Does this sound familiar to anyone???

[sojahseh]

So I've had my 85 for about 10 months now. I have gone though quite a bit getting it back on the road, and this forum has proved invaluable to that effort. I have more or less disassembled and reassembled large parts of the car, and it has been fun. Thank you all.

Now that the car is back, I have had an odd development. The motor has developed a strange whistle, that has gotten progressively worse over the past month. It presents as a steady, medium pitched whine, not unlike a balloon being choked. It is constant and not related to RPM. It also goes away while under moderate to heavy acceleration, but returns when ever the car is cruising.

The car does not run well when cold, and misses and bucks when under 3K RPM.

I did have the motor out, and stripped to the long block to remove a huge mouse nest on top of the motor, and replaced most if not all the important bits along the way.

I've stopped driving the car due to the noise level.

Any thoughts?


Thanks in advance...

[SteamWolf]

vacuum leak?
Spray some carb cleaner or WD40 around the motor with it running and listen for changes in idle speed.

[fanaudical]

Sounds like you have a noisy intake vacuum leak that is causing the mixture to get lean (hence the bucking) at partial loads.

[sojahseh]

Car cleaner sprayed around the engine bay? Tat will make the revs go up I'm assuming, due to the added fuel ?


I'll definitely give it a shot.

[emac]

Could the fan blade be rubbing the housing ever so slightly
Ernie 81sc

[sojahseh]

It's not the fan or alternator. I removed the belt and ran the motor briefly, and the noise was exactly the same.

[kodioneill]

Originally Posted by sojahseh

Car cleaner sprayed around the engine bay? Tat will make the revs go up I'm assuming, due to the added fuel ?


I'll definitely give it a shot.

Huge risk of a fire if you try that method.

[darrin]

The idle speed adjustment screw on the front/center of the throttle body caused this on mine -- was tough for me to track down. The screw has an o ring on it that dries up and, once dried up, air whistles by.

You should be able to confirm whether this is the source by capping the screw hole with your thumb and/or moving the scfew around a bit with the engine running/whistling to confirm you've found the culprit.

If this is the cause, easy to fix. I carefully screwed mine all the way IN first (noting precisely how many turns to full in), then backed it all the way out. I then applied some lubricant (silicone grease) to the existing o-ring, screwed the idle adjustment screw all the way back in and then backed it out back out by the number of turns noted in step 1 above.

No more whistle

Hope this is the cause or helps somebody out

[CCM911]

Are you running the stock airbox? Often times, a cone filter will whistle as you describe.

[sojahseh]

So after a little finagling I gave up and resorted to bringing it to someone with a smoke machine. Within 30 seconds we found out it's the intake gasket on cylinder #1, and also found a small leak on the MAF boot.

Definitely a moment of weakness, but such a timesaver.

Thank you all for your help and patience...

[sojahseh]

I've posted a WTD ad in the classifieds, but I just wanted to ask. Anyone have a set of black front seat belts they're willing to sell? PM me.




Thanks in advance...