During a long journey I
became aware of a rattle from what sounded like the front of the engine. It was
only at certain revs, about 1200rpm. Later the noise seemed to disappear, only
to reappear a month later, but at a different rpm.
On the next long journey,
the engine suddenly lost power sharply during an overtake accompanied by a
whistling noise. After a few miles the power of the engine reappeared, but the
rattle was very loud. It sounded very similar to a cam rattle.
Fault was traced to a broken ceramic element in the offside Catalyst. The
noise transmitted through the exhaust manifold so that it sounded as if it was
coming from the front. The noticeable whistling noise was the sound of exhaust
gas blocked by the broken element.
Cost of repair was £360 inc labour.