'03 Impreza annoying rattle when cold

I have an '03 Impreza TS wagon (non-turbo) and lately I'be been having an annoying rattle at around 2000RPM after starting the car when cold (below freezing). The rattle goes away after about 10-15 minutes. Any ideas what this might be?

TIA

Reply to
Fuzzy Logic
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Not piston slap, I assume? I take it you can tell the difference, since that usually goes away much quicker than 15 minutes.

I am not familiar with an 03 impreza, but my daughter's 93 impreza does this as well and suspect Subaru hasn't fixed this problem yet (my old GL did it as well :)

Check the heat shields mounted over the exaust -- they are notorious for making rattling noises. I put a large hose clamp over it to stop it, but on this group I've seen people jamb rocks between the muffler and the heat shield.

Remco

Reply to
Remco

"Remco" wrote in news:1111004858.070521.218960 @l41g2000cwc.googlegroups.com:

I suspected some kind of heat shield. The sound appears to come from the engine compartment and is definitely a rattle and not piston slap. It's intermittent and sometimes very loud. Hard to check by myself as it only happens around 2000RPM and when the vehicle is cold and lasts 10-15 minutes and then totally disappears.

Reply to
Fuzzy Logic

Try tapping the various heatshields with engine off, and cool. You got em on uppipe, downpipe, a few places along exhaust, and on headers...you'll have to pull your undercover off to check them; they are probably the #1 culprit...seen a few posts here and NASIOC on that.

Check shields for looseness, tap/whack with something like a screwdriver handle, and you should be able to find the one that makes "that noise". Some of the fasteners may be loose or rusted away...fixes might be new bolts, a hose clamp around the whole affair, bailing wire, etc...one fella put some self-tapping sheet metal screws thru manifold shield, to brace it against the manifold..whatever will work!

Reply to
CompUser

Yeah, that's a good way, definitely.

On my daughters, the heatshielf that you see right when you are looking from under the front into the engine compartment was the culprit. This particular one is two pieces, so I put a hoseclamp around it and it went away.

Remco

Reply to
Remco

In previous recent years of 2.5 II production, there was a TSB regarding the timing belt tensioner (when cold) making a noise that mimicked piston slap. I don't know if that's still an issue or not, but you might want to research that avenue. -Danny

Reply to
Danny Russell

I have the same vehicle and haven't had this happen, but it's only been well below freezing a few days here.

Reply to
Clint Patterson

I don't think it is so much temperature that causes this rattle. Ours started doing it a couple of years ago in spring -- something just likes to resonate and when things get loose, it gets worse.

Reply to
Remco

I bought a '02 TS wagon in Nov/04. There is a tapping noise upon gentle acceleration after a cold start below freezing temperatures. I overheard someone talking about such a problem being caused by the timing belt tensioner, and that it was posted in some websites. I cannot find much on the internet, and will appreciate any help in understanding the problem, the potential consequences and the fix. I did take the car to a dealer's service shop and had it parked overnight there, but they did not notice anything unusual. I probably will have to wait until next winter for some really cold weather to get the dealer's shop to check it again.

Reply to
KaiC

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