Contour Enthusiasts Group Archives Forums General Troubleshooting New air filter, and fuel, but hiss under bay?

Hello,

I was doing some maintenance tonight as in replacing the air filter and fuel filter.

All went well on both fronts, but after I test drove it I opened to the hood to verify just to check things I heard a hissing noise.

http://img256.echo.cx/my.php?image=rear7tz.jpg

In that picture it seems like it's coming almost right below the green vac line, and I know they break and crack, but I did not feel any air from it.

It just sounds like it's between the EVR there and the EGR port just below the UIM.

Any suggestions? I'll try to get a pic tomorrow when it's light out, and post.

Thanks for any help.

One crankcase breather tube is there (PCV valve). In addition, it could be the tubes for the DPFE sensor.

PCV seemed fine. I replaced it @ 62k and the car has 70k on it now.

It seems more logical that it would be a tube from the DPFE sensor, and I'll check that tomorrow when it is light out.

It does seem to be lower in the engine where the DPFE is, but that is just where it sounds like it is coming from. I'll check those tomorrow some time.

I did replace the air filter with a stock K&N air filter, but the noise I am hearing is definitely a hiss, and doesn't change at all really with throttle.

I dare say it almost sounds like it's coming from the LIM or something, but a hose seems more logical.

Thanks for the quick response.

Tony,

I checked the hoses, and I didn't feel a leak.

I took my time to see if I could feel anything else, and nothing was leaking or anything.

Do you think it's caused by the stock K&N air filter? Is it making a hiss while sucking in air?

Thinking of it now, I should put the paper filter back in and see if the sound changes. I'll do that later today, and report back.

Thanks again Tony.

When my Zetec is hot after shut-off, the expansion cap hisses for awhile. Open the cap a little and see if it goes away.