Hey everyone,

1982 244 B21 2.1L KJet 132k miles

Car has been running great after all the work I've put in over the last year, but over the last six weeks or so I have started hearing this high pitched whine, almost like a whistle. I can only hear it when the car is idling, and it seems to come and go, it isn't constant. Also seems to be a bit louder when the ambient temp is hotter. The pitch frequency doesn't change with throttle inputs, it only goes away when I rev the motor and then returns when settled back into idle. When I shift into a drive gear, the sound disappears completely. At speed on the road I cannot detect anything. I have never heard the sound other than being in park or neutral at idle.

After searching underneath the car and in the engine bay for some time, it seems to be coming from the top front of the motor, in the area of either the camshaft or possibly intermediate shaft. I first replaced the timing belt tensioner, belt (since I was there) and water pump, thinking it was one of those, and while the sound seems to have diminished in volume, it's still there.

I have not been able to find anything resembling these symptoms while scouring the boards. My thoughts now are possibly intermediate shaft bearings or camshaft bearings? I have never opened up one of these motors, or any motor for that matter, so my experience in diagnosing internal engine sounds is limited.

Here is a link to a video I made just the other day that highlights the issue quite well. I have since installed the new timing belt tensioner and water pump so it's not quite as loud as the video, but still quite noticeable:

https://www.youtube.com/watch?v=lGZkMkkzH_k

Thank you all in advance for your suggestions and advice!

Fan and power steering belts make uncredibly loud sound at time on my 1982.

When I want to check and quit these down instantly I spray a small jet of water on them. I sleep better after. The sound sometimes really makes me worry.

My Idle Air Control valve hose is collapsing and it make a strange sound only at idle.

Hi,

Check the timing belt idler.


Goatman

Forgot to mention for what it's worth...my 240 is one of the last equipped with the BW-55 three-speed auto. I tend to drive fast on the highway (75-80mph) and was doing about 500 miles a week to work for the last 11 months. Maybe the sustained high RPM's could be a clue towards diagnosis.

Other than the ringing, she runs fantastic...as smooth and powerful as a B21 can be.

Hi there,
I agree it could be a bearing with a sliding member instead of one that is rotating properly.
The sounds either goes away if it begins rolling or the frequency goes higher than you ears are capable of hearing.
If you have a dog they may know that car in particular than others you drive. They just don't talk about it. (:-)

If it were my car I would be removing V-belts one at a time until the sound goes away. You can remove all the belts and run the car for short periods.
Removing the A/C knocks out one half real quickly.

Changing the tension of a belt can change the way it transmits sound. The power steering pulley itself can act like a speaker cone and amplify the rubbing sounds that a belt makes entering or leaving the groove. As belts age they make squishy to a squeaking sound.
The power steering does not use a roller bearing so that leaves three.

The Alternator, water pump and the air conditioner. The A/C will stop squealing if the A/C becomes engaged because the outer part of the bearing will be turning equally with the compressors shaft.
The water pump it a very robust and lengthy bearing in comparison to the alternators two narrow ball bearings. In my experience with water pumps they will make a clunky/rattling or clacking sound.

So I will say it's a better chance of it being the alternator's bearings doing the high pitch due to their size. Electrical load can very the pitch somewhat and the more RPM may, in affect, change that.

You say it sounds high but a high pitch echos and can warble. Several things are in the front of this engine and this sound is harder to trace. The timing belt tensioner was my first guess too!

You might try putting the microphone of your recording device on the end or into a tube to get more directivity.
I have never tried this but I envision using a paper towel tube with some or very few turns of towels left on it for insulation but smaller, if you know what I mean.
I own a stethoscope but down there you might want to listen to the fan clutch area or the timing cover again.
Just throwing around another possible sound, in that, a belt guide washer on the crank could be singing if it's getting rubbed up against. There might be an alignment problem.
The B21 does not have a harmonic damper but straight out metal pulleys too.
Doesn't it have a metal timing cover too? My '78 does. Something could be off in there... just saying!

I'm intrigued to know what you find!

Phil

Uncle Phil machine man writes:

"Changing the tension of a belt can change the way it transmits sound. The power steering pulley itself can act like a speaker cone and amplify the rubbing sounds that a belt makes entering or leaving the groove. As belts age they make squishy to a squeaking sound.
The power steering does not use a roller bearing so that leaves three."

++++ 1 ...

I've heard this sound before on the pre-harmonic balancer overhead cam redblocks. The two-number over head cam redblock engines. With the Saginaw power steering pump as you have. Yet v-belts can make nose on the pulley no matter what, with proper alignment and new accessory bushings as you installed. With the engine stopped, closely look and also feel the texture of the v-belt where it contacts the pulley.

A v-belt or (far less probably) the timing belt is riding against the edge of a pulley. The sound is where the belt edge lifts away as it leaves the pulley or t-belt gear cog edge guide. (The cam gear or, less so, maybe the crank timing gear guides. Yet the small ridge and under some material stack compression make resonance less probable.)

A spray bottle with some water in it and spray on the uptake side of the v-belt pulley, or the inside of the belt itself. Maybe will quiet the ringing sound momentarily so you know it is the V-belt to pulley contact. And not a bearing.

Else, if not, maybe a pulley bearing starting to sing, and they do in different ways as wear formation is sort of unique in each instance, yet generally the same. As with the A/C clutch pulley bearing.

The power steering pump, as Uncle machine man says, acts as a speaker. It resonates sound quite well, when looking at it. The material and design.

Else, NICE B21F engine bay. I mean it sparkles in there! Lovely valve cover and nice oil fill cap! You motor and transmission mounts are not so new? It appears the engine sets rearwardly a bit? Maybe not ...

Always wanted a white, blue, rod brun (pumpkin [pie]?), orange, and yellow 240, 140, 164. Still wants.

You make me miss the 1970s 240s. K-jet and all. =^(....

Happy Sat-Your-Day!

Earl and Lady Grey Tea, Hunny, 1% Milk, and Duffed.
--
Give your brickboard.com a big thumbs up! Way up! - Roger Ebert.

Thanks for your input Phil, interesting thoughts.

I did also forget to mention that the alternator is new, along with all the drive belts and water pump (less than 1k miles on all of them). The fan clutch is also fairly new with 5k miles on it. Timing cover is the plastic one-piece unit. I really shoot for proper belt tension these days...my younger self always incorrectly tightened the sh*t out of them.

Another side note, I fitted the alternator and power steering pump with poly bushings when I got the car 18 months ago to remedy the constantly squealing belts. The rubber ones were blown out and oil soaked.

I will try the paper towel dowel mic method, along with removing belts one at a time and see what I can come up with.

I can definitely see how the pulleys could act as amplifiers for belt vibration...I'll re-check and re-seat the crankshaft pulley bolt stack-ups and plate washers too and see what that does.

Thanks! I'll report back with my findings

Your description of a "ringing" sound makes me think of the stamped shield employed in the crankshaft timing gear system. Is it possible it is not seated and rattling around? -- Dave