Between shifts there is a loud rattle sound in front end almost sounds like something is loose?

DOMINIC28AB

MEMBER
1999 SATURN SL1
4 CYL
FWD
MANUAL
140,000 MILES

I have a 1999 saturn sl1 5-speed the car runs great except for when rpm's get up to about 3000 between shifts there is a loud rattle sound in front end almost sounds like something is loose. If I stay under 2500 rpm's there is no noise at all. My check engin light comes on abut every 3 days for about 4 or 5 hours and then goes off for a few days. Before light comes on it seems to idle a little rough on start up then is ok again. Thank you in advance for your help.

Wednesday, June 2nd, 2010 AT 6:37 PM

1 Reply

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

Hi,

The first things I recommend checking are the heat shields on the exhaust system as well as the catalytic converter.

Often times the heat shields will come loose or break and rattle at a specific RPM. However, that wouldn't set the check engine light. What I suspect is that the internal components in the catalytic converter are loose. If that is the case, you can hear a rattle and if they partially block the exhaust airflow, it can have a rough idle and set the check engine light.

Do this. Take a rubber mallet and tap on the exhaust to see if you can reproduce the sounds. Have a helper locate the source of the sound.

If you look below, I attached a pic of the exhaust system. I highlighted the catalytic converter and circled all the heat shields.

I hope this helps. Let me know if you have other questions.

Take care,

Joe

See pic below.

Image (Click to make bigger)