk/itm/205184698...BlBMUI692ojSZQ

This is a multi fit sprocket holder, though don't pay that much, it's just the first one I found on eBay.

https://www.ebay.co.uk/itm/186931399...Bk9SR-Ll9YjSZQ

Returned the kit for chaging the stem seals and bought what you recomended and the sprocket holder. Monday are here so no work until then... Bored again...

[pscouto]

Hi and welcome, I´ve had one of these in the past and now have a 90 with that same engine 20V quattro (NM), they aren´t the most powerfull engines on earth but are quite strong after 4500rpm.
Where are you from?

Ora viva. I´m from Penafiel, near Porto. And you?

[Tractor Dave]

Have you got the proper tool to lock the damper and remove/tighten the bottom crank pulley?
never use a rattle gun on that bolt or the top pulley bolt. It damages the keyway.

[K Simmonds]

Returned the kit for chaging the stem seals and bought what you recomended and the sprocket holder. Monday are here so no work until then... Bored again...

There's nothing stopping you from lifting the head with the cam's in place, the cam sprocket bolt isn't that tight and can be undo on the bench with the head on it's side. It is however, easier to do with the head still bolted down.

You must use a proper locking tool to tackle the 27mm crank bolt, this is super tight or at least should be 450nm. I strongly suspect you'll find the key-way on the on the bottom cam belt pulley has been cracked by a previous mechanic tightening the bolt up with an air gun causing the timing to slip, it would explain why they've then been inside the head and pissed about with the cams. I always replace the this pulley ideally with a billet one.

You'll need a 3/4" drive breaker bar and deep 27mm impact socket to undo and tighten and crank bolt, 1/2 drive tools simply won't cut it for this job.

I use an impact socket as there's no danger of that breaking or slipping. As Dave said don't use an impact gun on this bolt, it will break the key-way on the cam pulley.

I'm doing the belt on a 7A on Monday so will try and remember to take a couple of photo's to show you how to do it properly, or at least the way I do it which is pretty much by the book.

[pscouto]

There's nothing stopping you from lifting the head with the cam's in place, the cam sprocket bolt isn't that tight and can be undo on the bench with the head on it's side. It is however, easier to do with the head still bolted down.

You must use a proper locking tool to tackle the 27mm crank bolt, this is super tight or at least should be 450nm. I strongly suspect you'll find the key-way on the on the bottom cam belt pulley has been cracked by a previous mechanic tightening the bolt up with an air gun causing the timing to slip, it would explain why they've then been inside the head and pissed about with the cams. I always replace the this pulley ideally with a billet one.

You'll need a 3/4" drive breaker bar and deep 27mm impact socket to undo and tighten and crank bolt, 1/2 drive tools simply won't cut it for this job.

I use an impact socket as there's no danger of that breaking or slipping. As Dave said don't use an impact gun on this bolt, it will break the key-way on the cam pulley.

I'm doing the belt on a 7A on Monday so will try and remember to take a couple of photo's to show you how to do it properly, or at least the way I do it which is pretty much by the book.

Yeah, I was considering that, but the socket I had for removing the head bolts was rubbish, so I picked up a stronger one. Also i´m cleaning everything before taking the head out.

As for the crank bolt, I read about that issue, so for manual extraction I was thinking of trying this method: https://www.youtube.com/watch?v=znfR69UdDKs

What did you mean by “billet pulley”?

I'm not sure about something—I think the first cylinder is at TDC, but what could go wrong if it isn’t when I remove the head?

Thanks!