SchnauzerDad a écrit :
WELL GANG! THEY HEARD IT!!!
I spoke to the service writer and he told me the Subaru regional rep
actually heard the car make a cold start racket, and they are putting in a
new timing belt tensioner tomorrow. Lets see if it works.
I've been reading a lot of stuff off the Subaru
technical website and came across the following,
out of the Subaru Service / Technical
Support Line Newsletter TechTIPS JAN/FEB 2003
-- begin quote :
SUBJECT: ENGINE NOISE WHEN COLD
(Note: This is a re-release of past articles.)
We wanted to review some of the past information on
engine noise.
The 2000MY and current models, with the 2.2 and 2.5
engines were made more fuel efficient, more powerful,
and had a flatter, more usable torque curve than in
previous years. To achieve these objectives, it was
necessary to make improvements and modifications to
the Subaru engine lineup. The following are some
of those improvements:
1. Mechanical valve lash adjusters (reduces friction)
2. Lightweight pistons (reduces inertia)
3. Short skirt, Molybdenum coated pistons (reduces friction)
4. Increased compression ratio (improved power output)
5. Improved cylinder head design (improved cooling)
6. Improved induction system (improved breathing)
As a result of these enhancements, some engines may
exhibit some engine noise during the warm-up period
after a cold start-up. This noise is a consequence of
the engine improvements and is not, in any way, an
indication of any engine problem.
A light engine knock, after cold start, that gradually
dissipates as the engine warms up and is virtually
undetectable (from inside the vehicle) once the engine
has reached operating temperature, is a normal
characteristic of these engines. Repair attempts to
reduce this type noise are generally unsuccessful.
If you have a vehicle in which an engine noise is
other than that as described above, be sure to take
the time to check all possible causes prior to
condemning the internal components of the engine.
Before replacing parts in an attempt to eliminate
engine noise, the engine should be inspected externally
and internally for another source of noise. A look
at the engine oil is a good place to start. New
engines will have a small amount of metal particles
in them, but after that should be relatively free of
metal.
Another area to look at would be the timing belt
tensioner and the belt and sprockets. There have
been cases where noises coming from under the belt
covers and from external components sound like a
deep internal knock.
If a customer complains of a cold engine knock,
and the cause is from the improvements listed
above, please reassure him/her that no permanent
engine damage will occur. If the noise persists
and is still clearly audible when the engine is
warm, please consult your DSOM.
-- end quote.