2004 Subaru sounds like 1960s beetle

The engine on my 2004 Subaru Impreza has been periodically sounding funny. The best way to describe it is the car sounds like a 1960s beetle only with a much deeper sound and more metallic. That is the best way I can describe it. It only happens when the engine is cold and stops as soon as the car has been running for 10 or 15 minutes. In the winter the sound comes every time I turn on the car especially if it is below freezing. During the summer or warmer days the sound is gone and my engine sounds normal. I have lived with this sound for a few years now thinking that it is simply a cold engine. But something tells me maybe I should check this out.

Why does my car sound like this during cold temperatures? Is it something serious? I would greatly appreciate any advice.


My guess is there is a leak in the exhaust system that at least partly closes up as the parts involved get warm and expand.

Any good exhaust shop should be able to figure it out quickly. It may be little more than tightening or replacing a clamp, or it may require replacement of a part of the exhaust.

If this is an erratic, non-steady, rattling type of sound then I might suspect a wrist pin rattle or piston skirt rattle. More likely the latter.

If so, it won’t hurt anything.
That’s a barely educated guess since your description is a bit fuzzy to me.

My original thought was “exhaust leak,” but after reading the post again I have to wonder; could this be the infamous Subaru piston slap?

I believe Subaru piston slap was corrected in 2000 or prior.

What weight motor oil do you use in the cold temps. My WRX motor is a bit knocky at 10F and below although I use 10w30 which is suggested for >0F.

Piston slap is still quite common in Subaru 2.5L engines, well after 2000.

Piston slap can occur on any vehicle; either by design or by a contributing factor such as overheating or low oil.

Contact Intermountain Repair in Longmont-303-651-9525

my 2003 outback wagon with the 2.5l 4 cylinder engine has developed this loud ticking at about 58k, coincidently after major warranteed engine work was performed at the dealer… head gasket oil leak which subuaru issued notices about and the timing belt, which had to be removed in this service, by the way, no labor charge, only for the belt itself.
funny, i’ve also described this sounding like my college 1962 beetle…
this car is going to the dealer next week for diagnosis and repair… this is a most annoying development for a 25,000 dollar car…

I have a 2004 Impreza (TS Wagon) and this is exactly what my car sounds like on cold mornings. I developed this around 50K miles (although I might have faintly picked it up earlier in extreme cold conditions).

I recently had my 60K major service performed and the mechanic stated that he didn’t hear anything unusual w/ my car, even after starting it on a cold morning (and everything checked out fine). I didn’t know then about this “piston slap” problem so he could have just heard this and not thought it odd because he is a subaru mechanic who hears this all the time. I live in an area w/ a lot of subarus and I’ve also heard this on other fellow owners’ cars sitting idle at stop lights.

I’ve done some reading on the web, and there are reports and claims that “piston slap” still exists for 2004+ subarus, but my question is (1) does this at all reduce the life-expectancy of the engine (I’ve seen differing reports on this), (2) will subaru warranty this and (3) is this something that could be resolved (or lessened at least) by changing motor oil (again, I’ve seen some claims about this on the web)?

Your description sounds exactly like piston slap common on chrysler K cars with the 2.2 or 2.5L engine. The fix for this is to turn up the radio.