What's this sound in brand new 2012 Golf?

Maintenance/Repairs
1

I just bought a new 2012 Golf 2.5L (base model) last weekend and noticed a THUMP THUMP THUMP sound that I was hoping somebody could identify.

  • Only occurs in the first minute or so of driving, and only when the car starts cold (hasn’t been driven for 10+ hours)
  • Continues to occur if I entirely stop the car (haven’t tried turning engine off though…)
  • Sounds like it comes from around the rear passenger-side suspension area
  • Somewhat irregular THUMP sound. Pretty loud, especially if I get out of the car and go to the rear wheel area. It doesn’t occur at a constant rate, it’s more like: THUMP THUMP THUMPTHUMPTHUMP THUMP THUMP …

What’s going on here?

2

That’s what your warranty is for. Rather than try to solve this yourself, or believeing our internet guesses, take it back to the dealer. It’s FREE!

3

I’d still like to get opinions here first, thanks. Partly it’s curiosity. I have absolutely no idea what it could be …

4

Can you help yourself by getting on your knees to get your ears and eyes closer to the noise? Noises are usually difficult or impossible to diagnose when described verbally or via printed words.

Which side of the car is the exhaust located?

5

Yes, I got out of the car this morning and heard it very clearly but I still wasn’t sure what component it was coming from. I’ll have to check on the exhaust location, but the tail pipes are on the driver side of the car.

What components in the right rear of the car could possibly be making a loud noise when the car isn’t moving?

6

Could be the exhaust system is bumping against the body. About the only other thing back there I can think of is the fuel pump, but this doesn’t fit with the typical fuel pump noises. If it only lasted a short while it could be fuel sloshing in the gas tank, but that also doesn’t seem to fit what you describe.

7

Interesting. Is there a reason why the exhaust system would only bump during the first minute of warm up?

Just to be clear this is a loud sound. When I stood by the rear wheel it was as loud as clapping your hands hard right in front of your face.

8

In general the leak detection pump will run for a few minutes after a cold start to test the evaporative emissions system for medium and large leaks. It may be possible to notice when it is running but it shouldn’t be loud. I believe on a Golf the pump is located near the right rear wheel well.

9

If the dealer claims ‘they all do this’ pick out another 2.5l and have them start it up, see if it does.

10

I asked on a Golf forum and somebody said it was the fuel pump priming itself. I also found this: “It’s probably the Leak Detection Pump for your Evap emission system. Every time you drive, the system will pressurize your fuel system, than monitor it to see if there are any leaks. The LDP makes a low pumping sound.”

11

Thanks. Doing a search for “leak detection noise vw golf” reveals tons of threads on the subject. Sounds like it’s perfectly normal.