1995 850T noise right front. MVSOLVED wiper motor

Seamonster · Post by **Seamonster** » 02 Jun 2014, 17:11

Hello all,

My 1995 850 Turbo wagon has developed a humming tone that I don’t recognize, and searching this and other forums hasn’t led me to an answer. It seems to emanate from the right front of the engine compartment, down low, near the washer filler. It occurs whether the car is moving or not. When the engine is running, the tone is at approximately 330 Hz (or a middle E on a piano). The car seems to be performing normally otherwise, and a check for fault codes produces none.

Complicating the diagnosis, the tone is similar to one that can be heard when the key is turned to position I, before the starter is even engaged. But that tone is at approximately 280 Hz (middle C#), and it’s not entirely clear to me that it’s coming from the same source. They do sound similar though, apart from the approx. minor third difference in pitch.

It sounds like it might be produced by a fan or a motor, but it is not the fan that comes on when hot, and it has more pitched tone than whirring noise – so I’d say more likely a small motor than a fan.

Thanks for any feedback you might offer.

– Kraig

Post by **kahl** » 02 Jun 2014, 18:03

I had a similar motor sound turned out to be the headlight wiper motor. no movement on the wiper arm shaft, motor just buzzed all the time. unplug motor and see if sound goes away.

Post by **abscate** » 02 Jun 2014, 18:07

If it isn't A440 you need a tune-up.

Sorry - that was too easy

The Idle Air control valve makes noise on these cars, I believe (since I don't have one)

Post by **Ben850** » 02 Jun 2014, 18:39

abscate wrote:If it isn't A440 you need a tune-up.

Sorry - that was too easy

The Idle Air control valve makes noise on these cars, I believe (since I don't have one)

OK Abscate, you are relieved of duty on the charges: Count #1. Bad Pun.
Count #2. Do not own an 850 Wagon.

Everyone that owns one knows that you tune to B flat on a Turbo wagon. A 440 doesn't quite do it.

Alright. Levity aside, there are two wiper fluid pumps in that area (for a Wagon), as well as the headlight wiper motor, (if installed).
So three motors in total, with the possibility of a stuck solenoid of some sort. Try to pinpoint the exact location.

Seamonster · Post by **Seamonster** » 03 Jun 2014, 00:49

Who knew there were such comedians here? (But yeah, Bb is what *wind instruments* tune to, which is what the turbo is).

Actually, the notion that it's a motor or stuck solenoid relating to the headlamp washers does make some intuitive sense. I discounted the headlamp washers because they have never worked in the six years I've owned the car. But then this car has some history of spontaneous self-repair – like the light beneath the transmission selector didn't work for three years, then one day started working just fine.

It shouldn't be the pump for the main washer, as I can hear that separately when I turn it on; but for some months that main washer motor has run, but nothing has "spritzed." Given there's been something amiss with the main washers for a while now, could the headlamp washers suddenly be affected? E.g., if they're on the same circuit, some incorrect impedance might eventually trigger a cascading failure(?)

I'll have to get out in the afternoon to give it a closer look, and see if the headlamp wiper motors weren't already disconnected long ago (as I seemed to recall).

The replies so far have been thoughtful, if not pitch-perfect.

Post by **abscate** » 03 Jun 2014, 01:41

Get a French Horn and find the exact location of the noise using it as a stethoscope.

Sorry, I got confused by Dennis Brain, ca. 1950s...your Fr. Horn should look like his..

Seamonster · Post by **Seamonster** » 03 Jun 2014, 15:42

Kahl, Ben850 et al,

Thanks, the tone went away when I unplugged the headlamp wiper motor. (So much for my big plans of using the wiper as a metronome.) I hope this doesn't adversely affect the overall load on the wiper circuit.

Is there a simple way of flagging this thread as "solved", for future readers? (Notice that I updated the subject line here to include "Odd hum, right = headlamp wiper motor".)

Now if only I can figure out why the nearby windshield washer motor hums when switched on, but does not squirt liquid....

instarx · Post by **instarx** » 03 Jun 2014, 18:32

Seamonster wrote:Kahl, Ben850 et al,
Now if only I can figure out why the nearby windshield washer motor hums when switched on, but does not squirt liquid....

...because it can't sing?

Post by **kahl** » 03 Jun 2014, 19:00

I would suspect the motor shaft that penetrates the impeller is stripped.

Post by **abscate** » 03 Jun 2014, 19:34

instarx wrote:
Seamonster wrote:Kahl, Ben850 et al,
Now if only I can figure out why the nearby windshield washer motor hums when switched on, but does not squirt liquid....
...because it can't sing?

Sounds like it needs some Handeling