08-11-2013 02:33 PM
I called Lenovo Support after starting the thread and learned that they do not send out parts like fans or motherboards for warranty claims. Instead, I had to sent my computer into Lenovo for repair. It took me a couple weeks to find time to wipe the machine to remove any personal data, but I finally called support and had them send me a box to ship it back to them. The box was overnighted and arrived the next morning. I dropped it off at a local UPS store Monday morning and my computer was shipped back and delivered two days later on Wednesday afternoon. Much faster than 7 business days they quoted.
The T430 was finally unboxed today and I started setting it back up. The fan assembly was replaced and they also replaced the cracked power port. I am happy to report that the dice landed in my favor, and this fan is just as quiet as my other T430.
I am a little disappointed that I wasn't allowed to replace it myself, but I can't really complain... Sending it back to Lenovo to get repaired under warranty fixed my fan within 3 days. There is a chance this might not work for everyone since this seems to be a intermittent hardware issue, potentially from one of many suppliers of the fan, but you can probably keep sending it back to Lenovo until it comes back quiet.
I would like to mention that the little fan noise that my quiet T430's make is a little odd sounding. The first stage fan speed is the one that sounds the most odd (the sound of air rushing out at higher speeds muffle this subtle sound): With my ear 1 inch away from the exhaust of the fan on the left side of the machine, the fan sounds like it is rubbing on something, producing a noise similar to noisy brushes on a DC motor or "white noise." (it is hard to describe). But the really interesting part is when the machine has been idle and the fan kicks off, the rubbing sound suddenly drops off, as if there was a brake on the fan. My W530 and W500 produce a "normal" fan sound that gradually changes as the fan speed changes. This rubbing sound in the T430 is a little concerning and I am not 100% confident that these T430's will stay quiet over time. Luckily I have 3-year warranty on these T430's, so I won't get stuck with a loud fan should they become loud.
I hope this helps some of you out there. I am sorry I wasn't able to look for the root cause of the noise issue (didn't want to void my warranty), but Lenovo will attempt to repair a fan noise issue by replacing the fan assembly and they do it in a timely manner.