I have an F150. Love the truck. It has the 5.0 V8 engine. The same engine shared with the Mustang and other Ford V8 platforms. It’s got plenty of power for my needs and has been reliable for the seven years I’ve owned it. And it has developed a strange rattle. I’m going to show you the likely source of the rattle and a super easy way to fix it.
The Symptom
Over the past couple of weeks, I can hear a rattle in the truck when the RPMs are low and the truck moving slowly. The rattle is intermittent. The best time to hear it is during the initial acceleration from a complete stop. Slow acceleration. Sometimes, I hear it while moving. This happens when the vehicle is moving just fast enough to shift into the next higher gear.
It is a metallic rattle that appears to happen when the vehicle hits a certain harmonic. If I get on the accelerator a little harder, the rattle is heard for a split second or not at all.
Check out my YouTube video to watch this fix. You can also hear a sample of the noise. It may not sound exactly the same, but it’s a starting point.
Sometimes the strange noise is heard while decelerating.
Others have said that the weird rattle gets much worse when they are under the increased load of towing.
A Note On Safety
Before you go under your vehicle, make sure you take all appropriate safety precautions. Emergency brake on. Wheels chocked. Jack placed in proper position. Jack stands under the correct points.
PLEASE, NEVER GET UNDER A VEHICLE SUPPORTED ONLY BY A JACK! NEVER, EVER GET UNDER A VEHICLE SUPPORTED ONLY BY A JACK! NEVER, EVER, EVER GET UNDER A VEHICLE SUPPORTED ONLY BY A JACK! As you can see, I have strong feelings about this.
In the case of my F150, I do not need to lift the vehicle. I can fit under it to do an inspection. I still engage the emergency brake and chock the wheels.
The Examination and Diagnosis
You want to slide under the vehicle behind the front wheel under the driver’s door. You don’t need to go too far. While looking up, try to determine which pipe is the exhaust pipe from the engine. It will travel in a downward direction until it reaches the chassis and then turn horizontal and run toward drive’s door before turning to the back of the vehicle.
On part running toward the door, you should see a bulging attachment. Continue following the pipe and you will see another piece that travels long the top of the pipe for a short distance. It looks like a cover on top of the pipe and wraps around about 1/3 of the pipe. This is a heat shield, and it is the section you are looking for.
The heat shield is welded to the exhaust pipe on one side. The other side is held on by a metal strap. It is the strap we are concerned with. Do not remove the heat shield to get rid of the rattle. That heat shield plays a vital role in protecting other components on your vehicle and needs to remain in place.
If the strap is loose, wiggle it to see how loose. It may pop right off in your hand. It may already be completely gone. The strap on my F150 was still there but it had a clean, straight break. It was loose and remained on the pipe only because the break didn’t open wide enough for it to fall off. A quick pull, and it was removed from the pipe.
I was now able to use the tip of my finger to test how loose the heat shield was and get it to make a little noise.
The FIX!
Going through stuff in the Project Cave, I had an unused stainless steel hose clamp. I took the clamp and opened it completely. Then, I placed it over the heat shield and around the exhaust pipe. Once in place, I tightened it down until it was nice and snug. I used a cordless driver to do most of the tightening and did the final few turns with a screwdriver. I made it tight enough that the heat shield was secure and no longer made the same noise when I flicked it.
The Result
The intermittent noise is gone. Whether accelerating slow or fast, the truck just sounds good.
This is a fix that works on all sorts of cars and trucks. In fact, it is the third time I’ve encountered this problem. The first time was on an old Honda Civic. Fixed that with a similar solution. Used a U bolt clamp that time.
The second time was on an old girlfriend’s Acura. Acura/Honda equals pretty much the exact same sound. She was complaining about the noise and when I told her what it was, she was convinced I had no idea what I was talking about. She told the mechanic that I said “the heat shield over the catalytic was busted” but she didn’t believe it. He told her I was right. That apology was sweet.
So anyway, if you have a noise like this, give that pipe a check. If that is the problem, the fix is the cost of a hose clamp.
