Woman Starts Her Buick. Then It Makes A Noise Unlike Any She's Ever Heard: ‘Does Anybody Know What’s Going On?’

The cause of a violent startup rattle plaguing a Buick Enclave in a viral TikTok clip didn’t take long for online auto experts to diagnose. That was the lone sliver of good news, but it led to many other complicated and expensive questions for the vehicle’s owner.

Within hours of creator Stephanie (@stephanie_ann06) posting her video, mechanics in the comments jumped in to let her know the issue was serious. The explicit and underlying question behind thousands of comments became, "Is this SUV worth saving?"

“Take to Carmax after putting oil in it, and take whatever money they offer for it,” was one of the more popular comments on the clip that’s been viewed more than 1.8 million times.

Buick Enclave Rattling On Startup: A Timing Chain Problem?

At the start, Stephanie stands outside the Enclave and asks viewers to help identify a troubling sound before climbing behind the wheel and starting the SUV. A loud metallic rattle erupts for several seconds before the engine settles into a normal idle.

One commenter, who identified himself as the owner of a licensed repair shop, quickly offered a detailed diagnosis, explaining that the timing-chain tensioners were likely losing oil after the engine shut down. The result of that oil loss was the chain and cam phasers clattering when the Buick started again. The noise stopped, he explained, once the engine rebuilt enough oil pressure to operate the tensioners.

The proposed repair was a serious job, with substantial parts and labor costs. He said the Enclave could need new chains, tensioners, and cam phasers, calling it a “terribly expensive job.”

Reaching those components can involve so much labor, he added, that many shops remove the drivetrain from beneath the vehicle rather than attempt the work with the engine in place. Stephanie soon offered a detail that appeared to support the commenter’s theory: The rattle had previously gone away after oil was added to the Buick.

“Well what about the fact that when we put oil in it the other day, the noise went away for a few days, what does that mean?” she asked.

That detail appeared to support the timing-chain diagnosis, since tensioners depend on engine-oil pressure to hold the chain tight. If the Buick were low on oil, or if worn tensioners were allowing pressure to drain away while the vehicle was sitting in a parking lot, adding more oil would help them pressurize and briefly eliminate the startup rattle.

Several commenters agreed: The fresh oil may have quieted the symptom, but the underlying problem remained. One self-identified GM mechanic agreed that the Enclave likely needed new timing components and warned that replacing them would be labor-intensive.

The Repair-or-Replace Debate

If the commenters’ diagnoses are correct, the repair cost to eliminate the rattle could be considerable. Current estimates place timing-chain work on a Buick Enclave at roughly $2,500 to $4,000, depending on the SUV’s model year, local labor rates, and how many components require replacement.

Labor represents much of that expense because the timing system is buried inside the engine and requires substantial disassembly before the problem parts can even be reached.

There is also some history behind the diagnosis. General Motors previously acknowledged that certain early Enclaves equipped with its 3.6-liter V-6 could experience premature timing-chain wear under some driving conditions and with extended oil-change intervals. The company responded by recalibrating the oil-life monitor on affected 2009 models so owners would be prompted to change the oil sooner.

That history doesn’t establish for certain what is wrong with Stephanie’s Buick, but it does point her toward a likely problem to give to her mechanic. GM has instructed technicians investigating engine rattles in later 3.6-liter Enclaves to begin by checking that the oil is full and that the engine has sufficient oil pressure, which the armada of online experts wasn’t able to do.

Before deciding whether to spend thousands repairing the SUV or move on from it, Stephanie needs a shop to reproduce the noise during a cold start and determine whether it is coming from the timing system. TikTok may have produced a convincing answer quickly; the harder question of whether the Enclave is worth the potentially high cost rests entirely on Stephanie.

If the rattle is tied to low oil rather than damaged components, the immediate task will be finding out where that oil went and whether the Enclave is leaking or consuming it. If a mechanic confirms worn chains, tensioners, or cam phasers, she will have to compare a repair bill that could reach several thousand dollars. And if the inspection reveals broader engine damage, replacing the vehicle may become the more practical choice.

Motor1 reached out to Stephanie via direct message and comment on the clip and to General Motors via email. We’ll update this if they respond.