Engine Noise in 98 Jetta GLX

[John Kiekhaefer <jonnk@execpc.com>]

I have a 98 Jetta GLX with 16K miles on it.  Over the last few thousand
miles I  have noticed a noise developing in the engine.  It occurs after
the car has been driven a good amount and the engine is hot.  You notice
it when you stop the car and put it in neutral.  The noise is a
repetitive thumping that is moderately audible and comes and goes.  It
is audible in the passenger compartment but not outside the vehicle or
with the hood open.  It comes from the right side of the engine (not
driver side).

I had the car to the dealer for the 15K maintenance.  They told me it is
the valve associated with the fuel vapor cannister.  It is opening and
closing as needed.  They claim it is functioning properly and that the
noise is not abnormal.  However, it seems to be getting worse to me as
the miles go by.  It was definitely not there when the car was new.

Any comments would be appreciated.

John Kiekhaefer
98 Jetta GLX Red, Cloth Interior, 5 spoke GTI Wheels, Rubber Floor Mats
95 Jetta GLX Black, Leather
87 Jetta GLI 16V Red
84 Jetta Grey