Exhaust woes 5.3


Original poster
Dec 8, 2011
Way back on the os, went thru a series of posts about a rattling converter on a Rainier. Never really got resolution & installed a plug spacer on the aft o2 sensor to eleminate the CEL. Rattle went away no power loss and decent mileage. Yesterday rattle came back with a vengence. Looks like a new y-pipe is probably going to happen. Local muffler shops really don't excite me with "we'll see what converter will fit". I may change the exhaust while I am at it & everything is loose. The muffler has some weepage on the front. 112,000 miles 5.3 engine code P 49 state

GM lists a different pn for each year of the Rainier:
2004 151942248
2005 15119821
2006 15798414
2007 15813517

Magnaflow lists 93496 (standard) & 49650 (oem) both only for 2007.

In talking with Magnaflow, they can only list a FIT if the particular vehicle has been tested by them, therefore only 2007.

The million dollar question is--- what is/are the physical differences in the exhaust by year? Flow rates of converters or ? Exhaust manifolds are the same part number for all years

Also, has anyone used the Magnaflow 16833 cat back system on a 5.3? It is listed only for the I6.


Nov 20, 2011
Any exhaust for the I6 probably wont fit either V8, you're better off getting an exhaust for an SS instead. Magnaflow makes one for the SS and it has been confirmed to fit the 5.3 as well.

Perhaps look on TBSSOwners.com and try to buy a stock y-pipe off an SS guy who has upgraded to headers. Just a thought, probably a lot cheaper and is guaranteed to work. Or buy an aftermarket y-pipe yourself (but might have to get headers too, not 100% sure on that).


Dec 12, 2011
If you lived closer I would give you the exhaust I just took off my TB. It would just need to be welded where I cut it and then you would have duals out the rear.

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