Lancevance

My 2014 Boxster has developed this squeaky/rattling noise coming from the front of the car, and it's becoming quite loud.

It appears to be coming from either the underside of the dash or the pedal box, but I'm not sure. The noise is not consistent and sometimes disappears for a few days, only to return. The noise appears while driving (regardless of whether I'm touching the gas or brake pedal), and sometimes also when stationary, and rarely even shortly after parking and turning the engine off.

I cannot figure this out and it's driving me nuts! Has anyone every encountered this before?

Please see below a link to the noise:

TMc993

A wild guess...Maybe debris in the HVAC fan? The fact that the noise sometimes continues after the engine is off could be the fan winding down. Again, just a WAG...

thecajunboy

Miniature hyenas? Man that's wild. No clue, except maybe looking into that fan idea from TMc993.

Lancevance

Thanks, I'll test with the fan off. Initially I thought it might be brake pedal related, because sometimes the noise reduces when I take my foot off the brake, but I found out it's not always the case. It's such a weird noise too.

Titanium5150

That sounds like the infamous fuel tank squeak. The pads between the fuel tank and the chassis either wear out or slip out of place.

Does this happen after you fill up the tank?

Search, you'll find plenty of info and a TSB on it.

Lancevance

Just drove with the fan off and it's still making the sound. Gas tank is about 75% full

rdboxster

I was able to reproduce the noise by wiggling the gas tank. It’s under the battery on the drivers side, just grab it and try to move back and forth. If it does squeak try some silicone spray between the tank and firewall. That resolved mine for a year until I had a chance to repair.

Lancevance

Thank you. What kind of silicone spray did you use and approximately how much? Just WD40 or something special?

BondJ

WD40 is oil based. Silicone spray is oil-free and suitable for plastics etc. Lot of choice on-line, motor factors etc. Just a few £/$

rdboxster

Agree not wd40 but silicone. Get one with the red nozzle extension. Spray the silicone along the firewall while moving the tank until the squeak ends. It’s a bit of luck if the silicone hits the right spot where the pad was. There is a good video on repairing in a thread about the tank issue. I think it’s in the 991 forum.

WhtKmanGT4

OP,
Does it sound like a styrofoam cooler squeaking?

Does it go away with a full tank of fuel?

Early 981 Caymans and Boxsters had the fuel tank strap felt liners that would slide to the side. The tank then chaffs and squeaks against the cowl. Once fuel level goes down you get a very similar noise. This sounds a lot like what you have going in. There were TSBs out on the condition and repair. I had it on a 2014 CS.