Ran over chunk of ice; hissing sound while engine is on?

I ran over a chunk of ice at about 15mph. I could definitely hear it scraping the undercarriage. Now, when the engine is on (regardless of RPM), there’s a hissing sound (like air escaping, or a belt sliding against something) coming from the back right side of the undercarriage. Any idea what I damaged?

No smoke, no leaks… just the hissing sound.


Exhaust leak…such as a hole in exhaust pipe or muffler? Usually that’s not a hissing sound however…

Take it to your local quickie-lube and they will probably be able to spot the problem. Sounds like a quick fix.

Um, NO!

Do not, under any circumstances, take the vehicle to a “quickie lube.” In many, many instances that’s asking for trouble.

If you have a problem with a vehicle, take it to a MECHANIC.

The only thing I can think of in the location you mentioned is the exhaust system, but if you’re hearing unusual noises you should have someone (a mechanic, not a lube tech) put the car on a lift and inspect it.

How is your braking? Fuel mileage still the same, or worse? You may have hit one of those lines.

Perhaps you managed to smash…or smush…some ice or snow up under your car that wedged itself against the plastic covers uder the front and more importantly over your engines main pulley…if a plastic cover or snow/ice is pushing up against the plastic cover it may be now contacting the main engine pulley. The good thing is that this isnt that serious and may go away when it melts…the bad is that its ccccold where I am so it might not melt and continue to rub…if it is rubbing…and thus burn a hole thru the plastic panel that MAY be rubbing your main pulley. Just a theory… Take a look under your car and see what you can see…you may be able to spot it from under the hood…look down near your main pulley.

Braking, fuel economy (from what I can tell - this only happened today), etc. is all normal. The ONLY thing I notice is the hissing (which is really only audible from outside the car, or inside with a window/door open).

I have a friend with a lift who can put it up tomorrow and see if anything is immediately apparent. But still, I appreciate the answers. It’s nice to have some idea of what to expect.

Take it to your local quickie-lube Oh no! Please never a fast lube place, not even for directions.

Those places just make too many errors. The business model includes having very cheap labor, sell products that the customer does not need, but makes you a big profit. etc.

If you have a length of garden hose, you can use that as a stethoscope to find and identify the source of the sound.

How would a quickie-lube “technician”, who is NOT a mechanic, have the expertise to figure out what exactly is wrong?

The kids who work in these places are frequently unable to change fluids without making a serious error.
In light of that reality, I would not trust an opinion that a quickie-lube employee offered regarding a mechanical or safety issue.

Asking an employee of a quick lube place to diagnose this problem is the automotive equivalent of asking the cashier at Walgreen’s to diagnose a medical problem.

I’ve asked a mechanic and I’ve found the answer.

Apparently the sound is nothing more than the fuel pump. Either I’ve never noticed it before, or it’s gotten louder in the cold weather, or louder as the car has gotten older.

It sounds quite silly now, but I guess this is the way you learn.

Thanks for all the answers!

EDIT: If it makes a difference, it’s an '08 Sentra with 22k miles

I’ve never head a fuel pump that I would describe as making a hissing sound. Anyway, perhaps the fuel line was bent and pushed such that it is now contacting the metal body of the car in a way that is amplifying the sound?

Hissing as in air or vacume in the rear? Might mean you ruptured the plastic air suspension lines if you have that option. Easy way is to just do a little crawling underneath with a light to locate where the hissing is coming from or take it to a mechanic. Kind of hard to tell from here what it is.


It sounds almost like a leaky tire. Just a soft hiss.

I confirmed that it’s the fuel pump by putting the car in run, but not starting the engine. There’s a 1-2 second hiss (same sound) from the fuel pump. Then, once the car starts, it’s a constant noise.

As that thread points out, how often do you stand behind your car while it’s running? Maybe that’s why I assumed it was new, and assumed it was the result of the impact with the ice.

Sure fuel pumps often sound like a hiss…thats the exact word I would use. The thing is…that sound has always been there. We were trying to come up with scenarios of a new noise after an iceberg collision. Oh well glad thats all it is…

I’d say a fuel pump makes more of a ‘whizzing’ noise personally, but hey, glad you found the cause of your problem.

Air suspension on a Nissan Sentra- really?