engine idle noise...

[secreTTasianman]

I've noticed recently that when my car is idling I hear a random clicking or ticking or various inconsistent tapping sounds from the car, I don't know for certain it's coming from the engine.......anyone encountered a similar experience. Is this serious? Sorry for the vague and general descrip. TIA.

What year is your car?
Mileage?
Model?

Are you running Mobil 1 0W40? How is your oil level?

Are you sure this is not the cats cooling off or heating up?

[denverpete]

Originally Posted by secreTTasianman

I've noticed recently that when my car is idling I hear a random clicking or ticking or various inconsistent tapping sounds from the car, I don't know for certain it's coming from the engine.......anyone encountered a similar experience. Is this serious? Sorry for the vague and general descrip. TIA.

Sounds like your Cats and Exhaust heating and cooling.

[secreTTasianman]

1999 boxster
52k
M1 0w40 every 3-5k

I haven't noticed any performance depreciation. You must be right about the cats. Thanks for the replies.

[RandallNeighbour]

My neighbor had a cat crawl up into his car to keep warm one night and wow, it made a real racket when he was warming up the car the next day... but only for a little while and then it was all quiet and no more cat noises whatsoever. :dance:

[carguy]

Sorry to revive an old thread, but I have exactly the same issue on my 2001 986 S. It happens only at idle, and is an intermittent (ie. once every 1-3 seconds) clinking or tinking, metallic sound like flicking a thin piece of metal with your fingernail. This occurs well after the car is warmed up, and did not used to happen, so it is not normal metal expanding.

Any ideas?

[Chrisp]

I had a similar noise on mine -did a big search on here and it could be one of three things:

1. Damaged CAT honeycomb - tap the cats with a rubber mallet when the car isn't running to see if they rattle.

2. Loose heat shield - give them a wobble to see if they've worked free.

Or..

3. (which I found myself) The sensors screwed into the top of the CATs can unscrew themselves, and will rattle like you describe - both my CATs did it one after the other (one twice). Reach up and check them (not when the car's warm though).

Hope this helps!

[RandallNeighbour]

Originally Posted by Chrisp

2. Loose heat shield - give them a wobble to see if they've worked free.

Note that there are two kinds of heat shields around that area. The first is the shiny aluminum stuff that is easy to bend and can easily cut you if you graze it just right. If the edge of some of this stuff is touching part of your exhaust, it may buzz or make noise.

The other heat shield is steel, which loosens with age and heat expansion/shrinking. It's found ahead and behind your cats. I had a vexing, tinny rattle at certain low rpm's that turned out to be one of these heat shields. I put the back of the car on ramps, started the engine, asked the wife to rev it a bit, slid under the car, found it, and whacked it real good with a hammer a few times to bend it and make it fit tightly against the piping after the cat. Problem solved.

And whacking the crap out it with a hammer after six months of listening to it was very satisfying indeed

[pbanders]

In general, I've found that any engine noise I really need to worry about makes itself known to me quickly and loudly. Make sure your oil level is correct and belts tensioned properly. Beyond that, any minor taps and clicks are best ignored, it's easy to get obsessed about them.

[carguy]

Thanks for info guys...I'm taking it to my mechanic tomorrow am to let him have a look/listen. I am wondering if it's maybe something to do with the clutch mechanism..just a gut feel. It seems my clutch is rather grabby lately, and I also notice that I hear the same type of rattling type of noise at a certain point as I engage it.

[carguy]

Just to update the thread, my mechanic found out it was the alternator! So getting that replaced with a Bosch refurbished one. As usual, not cheap, $700 for the whole job including the part.

[Brucelee]

Originally Posted by carguy

Just to update the thread, my mechanic found out it was the alternator! So getting that replaced with a Bosch refurbished one. As usual, not cheap, $700 for the whole job including the part.

Man that is a lot of money for a rebuilt unit.

Glad you found out what the issue was.

[carguy]

He had to spend some time figuring out what exactly the problem was, so for that, and the part, and installing the new part, I am ok with it.