1998 Suburban Whining noise

I just bought a 1998 Suburban and when you turn the key before it starts I hear a whining noise back by the gas tank ( I assume it is pumping gas because I have heard this noise on other vehicles).
The problem is that once the vehicle is started the noise is constant.
Does anyone know what it is. Also what should the gas mileage be in the city and highway.
I think it has a 40 gallon tank. Is this true.

Thanks for any help

Is the noise really, really loud... like a blender? If so, then the fuel pump may be going bad :(

you might just need to change your filter on the fuel pump (not as easy as it seems), and i think the 98's are a 42 gallon tank. :bloated:

A humming noise from the gas tank would be the fuel pump. Changing the filter could help it out but might not totally correct it! I would not do anything with it after a fuel filter change unless it bothers you since a new pump is in the 400 dollar price range. To prove it is a fuel pump turn the key on listen to the hum if it stops after 2 seconds that is the pump.

dont wory its normal-- nothing to wory about--

the fact that you can hear it is good and telling you it works---
if it was going bad you wouldnt be able to hear it if your woried about it take it to any good mechanic

KAYLIEBUG, These fuel pumps are notoriously LOUD and borderline obnoxtious. The tank shoud be a 42 gallon is you have a 2 wheel drive 1500. I've owned 2 suburbans and 1 yukon. The suburban I have now is undoubtedly the loudest fuel pump of the 3. I've been driving it for the past 15k miles this way...it had 50k when I bought it.... so basiclly stop by any chevy dealership, let a service advisor listen to it and they can tell you if there is anything to be conserned about. Good luck!!
- Mike

Yep as they all said fuel pump, fuel filter change out is not that hard and cost about 9-13 dollars. On drivers side lay on your back slide under driver door look in frame rail. (remember when disconnecting lines they still have pressure fuel WILL SPRAY). As for the pump other then the pain of dropping the tank you can change it out in about 5 minutes after tank is out. At a cost from any auto parts store for pump only 35-40 dollars. Everyone looks for a whole system at a high cost, just change the pump if you need to, I just did it two times in the afternoon (and yea it still was a pain with fuel in the tank. So live with the noise. As for mileage mine gets 12-15 in town and 15-18 on highway. But you don't buy a burban if you want fuel mileage LOL.
Later