Rattling Noise Jeep Grand Cherokee 04 : Possible Exhaust System? (fuel, engine, replacement)

[ShakyJ]

i6 04 Jeep Grand Cherokee. 125k

Basically you can hear some minor metal sound. A metal ding. Louder at first on cold start morning, but once warm it is a light dinging rhythmic to the engine. I have been told this may be the exhaust. With zero knowledge of an exhaust system I am not sure if this is something that needs to be replaced or if there is simply a bolt that needs to be tightened.

Thoughts?
Jason

[Hemlock140]

We had a Cherokee that rattled but it was more of a dull sound, that turned out to be broken up ceramic material in the catalytic convertor, about a $400
replacement. You can get a ticking sound from an exhaust leak at the exhaust manifold, from a loose connection or bad gasket. The sound you described could be a lot of things including a more serious internal engine problem, but a good mechanic should have a pretty good idea from listening to it.

[snofarmer]

sure, at that age I bet the exhaust system or the heat shields have rusted or come loose.
Take it to a muffler shop and have then inspect it.

[texdav]

tke it to a muffler shop and they can lift it and tell you. get a estmate if they find it is the probelm.Once did this and he found front disbarke shield was bent and cause rattle;fixed that. zero charge as it was simple.

[Drover]

Could be loose exhaust, could be a loose heat shield, who knows. Probably nothing major, but unless you isolate it yourself you won't know before having it looked at.

[11thHour]

Originally Posted by Hemlock140

We had a Cherokee that rattled but it was more of a dull sound, that turned out to be broken up ceramic material in the catalytic convertor, about a $400
replacement. You can get a ticking sound from an exhaust leak at the exhaust manifold, from a loose connection or bad gasket. The sound you described could be a lot of things including a more serious internal engine problem, but a good mechanic should have a pretty good idea from listening to it.

Wow good catch. I realize this topic is on Cherokees, but on a related note, one of my friends had a nissan sentra that had the ceramic material inside the catalytic converter deteriorate then get ingested inside of the engine. The catalytic converter was located too close to the engine. Only indication he had was a slight rattling sound at certain rpms. He soon noticed he was going through oil quickly also, but there was no oil leak detectable, and no smoke from the exhaust, but he was having to add 1 qt per week toward the end. Took it to a local mechanic and they were stumped. Took it to the dealer, they said it was probably his cc gone bad. Checked it and yep, it was bad. Then scoped his engine, and it was trashed. His cc was out of warranty, so nissan told him to take a flying leap. Apparently there was a recall issued for the altima for this issue, but not on his sentra so he was sol.

Edit: From wikipedia, referencing this exact issue:

Initially, for 2002 and 2003, the SE-R Spec V (along with the SE-R) was given an aggressive front fascia (styled after the Skyline GT-R) with side still extensions and rear trunk-mounted spoiler. Other notable features include a catalytic converter on the exhaust manifold, and air fuel ratios in a range, when driven aggressively, that could overheat and damage the ceramic catalyst substrate. This slight design oversight, along with a variable intake cam timing system that also functioned at light load cruising as an exhaust gas recirculation system (EGR), would allow the motor to ingest damaged ceramic catalyst substrate. The abrasive nature of ceramic in the cylinders was responsible for abnormally high oil consumption rates and a large number of engine failures secondary to low oil levels due to compromised piston ring sealing.