2000 Discovery 4.0 with almost 157K. There is a loud squeal coming from the engine somewhere. It sounds like from the left hand side towards mid to rear engine. It is some what intermittent and fluctuates during idle or it can remain constant. Same issue when driving and when you reach road speeds then left off the gas pedal so you stay at the posted speed. It goes away when you rev the motor or during acceleration at any rpm. It just totally disappears but comes back after you let off the gas pedal. The sound is similar to hearing a bearing going out on a pulley although much louder. As soon as you give the engine a little gas the noise goes away. The noise was going on before I did the work on my truck which I listed in another post.
Things I've done to troubleshoot.
- Re-torqued the intake manifold. As always in a proper sequence and specs. (Still Squeals)
- Removed the serpentine belt to test everything on the front of the engine. (Still Squeals)
- Sprayed carb/intake cleaner around the gasket of the intake manifold and the RPM remained the same. Didn't drop nor increase.
- Sprayed carb/intake cleaner around the throttle body, all vacuum hoses, the SAI, around the heads, Everyplace I could think of with a vacuum. No decrease/increase of rpm.
- All coolant and oil levels are good with no mixture. There are no leaks from either.
- A few years ago on another truck I had a champion spark plug pop a hole in the ceramic and made a somewhat similar noise. When you looked at the plug it looked normal. But it was leaking. So I checked them and they seem fine on both sides of the engine.
Zero issues with starting the engine. It has always started and ran great. The transmission works as it should. I thought maybe the torque converter or pump but then again the transmission works great.
Bad lifter? I would think the noise would get louder with rpm. Wouldn't it just get louder with rpm? Maybe it pumping up at higher rpm gets rid the noise?
Ok that's what I've checked into. I did the internet search and no cigar. I could use some help. Appreciate any.
Things I've done to troubleshoot.
- Re-torqued the intake manifold. As always in a proper sequence and specs. (Still Squeals)
- Removed the serpentine belt to test everything on the front of the engine. (Still Squeals)
- Sprayed carb/intake cleaner around the gasket of the intake manifold and the RPM remained the same. Didn't drop nor increase.
- Sprayed carb/intake cleaner around the throttle body, all vacuum hoses, the SAI, around the heads, Everyplace I could think of with a vacuum. No decrease/increase of rpm.
- All coolant and oil levels are good with no mixture. There are no leaks from either.
- A few years ago on another truck I had a champion spark plug pop a hole in the ceramic and made a somewhat similar noise. When you looked at the plug it looked normal. But it was leaking. So I checked them and they seem fine on both sides of the engine.
Zero issues with starting the engine. It has always started and ran great. The transmission works as it should. I thought maybe the torque converter or pump but then again the transmission works great.
Bad lifter? I would think the noise would get louder with rpm. Wouldn't it just get louder with rpm? Maybe it pumping up at higher rpm gets rid the noise?
Ok that's what I've checked into. I did the internet search and no cigar. I could use some help. Appreciate any.