andyb8391

I have a 1998 ford f150 4.2 manual tran... there is an extreamly annoying noise, it sounds like maybe a heat sheild or something. my buddy has a f250 with the same noise... can anyone help me look for the problem??? thank you!!

koja7296

Do what the rest of us do, get under there a look for a problem. Sorry to be so blunt , but really, how else you going to find it?

A7X

Probably the catalytic converter heat Shields...

1999f1504x4

Mines the same. Its the heat shiels wrap something around them or rip them off whichever you prefer.

hotpursuit58

heat shields on the cats? my 04 fx4 does it when im on the throttle, i took the heat shield off around the muffler still didn't work. im not mechanically inclined so before i start taking things off, i would like to know where to start, too.

A7X

The Shields that are usually suspect are on the catalytic converters themselves... Not near em, not next to em not above or below but directly wrapped around and crimped onto them...

If you don't know what catalytic converters look like, here are some without the heat shields on em... And there are two more smaller ones in front of those as well with shields..

hotpursuit58

sweet! thanks! i bent them a little but haven't taken them off yet. i will get them both off and see what happens.

A7X

No problem! There's no harm in pulling them right off, I'm sure the heart shields are there only to keep from burning yourself as there are other aluminum shields all around them so there is no heat exchange between the cats, frame and body

aerosurfer

Check your U-Joints. I had a rattle under for over a year and couldnt diagnose it. I always assumed it was a shroud or head shield, but climbing underneath never found anything loose. Went to go Grease my slip yoke and found my rear Ujoint was shot and it was the driveshaft making the noise.

azmidget91

the heat shields are to keep the heat in the cat so they are more efficient