2003 Dodge Caravan

TEACHER_IN_TEXAS

MEMBER
2003 DODGE CARAVAN
6 CYL
2WD
AUTOMATIC
95,000 MILES

The engine light came on. Took it to get codes and came up as oxygen sensor and small leak in evap system. Replaced oxygen sensor, but light stayed on. The repair place told us the leak in the evap was small and they could not tell us where it was. Also, van is making a humming/whistling noise that sounds like someone blowing across the top of an empty bottle. It is LOUD! We also are sometimes having problems filling it up with gas. Something is causing the pump to sense that the tank is full when it is not. It clicks off after putting just a little gas in. The filling up problem seems to be worse when it is cold and the "humming" sound seems to be worse when it is really hot (the outside temperature. Not the van.) HELP!

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

I think I may know what the noise is coming from and where the small leak is. For fuel to enter the fuel tank, air has to be able to escape. If you craw under the vehicle where the fuel filler tube is located, you will see a smaller hose that runs along side of the filler tube. That is the breather. If it is plugged or damaged, air can't escape. As a result, the fuel backs up in the filler tube and shuts the fuel pump off. It's a pain. If there is a humming noise, that could be coming from a leak from the breather when pressure us produced in the fuel tank.

Check that and let me know what you find. As far as finding a small leak, by eye, you could look for weeks. There is, however, an easy way to find it. You need to have the system fogged. Fog is actually pumped into the EVAP system at a very low pressure (I think 1psi). The fog will come out where the leak is located. That is my recommendation if the breather is good. Also, I'm surprised your mechanic didn't recommend that.

One last thing. I understand the engine light is on again. Is it only for the EVAP leak or is the O2 sensor code still showing?

Let me know.

Joe