Morning rattle
Thread Starter
7th Gear
Joined: Sep 2001
Posts: 7
Likes: 0
From: Whitehouse TX
Morning rattle
I've been a lurker here for about a year and really enjoy this site.
I've got a '97 coupe that is making a rattling sound when you first start it up in the morning. The sound is similar to a piece of plastic stuck in a fan. After about 5 minutes the sound goes away and it drives fine. Could this be a bearing problem? Any ideas would be helpful. Thanks.
I've got a '97 coupe that is making a rattling sound when you first start it up in the morning. The sound is similar to a piece of plastic stuck in a fan. After about 5 minutes the sound goes away and it drives fine. Could this be a bearing problem? Any ideas would be helpful. Thanks.
Melting Slicks
Joined: Aug 2000
Posts: 2,248
Likes: 1
From: Newland US
Re: Morning rattle (SonnyParker1)
SonnyParker1,
I think the noise you're hearing may be coming from the A.I.R. pump. It only runs at start-up and the length of time it runs is dependent on engine temp. You might try shuttining off the engine when it is at normal operating temp and then restart and see if the noise is still detectable.....if not, then that would pretty much confirm the noise is from the pump....possibly a dry bearing.
The pump injects air into the exhaust system in order to burn off any of the richer start-up mixture that may be unburned in the exhaust system.
A failed or failing check valve(s) located on the exhaust manifolds, may be allowing moisture to condense within the pump.....I don't know if this is a problem on th LS1 but it was on the LT1 F-bodies. GM eventually issued a campaign which called for a pump replacement on the LT1 in my Z-28. They installed the updated A.I.R. pump and reimbursed me for the cost of a new pump that I had installed myself about 35K miles previously.
Good luck.
Mark
I think the noise you're hearing may be coming from the A.I.R. pump. It only runs at start-up and the length of time it runs is dependent on engine temp. You might try shuttining off the engine when it is at normal operating temp and then restart and see if the noise is still detectable.....if not, then that would pretty much confirm the noise is from the pump....possibly a dry bearing.
The pump injects air into the exhaust system in order to burn off any of the richer start-up mixture that may be unburned in the exhaust system.
A failed or failing check valve(s) located on the exhaust manifolds, may be allowing moisture to condense within the pump.....I don't know if this is a problem on th LS1 but it was on the LT1 F-bodies. GM eventually issued a campaign which called for a pump replacement on the LT1 in my Z-28. They installed the updated A.I.R. pump and reimbursed me for the cost of a new pump that I had installed myself about 35K miles previously.
Good luck.
Mark
