I have a 1993 Ford Ranger 2.3 XLT 5 Speed manual. Ever since I bought it, it has a grinding noise only at mid-high rpm so at low rpm is doesn't make the noise and at high rpm near red line it doesn't make the noise. It's there in every gear including neutral when I rev it weather the clutch is engaged or not. Did a complete clutch job replacing the slave/throw out bearing, clutch, pressure plate, and the little input shaft bearing. Noise is still there. Upon further investigating it almost sounds like the grinding noise is towards the firewall while listening to it under the hood. I checked my exhaust manifold heat shield and it's not lose. I'm at a loss. I uploaded a video too so yall can hear it. Thanks so much!

https://youtu.be/I5Qzf6KR7E0

 

Sounds more like a rattle than a grind.

Maybe a heat shield somewhere on the exhaust going behind the engine bay?

If it is a rattle instead of grinding, it makes sense that it only happens at mid RPMs as the resonant frequency will make it happen only at mid-range and subside at lower and upper.

I would start tapping on any stuffs coming out the exhaust that's only bolted on or bolted nearby. Heat shields are the likely culprit.

Even way down the line. Not just the manifold.

Hope this helps.

 

Thanks for the reply. I'll double check but I've already checked.

 

Don't limit your search to just the exhaust. Look for any metal to metal stuffs. Wiggle, flick, tap, curse loudly...

Sometimes...just sometimes...

Catalytic converters make noise when the honeycomb elements inside become corroded from so many years of use and fall apart and rattle, but the rattle you have sounds like it's not a loose rattle, but a tight one.

I'm sure someone else might have a good guesstimation. I could be wrong.

 

I replaced the cat with a walker bolt on unit. So it's not that. It didn't have a cat when I bought it. Noise never changed

 

I know you've already checked it. I had a similar noise that would resonate at certain RPMS. Just by process of elimination I tried one of these around the heat shield, just snug enough to hold a bit of tension on it. Got lucky and that was it, the noise went away. My heat shields were tight and only made that noise in conjunction with certain RPMS. Worth a try.

 

Thanks but I've put my hand on that heat shield while pulling the throttle and making that noise and the noise didn't change. Where exactly did u put that clamp?

 

I wrapped it around the heat shield and exhaust pipe and just tightened it until there was a little tension on it. I guess I just got lucky.

 

I'm out of ideas, MrT, but let's narrow it down.

How about taking off the heat shield(s) to eliminate that making the noise? If it disappears, then we have the source. If it doesn't, we move on to another.

 

Ok man when I get a chance this week ill see if I can remove it. Isnt it tac welded on

 

OK i tried everything you guys suggested, but the strap on the manifold and everything. Still makes the rattling noise. It is literally coming from where the egr comes into the intake. back behind there. ive revved the engine from under the hood to get it to constantly make that noise and looked and felt around and nothing seems out of the ordinary. is there a possibility that the noise is coming from under my valve cover or my intake manifold? Any pointers or ideas will help because i have no clue whats causing this annoying loud noise. Thanks a lot guys

 

Also just finished doing timing belt and timing belt tensioner, water pump, thermostat, oil change, coolant flush etc. Nothing changed the noises

 

It does sound like something small.

You said a clutch job was done.

I'm thinking maybe something inside the bellhousing not tightened down all the way? Being "back behind there" and all.

Are there any brackets back there that may have been disconnected for the clutch job?

When you ask if the noise may be coming from your intake or valve cover...has there been any work to that before and then the noise started?

If you'd like to unbolt all that to check, it only costs you time.

It doesn't sound like valve lash. That's more of a ticking and throughout the RPM range...not just midrange.

 

Sounds like a tight dry ball bearing. Check the engine peripherals. Sounds can do weird things. Have you tried to use a stethoscope to help pinpoint the spot?

 

The truck didnt need a clutch, the whole reason i did the clutch job in the first place was because i thought it was a bearing (pilot bearing or throw out bearing or maybe a loose pressure plate etc) although the bearings were in poor shape, replacing them didnt change the noise. I didnt see anything unusual while doing the clutch (input shaft was nice and tight and very little play etc) my worst fear is an internal transmission bearing but wouldent that not cause the rattling while im in neutral? Remember it does it in gear and in neutral when i rev it. I havent got a stethoscope to pinpoint it yet but its most definently near the rear of the engine. Maybe ill post another video later of where its coming from. Thanks so much for your help guys.

 

Good news. On sunday night i was very confused on what the noise could possibly be. I've searched around and some people suggested that it could be spark knock of some sort. So on Monday my gas tank was nearly empty so i added 5 gallons of shell v power 93 octane. Tuesday morning it seemed like the noise didnt happen for as long as it used to throughout the rpm range. And that evening when I drove home from work, the noise conpletely went away and i didnt hear it ONCE my entire drive home. Ever since i bought this truck 8 months ago it ALWAYS made this noise and now it is entirely gone. Im super stoked but i found this to be extremely bizzare. Im almost convinced that it was a coincidence and it somehow went away by itself but thats extremely unlikely. So i guess if anybody else has trouble with this kind of noise, try some high quality high octane gas and it might go away. Now im curious if i put regular 87 octane gas in if the noise will come back. Thanks for all of your help guys. God bless