I am looking for suggestions for a possible cause of a noise on my F150. The truck is a '95 Supercab F150, 2WD, 5.0L, 5 speed, 130K miles, original exhaust and clutch. The noise seems to be coming from the passenger side, by the passenger's foot area and kind of sounds like an exhaust leak. The speed of the noise follows the engine RPM. The part that has me confused is that it only happens under acceleration. While cruising at a steady speed its gone. Also by just reving the engine I can't create the noise. Lastly if while accelerating I depress the clutch the noise goes away when the load is taken off of the engine.

Any suggestions are appreciated.

Mark

 

When the engine is cold, check for a cracked exhaust manifold. I had one that was only loud when cold. If it is cracked, it should be easier to see when cold. Also check where the exhaust joins the manifold and around the manifold to see if any leaks there. Other posibilities may be a rust hole in the pips.

 

My brother had a suggestion. He said that it could possible be what he calls a throw-off bearing. It is located on the tranny shaft where the clutch and everything is. If that is the problem and it goes out completely, you wont be able to shift the truck in to 1st (or any other gear for that matter). Another possibility is that the donut gasket could be blown where the exhaust pipe connects to the exhaust manifold.

 

Thanks for the suggestions. I have had couple of people ride in the truck they both think it ths donut gasket or a least something exhaust related.

Now the question is do I live with the noise or do I risk breaking the studs to try replacing the donut gasket. Anyone have luck replacing the donut gasket without breaking the studs.

Thanks

 

You can risk breaking them. I like the hot wrench technique. Spray them with some wd-40 every day for a couple of days. Then get the torch and heat the suckers up red hot. crank away. repeat if neccessary. [usually is] It has worked for me in the past. Keep a garden hose or fire extinguisher handy.

I know at the exhaust shop. They use an oxy-acet. torch and just remove it completely and then through bolt it. [at least where I went]

Muffler shop charged me $50.00 to have it done when I went in for new exhaust. Seemed reasonable at the time.

 

If you do manage to remove the nuts without breaking the studs you can replce the factory nuts with brass ones. These do not fuse themselves to the studs like steel ones do.

Good luck.

 

My truck did the same thing. Just fixed it a few weeks ago. It was the small tube from the air pump to the Cat. was rusted off. Got a new tube from the Ford dealer and installed it. A bit of a pain but not too bad. Noise is now gone.