question about Serpentine belt on Audi A6

[Kent McLean]

Carolyn Pesta wrote:
> I have a 1995 Audi A6 and recently had the dealer change the serpentine 
> belt (74k on the car).  Is there also a timing belt in Audi’s or is this 
> the same thing?  I could’ve sworn the dealer service guy told me that 
> the serpentine belt was the equivalent of most car’s timing belt.

Hello, Caroyn.  I hope you don't mind, but I'm CCing the list,
for the archives.

The serpentine belt is also called the accessory belt; it drives
the alternator, air conditioning compressor, and power steering
pump.  The serpentine belt has ribs that along the length of the
belt. If it breaks, you need to replace it and then you can be
on your way.

The timing belt is different.  It is turned by the crankshaft,
and thereby turns the cam shafts that actuate the intake and
exhaust valves.  It also drives the water pump.  The timing
belt has teeth, with the gaps running across the short width
of the belt, that fit into indents on the crankshaft and cam
shafts.  If the timing belt breaks, either through mileage,
old age, or a frozen water pump, and the engine is running,
the pistons can and will hit the open valves, causing expensive
damage.  You will need to have the head rebuilt $$$, you will
hope there is no other damage, and then you can replace the
timing belt and be on your way.

So, the two belts are different.  The serpentine belt costs about
$50 and another $50 or so in labor to replace it.  The timing belt
also costs about $50, but the labor is 2-3 hours, so you're talking
at least $250-300. And while you are relacing the timing belt, you
might want to replace the water pump (~$100), idler pulley, and some
seals.  Done right, it's about a $350-450 job. That's if you catch
it before it breaks.

As for the mechanic, find one who a) knows what they are talking
about or b) can explain it to you better.

Cheers,

Kent McLean
'94 100 S Avant, "Moody"
'89 200 TQ, "Bad Puppy" up in smoke