ScottB

Lately I have been experiencing a metallic rattling sound when I start-up the car after it has been sitting (e.g. first thing in the morning, after work, etc). It is quick and I cannot reproduce it if I just shut the car off and turn it back on again. I cannot say how long it has to sit before this happens, but it is certainly longer than a trip into the store. I cannot tell if it is exhaust, oil pan, or something else? I also don't know why it would only happen when the car has been off a while. Any thoughts?

Hickey322

I get the same noise sometimes. It usually only happens after sitting for a couple of days. I have no clue what it is either, hopefully someone has the answer.

RazorV3

its probably just the timing chain, mine makes noise sometimes too. i work at a honda dealer and drive s2000's (new,used, service) all the time, and they all do this sometimes and sometimes they don't.

i've noticed that it is more audible when the weather is colder...

Billman250

do a test; disable the injectors and crank the engine for about 5-7 seconds. This will bring up the oil psi before starting. Re-enable the injectors and start the engine. If the noise disappears, it can be at least narrowed down to internal engine noise.

3ngin33r1

Where is the sound located? front or rear of the vehicle?

ScottB

It sounds more like it is coming from the front of the car, however, the noise doesn't last very long. Also, since the engine is starting up, it can be difficult in the short amount of time to find the rattle over the engine.

Where I am living, cold is not a known quantity....

I'll try to pay closer attention next time to see if I can pinpoint it better.

3ngin33r1

Couldn't be a rattle in the air pump could it?

Austblue

I thought that cat convertors could rattle a little when they were warming up. It would explain why its only with cold starts. Maybe this should be moved to UTH for a better response?

Smokee

I don't have enough s2k experience but have had two Jeeps with similar rattles and it was indeed the catalytic converter. Same thing at cold start. Rattles are very hard to pin-point where they originate.

John MI blk/blk '01

Mine had it too...faint rattle for about 10-30 second at start up. It was diagnosed as piston slap. When the car would cool off for a while the sound would come back. Sounds bad but is quite common and should not cause any problems.

Sold the car for other reasons but this was not one of them.