Chirping From Back of Engine

[Devin]

I sometimes hear a chirping coming from the back of my engine. I thought it would be one of the belts but it comes from the rear. It's only noticeable at idle. When I put the 4a in I adjusted the valves cold via the FSM. Could this be the noise? Maybe I should adjust them hot? Otherwise, I'm thinking maybe one of the camshaft bearings?

[dlb]

i don't think it would be valves as they tend to make a rattle or 'clacking' sound. cam bearing could be possible. i had a bad wheel bearing on a VW westfalia that first presented as a squeak at a certain point in the wheel's rotation. at first, i figured it had to be the tire or something rubber but within a few weeks, there was a noticeable growl. had it replaced (i had formally sworn to not work on VWs anymore at that point) and the bearing was indeed toast. that being said, it's uncommon for bad bearings to sound like that.

the only other thing i can think of is a failing fuel pump but i don't have much experience with them so i don't really know. try using a long screwdriver as a stethoscope: put the business end on whatever you want to listen to and the handle right against your ear. it should magnify sounds and help you pinpoint exactly where the sound is coming from.

[Petros]

use a lot screw driver like a stethescope, press the tip to the engine and than push your ear against the handle end. It will help you isolate the chrip.

It could be a lot of things, bad fuel pump, bad pilot bearing on the back of the crank, something in the distributor perhaps.

good luck.

[Devin]

I can't seem to pinpoint the squeak. I don't think it would be the pilot bearing because I replaced that when I swapped the engine. It's like a soft 'ging ging ging" sound.

[dlb]

i don't think it's the pilot bearing either because it and the throw out bearing only spin when the clutch pedal is depressed. the screwdriver stethoscope trick didn't work for you? maybe try it at other parts of the engine. the sound could be reflecting around, making its origin misleading.

[Petros]

sometimes a vacuum leak or an exhaust leak can sounds like a tap or chirp. put your hands down around the exhaust manifold and feel for hot air blasting out somewhere. check all the gaskets and fittings, especially at the head pipe gasket.

Vac leak best found with some spray carb cleaner or starting fluid, the engine rpm will change where is sucks in the spray.

Either a vac leak or an exhaust leak will not be able to be heard with the screw driver or stethoscope trick since the sound is in the air, not within the engine.

My favorite "lazy man" way to find a difficult to isolate sound is to ignore it until it either gets so bad it is easy to locate, or what ever causes it breaks and than you know what to replace. if it never changes and never goes away, than you did not waste a lot of time locating it. I call that a win-win!

there is a hazard to this method however; it could cause a more costly repair later when what ever causes it finally fails, or leave you stranded. chance of that is not large, but it can happen.