Guide S4/A4 V6 Cambelt

[spellmaster]

Guide to replaceing audi A4/S4 cambelt

OK first off lets get the disclaimer out of the way. I accept no responsibility for any damaged that could occur as a result of following these instructions. They are not designed to replace intelligence and common sense. This is merely a guide to how I successfully changed my cam belt. If you do not have the experience / tools or inclination please only read this as a guide to what should be done by a pro mechanic.

Ha! Right now that’s out of the way I thought I would post an article on how I replaced my cam belt on my B5 S4 2.7 Twin turbo. Note that much of this process will be the same as any B5 V6 cam belt replacement, on the S4 you just need to remove more bits!

So the story starts a few months back when I purchased my S4, I soon discovered that it took absolutely ages to warm up. I quickly surmised that the thermostat was at fault and needed replacing, a simple task I thought to myself. Indeed on every other VW/Audi car I have ever owned replacing the thermostat is a synch.

However Audi in there infinite wisdom decided that on the V6 engine they would tuck the thermostat in behind the cam belt! Nightmare! Starting to see why the last owner didn’t get it done. A trip to my local Audi dealer confirmed my suspicions, they could do the job for; just £1000 :O!

Being the sort of person that has cars in bits all the time I decided that it would be more beneficial to my bank account that I did the job myself. Still which ever way you cut it this is not exactly a cheep job.

Checking my service history I found that the belt had been replaced very early on at only 42,000 miles due to a noisy water pump (early w-pumps were engine killers on these v6’s) this was now 5 years on so I decided that everything should be done whilst I was at it.

I recommend that every part that is replaceable should be done at the same time, otherwise you will find yourself back there again at some point.

So here’s a list of parts you should look to replace when doing this job. I would recommend purchasing genuine parts, again it’s probably a false economy not to:

Cam belt (der!)
Auxiliary belt
Cam belt tensioner
Cam belt tensioner damper
Cam belt roller
Water pump + gasket
Thermostat + o ring
Rad pipe clips
Rad temp sensor
Coolant

I also chose to change the oil, filter and pugs whilst I was there therefore add the following:

Sump plug
Oil Filter
Platinum spark plugs
6 Ltrs of oil

All this will probably set you back £350 odd. Now at this point ask your self if you have had a quote from an independent garage of around £400-500 to do this job ask them specifically what bits they would change for that price.

So here they all are then laid out on my garage floor.


Now check them! My darn audi dealer gave me the wrong auxiliary belt, there are several types depending on the specific V6 you have so it’s always worth checking against what your taking off or on www.vagcat.com.

You should also not in the picture are the two special tools you need for this job. The cam locking bar and the smaller crank locking bolt. I would say that both these tools are essential and can be obtained from ebay and other places for less than £100.

Bumper, Headlights, washers & misc trim
As with most mechanical jobs the longest part of this job is actually removing all the parts necessary to access the cam belt. This mostly involves unbolting many, many items.

The first item to remove would be the under tray, get the car in the air and supported on stands. The under tray is held on by three screws at the front under the bumper, and then three at the back of the tray. There are also two plastic screws in each wheel arch, if the car has been looked after they will still be there! Then there are two self tappers in side each wheel arch holding the inner wing to the bumper.

Now the front bumper can be removed. There are a couple of variations here but the main bolts are in the same place. For the S4 bumper, the intercooler intake grills need to be removed there are two clips on the inner part of the grills, put a screw driver in and then pull them off, they should unclip fairly easily. If you have fogs you can try unclipping them now, if they don’t play ball then there is some slack to remove them as your taking the bumper off.



This exposes the two main bolts that hold the bumper on, Un-bolt them. Now you must pull the bumper off its side clips, and ensure it is free of the inner wheel arch on both sides. Have an assistant help you off with the bumper, it is not heavy, but if you like me have headlight washers you can easily damage the pipe work so take care.
Once the bumper is half way off; you should see the pipe for the washer system. There is a coupler in the line so remove the black clip and uncouple the pipe. Have a bucket ready to collect you washer fluid, umm Audi lemon fresh….



Once the bumper is off on the s4 you also now need to remove the intercooler air guides, one small bolt on each, although it also has a screw head don’t be tempted, use a socket as it will be much less likely to damage the screw.

Now its time to remove the headlights, again take care as the lights have feeble plastic mountings and can break. Each light has four bolts, two on top, one hidden in the wing and one underneath. The one underneath actually doesn’t need removing as it is a steady so the light is pushed in. However if you don’t unbolt the steady you must remove the light with a side ways action, don’t pull it out the front or you will break it!

Power steering & Air con
There is a small circuit for power steering cooling just below the fan. This can be simply unbolted (2 10mm bolts) and tucked out of the way under the car.
Next is the air con. It is possible to remove the air con rad, with out draining the system, the pipes have a lot of slack for this reason, however do inspect your pipe work if you are in any doubt about its condition then have the system drained, this is a pro job as the gas will boil at room temperature so think what it will do to your skin!

If all is well then unbolt the front fan, then the rad. The rad Is held in rubber mountings at the bottom so you can un bolt then lift it out. Now move it to the side. For convenience I put the fan back on the mountings.

Radiator & Front panel (lock carrier)
Now were almost ready to remove the front panel completely. Unclip the top and bottom radiator hoses. These have crappy clips on that will probably fall to bits when you remove them, so get some new ones. Remove the trim around the power steering reservoir you will find a whole load of connectors. Un clip all the connectors going towards the front panel, there will probably be some cable ties on the way too.

Now unbolt the two bolts that attach the front panel to each wing on the top of the front panel (4 in total). There are two additional bolts under the indicator. Then there are 8 bolts that sit by the bumper brackets. Remove them all.


Boost pipes, Viscose fan & aux belt


So from the picture you should now see were getting somewhere. Not I have been lazy and not disconnected the pipes for the gearbox cooler. Do this if you wish I took the view it was not necessary and supported the front panel to ensure there was no strain on the pipes.
Note on my S4 I have an APR inlet (the blue pipe) this is ally all the way to the throttle body, eliminating the troublesome rubber Y pipe. The removal for this part is therefore slightly different from the factory part, all simple stuff really.
With that out of the way we can press on and remove the viscose fan, I chose to remove the plastic fan from the ally centre part. I must say this was probably the most awkward part as the fan has a reverse thread and must be held tight whilst you un do it.
Fortunately the pulley has some holes in to put a tool in to so you can hold it in place, I had to make up a little tool that would do the job so you may want to get hold of a nice set of angled pliers.
With that done you can then remove the large bottom pulley and all the cam belt covers.
The viscouse fan pully with then need to be completely removed. A good set of keys come in handy hear as you will need to undo some bolts that are behind the pully, these can be accessed by turning the pully so the holes expose the bolts. See pic




Steering pump, cam locks, crank locks
To access all 9 bolts on the water pump unbolt all the bolts that hold the power steering pump in place. There is one bolt that hides on top of the pump under the left hand side of the throttle body. It’s a bit tricky to get at, a good hex key and tool set help here.


Get the locking tools ready and turn the crank the direction of normal engine rotation (do NOT turn it the wrong way, this could damage the variable valve timing parts in the heads).
It should be obvious that the cam lock inserts in to the holes on the cam in only one orientation. As the holes are different sizes. If it doesn’t go on then turn it a further 180 degrees.
Note I chose to leave this locking bar on for much of the time. However the cams are at rest in this position so don’t worry if it falls off when you’re doing something else, the cams will not spin round.
Now the crank lock is next locate a small bung held in by a 10mm bolt on the right side of the engine. Just behind the air conditioning compressor. Remove the bung, you may get a little oil out too. Now insert the locking tool and tighten. Ensue that the crank is locked by gently trying to move it. Everything should now be locked up.


Water pump, tensioners, idlers & cam belt
If you have a Bentley work shop manual you may have read through the recommended way to replace the belt, which involves unbolting the cams by 5mm and pulling them free. I was very uneasy about doing this as it seemed to make no sense to lock the cams then unbolt them. (probably why they now lock the cams differently on the new engines). Anyway this step is simply done to make life a little easier when tensioning the new belt, it is not essential. However take great care when installing the new belt. There must only be slack on the belt between the crank and the left hand cam.

Remove the old belt with the locks in place once the old belt is off, you can remove the cam lock, and everything will stay where it was. Now unbolt the water pump, be sure to have a bucket. Note you will need to remove the dipstick and pipe before removing the pump. Cover the hole so no water gets in to the sum!
I then put the cam lock back on (just in case). Now un bolt the tensioner, damper and roller. Also remove the thermostat housing; it’s the long ally pipe under the left hand cam, held in by two bolts.





And there it is the culprit! Not the bleeder valve (a hole with a ball in) at the very top of the stat. be sure to put the new one in with the bleeder valve at the top. No install the new stat and o ring and close it up.

Now install the new water pump and gasket. Then the new roller, tensioner and damper. Leave the pin in the damper until the belt is ready to be tensioned. Ensure the damper and tensioner are engaged properly.
Now install the new cam belt ensuring it is as tight as it can be between the cams water pump and crank. Get all the slack at the tensioner. Now pull the pin out of the damper and watch that damper push the tensioner in to the belt, taking up the slack. Give the tensioner a tweek to ensure it has fully engaged.


All we need to do now is remove the locking tools and turn the engine by hand, do this many times! Turning the engine by hand will show up any error you may have made. Once your happy with this everything can go back together.
On re assembly ensure the dipstick pipe is not touching the cam belt, as it can be easily bent. Then ensure that the plastic cam belt covers are locked in correctly; again you don’t want these brushing up against belts etc.

Putting everything back is pretty straight forward. However watch out for the coolant hoses make sure they are properly engaged on the radiator!

So there you have it. Time for a well earned beverage, in the knowledge that you have replaced every single thing, and saved a few quid too.

[mpk490p]

great write up wish someone would do one for the 1.9 TDI engine!

[a8 tech]

There is no need to remove the lock carrier,this is just adding to the job as on average the belt and pump takes 3 hours to fit as there quite easy.LOOSEN THE LOCK CARRIER AND PUT IT INTO THE SERVICE POSITION.Good effort though

[olds_kool]

There is no need to remove the lock carrier,this is just adding to the job as on average the belt and pump takes 3 hours to fit as there quite easy.LOOSEN THE LOCK CARRIER AND PUT IT INTO THE SERVICE POSITION.Good effort though

nice write up!
for the 'home' mechanic removing front is always going to be better so you can see exactly what your doing, fairly straight forward but not something you want to get wrong for the sake of 20 mins extra work

[rob s]

brilliant write up i was be using this when i change mine

[spellmaster]

There is no need to remove the lock carrier,this is just adding to the job as on average the belt and pump takes 3 hours to fit as there quite easy.LOOSEN THE LOCK CARRIER AND PUT IT INTO THE SERVICE POSITION.Good effort though

I guess, I just found it easier to sit on a pillow and work with everything right in front of me. leaning over the front pannel hirts my poor back

[onzarob]

Great write up, but please promise me you'll buy another axle stand with the money you've saved....

[2.830v]

Excellent.....this is just the kind of thing I come to forums for. I've been a member at BMW5 for a few years, however this is my return to VAG. I have this job to do with some urgency. I've just picked up a 97 2.8 30v with only 65k on the clock, neither of the previous owners thought it required the belt done , as "Audi say it needs done every 85k".............Sweet, how thick are some people, the fact its a 12 yr old bit of rubber apparently doesn't figure.

[spellmaster]

Great write up, but please promise me you'll buy another axle stand with the money you've saved....

I do but i couldn't find the bloody things! (I actually have 6! somewhere) besides with the wheels on it just 'wonked' over a bit