> Is the heat on? On both my 1990 244 and my wife's 1993 245, there's a
> whistle or whine in the heating system, which generally only occurs at
> highway speeds. If I move the thermostat lever a bit it temporarily
> goes away.
Thanks for the replies and the time and thought put into them.
I apologize for the odd description I gave. I'm having an issue
relating it because I've never come across it before. The more I
listen to it the more it seems to sound like some kind of pressure
leak. To describe it another way, which is still rather vague, is to
liken it to a tea kettle. Once I've driven 50 mph or higher for a
couple miles I hear a build up to a steady whining noise. If I
release the throttle the whine slowly diminishes. Like taking a tea
kettle that is whistling off the heat. To describe the actual noise
the best I can do is compare it to the engine noise (the hum) you
might hear through poorly wired radio speakers, only clearer and
higher pitched. I know it seems juvenile but it sounds just like a
tea kettle going off in my car.
I thought about the radio, turned it off. Considered the air system,
turned off the fan and closed the diaphragm for the outside air. I
closed all the windows. Still get the noise.
I keep coming back to it sounding like some kind of pressure leak.
The problem with that is I can find no sign of any kind of leak much
less one that only happens at high speeds.
As for bearings, the sound is steady taking curves left or right, if
that tells you anything. The rest of what you've described is beyond
my knowledge so I can't confirm or discount it. Looks like I have
some reading up to do.
Mr. V - 08 Mar 2007 06:28 GMT
Perhaps one of the vacuum hoses to the heater and related ducting is
loose or has a hole in it.
mjc13<NOSPAM> - 08 Mar 2007 11:27 GMT
>>Is the heat on? On both my 1990 244 and my wife's 1993 245, there's a
>>whistle or whine in the heating system, which generally only occurs at
[quoted text clipped - 28 lines]
> my knowledge so I can't confirm or discount it. Looks like I have
> some reading up to do.
You can probably rule out wheel bearings. That leaves you with a
driveshaft carrier bearing complaining (they can do that for years
without failing), or, another possibility, an alternator bearing that is
just starting to go. We also had that happen, and the noise did *sort
of* fit your description. Or it's something else entirely. ;-(
Duane - 08 Mar 2007 12:13 GMT
Try this test. Pull the fuse (3#) and see if it goes away. Put the button
controls on recirculate (Far right button only) to keep outside air from
getting in and turning the fan.
Even though the fan switch is off it still spins at a low speed.
All my heater fan bearing failures in three 245's started with that whine.
My 90 currently has a small exhaust gasket leak between the manifold and
pipe leading to the cat that sounds the same. Only it goes away once
everything is hot.
Duane
Tim McNamara - 08 Mar 2007 15:17 GMT
> > Is the heat on? On both my 1990 244 and my wife's 1993 245, there's a
> > whistle or whine in the heating system, which generally only occurs at
[quoted text clipped - 11 lines]
> release the throttle the whine slowly diminishes. Like taking a tea
> kettle that is whistling off the heat.
That is exactly the sound our cars make. When it's happening, try
moving the slider for the heater.