VW Passat, Mystery Popping Noise

A strange noise, something between a knock and a pop, seems to emminate from under my car, sounds like it’s coming from directly below my passenger seat area. Mechanic said it was tire rods and changed them (“the sound is gone”), but it’s still there. Only driving at somewhat low speeds, but inconsistent times, not always over bumps, sometimes when I accelerate and then take all pressure away from the gas pedal. Mechanic has offered to refund the money, but that doesn’t really address the problem as I face a 10-hour drive back and forth to Western PA next week… any clues?

What year is your Passat, and which engine does it have? All Passats are not the same.

“Tire rods?” There’s no such thing. “Tie rods?” Yes, that’s a possibility, but it’s unlikely new tie rods would have any impact on a noise that comes from under your passenger seat.

I’m wondering about the motor mounts, but since you failed to give us important information it’s hard to say.

And until you tell us how old this car is we can’t say anything about the possibilities of a 10-hour drive.

I agree with mcparadise.

Your tie rods might make noise, but this noise would not be emanating from underneath the driver’s seat. This could be something as simple as a disconnected exhaust system hanger. Or it could be something more serious, like a motor or transmission mount.

Since your mechanic seems to have no clue, why not ask for the refund that he offered, and then take it to a different mechanic? Just be sure that you DON’T take the car to Midas, Meineke, Monro, Sears, or any other chain operation.

Since the mechanic replaced tie rods for a noise that sounded like it was under the passenger seat, I’m guessing the noise is farther foreward than what you are thinking. From what you are describeing, (except for sounding like the under the seat description) and the irregularity with which it happens, this sounds 100% like a constant velocity joint is knocking, maybe both of them on the right axel alternately
They do this when they are not lubed regularily. The grease gets dry and doesn’t allow the balls to slide in the grooves smoothly or quietly and they will pop or clunk or knock.
Call a few places and see if they are familiar with lubeing c v joints with a “grease needle” or “tube”. This eliminates a lot of labor charge because they grease them through the end of the boot instead of removeing them (10 minutes, as opposed to an hour or more to R&I and grease them) If this is it then you need to have them lubed soon because replaceing them is soon to follow due to failure, especially because of the miles you will be driveing. Get them greased BEFORE your 10 hour drive!

Don’t just lube the 2 on the right side. Do all 4. They are very EXPENSIVE to REPLACE, and that time is close at hand if they are makeing this noise.