I see a lot of videos online where the individuals claim that you have to remove the intake plenum on a 1st generation Chevy Traverse (or any other 1st generation Lambda platform such as the Saturn Outlook, GMC Acadia, Buick Enclave) to service the rear bank spark plugs. That option usually entails loosening or removing many of the smog/vacuum lines and wiring harness clips, and moving these items to one side to gain the necessary space for plenum removal.
Long story short, you don't need to do any of that. I just replaced the plugs in Mrs. Goodfellow's 2012 Traverse LT in under 40 minutes while moving at a leisurely pace. Guys my age can only move in a leisurely pace; there is no fast mode anymore.
There is enough room between the cowl and the intake plenum to gain access to the fuel injector connectors, the coils, and the plugs; with room to spare.
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The most useful tip I can give is to douse the coil connectors with a few squirts of WD40 and wait a minute or two. The connectors will slide off much easier than when they are dry and full of dust and dirt.
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The tools are basic. For the rear plugs I used a 3/8" swivel plug socket and 6" extension, and a 1/4" deep 10mm socket and 3" extension for the coil hold down bolts. I opted for locking extensions since I'm clumsy and often drop the socket down the back of the engine while fumbling around.
To make things even easier on my tired old hands, I used a set of 3/8 and 1/4" thumb drives to extract and install the plugs because it took too long to do the job with the limited swing of a conventional ratchet in that tight space under the cowl. That said, it's only a small luxury, the job can be done with a regular set of ratchets.
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The access is pretty good, and the rear plugs and coils are easily identified and reached.
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Plugs looked pretty damn good for 104,000 miles. Ground electrodes were a bit worn, but not excessively. Could have gone another 25K easy, but GM recommends plugs at 100K, so I replaced them with OEM AC/Delco Iridium.
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I was worried that the coils would be a PITA to get out, but they lifted out like a breeze. Probably due to the dielectric that was used to install them originally. I opted to reuse these coils and replaced the dielectric grease both on the collar and the coil boot end.
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The rears took half an hour, while the front plugs were straightforward and took less than 10 minutes. Quite an easy job for the DIY guy; no stress or strain involved.
The only other necessary step for the front plugs is to unhook and unplug the purge valve connections and remove the 10mm bolt holding the purge valve in place. Removal of the purge valve is necessary to gain access to the number 6 cylinder coil which sits directly underneath the purge valve.
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Hope it helps some of you guys that have the 1st Gen Lambda platform vehicles. BTW -- looking at the 2nd Gen plenum, I think it's a safe bet that you can do the same procedure on those vehicles as well.