2005 TB Gas Cap
 

Recently purchased a 2005 Trailblazer from my daughter ... and have a question about the gas cap. When replacing the cap, it never seems to tighten ... just starts clicking with the slightest pressure when twisting it clockwise. Seems like all my other cars have caps that pretty much tighten up, then once it's fairly tight, it starts to click ... like a torque wrench would slip once the desired torque has been reached.

Is this normal? or do I need a new cap?

P.S. Wife came home today with the CEL lit ... P0455 code. Which takes me to another question. The owner's manual refers to a "Check Gas Cap Light" (if equipped) on the dash ... and I've seen postings referring to a DIC message about a loose gas cap. Tried removing the cap while the vehicle was running, and apparently my vehicle is not equipped with a "Check Gas Cap Light" ... anyone know whether all TB with a DIC display are capable of displaying a "loose gas cap" message?

Thanks!

Can't tell you about a possible dash light. But PO455 is saying a large leak has been detected in your evap system, primarily with the gas cap. You want to get a new cap: Trouble Code PO455

What about tightening the cap ... is it normal for it to start clicking with the slightest pressure when twisting it clockwise ... and never to feel like it's "locked down"?

No it's not normal. What it's doing would give you a loose fitting cap, a large leak, and an error code.

Thanks .... I'll order a new OEM cap!

I've read a lot of postings indicating that the GM caps routinely need to be replaced every year or two. Seems like if that's true, there's definitely been either a huge design defect or a really crappy supplier/manufacturer ... or both ... for years!

There seems to be a design flaw in the gas cap or the filler neck/tube. Just keep a spare around or add a gasket.