2001 Outback Ltd engine noise

[Crabby Gator]

We just became owners of a 2001 outback ltd with a 2.5L 4cyl engine and
automatic transmission.
The car has somewhat high milage at 75000.
My wife is concerned about some engine noise that is audible from inside the
car, even when the engine is warmed up.
At first I chalked this up to the piston-slap problem, but she keeps on
hammering me with this issue, making me more paranoid.

Could there be some other cause of the noise in the engine, like maybe valve
lash or something? It kinda sounds like it could be valve lash to me but I
don't know enough about these engines to make a guess. It's kind of a tapping
sound, and it does vary with RPM.
However the noise is fairly slight and certainly can't be heard with the
radio turned on. It's most noticeable at low RPMs, like when taking off at a
green light.

 

[Kurt C. Hack]

Not to preclude you from taking this to a reputable Subaru dealer to
have it checked out, but here what it could "possibly" be.

My 2002 OB was noiser and the engine harsher than other new cars, even
when brand new. At first I thought that this was a defect, but after
testing other Subaru's I found that it was perfectly normal for this
vehicle for a couple of reasons.

1. The fuel injection system on Subaru's seems to be rather noisy,
especially when cold. You can hear the injectors opening and closing
which will increase in speed comensurate with engine speed.

2. The infamous piston slap does represent itself, but usually just when
the engine is cold.

3. The 2.5l engine is a bit harsher than most other 4cyl engines, and
can seem louder. This is due to the boxer style of the engine, and the
fact that this a pretty big bore 4 cyl engine.

Hope all works out well for you!

-Kurt

 

[Roy Shroyer]

My 02 OBW ltd had a similar problem. Subaru ended up relacing the timing
chain tensioner.

As it was explained by to me by the tech:
The tensioner is oil filled. The origninal either had a leak or didn't have
enough oil in it (had air in it).
When the engine was cold the tensioner left the chain loose until the air
pressure built up enough to tighten the chain.

I had that repaired at 7k miles and its been trouble free since (47k miles).

This noise was so loud that I thought the engine sounded like it had a rod
knocking. My wife called it the "cement mixer".

This may give your tech somewhere to start looking.

Roy

 

[Crabby Gator]

Thanks for the advice! Since I _am_ my tech, I will look in to that
straight away.

CbG