Jump to content

Quiet high pitched noise when parked up.


Mikey
 Share

Recommended Posts

The other morning my 300Tdi auto wouldn't start. The battery was very low, just enough to heat the glow plugs but not enough to turn over the engine. So I walked to work. When I got home the battery was totally flat, not even enough power to light up the dash lights. I had no previous warning of the battery getting low, vehicle was fine the day before.

I didn't have time to investigate possible causes so I bought a new battery. Anyway today whilst under the bonnet I noticed a quiet but high pitched whistling type noise. (ignition was turned off). The noise seemed to come from the general area of the alternator, but not certain.

I am concerned that something may be constantly draining the battery. Can anyone throw any light onto a "possible" problem.

Further info: The vehicle is fitted with a non standard CD player, and a non standard imobilisor and alarm, also Range Rover electrical seats. I assume that all these are wired corretly. The vehicle had an MOT over the weekend, don't suppose they would have disturbed anything electrical?

Link to comment
Share on other sites

Sounds like the alt could have a dead regulator.

To track down a current drain, remove one of the battery leads (-ve is safer) and put an ammeter between it and the battery terminal. Then disconnect things (or pull fuses) until the current draw drops to "not much". I'd start by disconnecting the alternator charge wire to see what happens. You should have less than 1 amp draw, give or take dependent on alarms, interior lights, stereo memory, etc.

Link to comment
Share on other sites

The other morning my 300Tdi auto wouldn't start. The battery was very low, just enough to heat the glow plugs but not enough to turn over the engine. So I walked to work. When I got home the battery was totally flat, not even enough power to light up the dash lights. I had no previous warning of the battery getting low, vehicle was fine the day before.

I didn't have time to investigate possible causes so I bought a new battery. Anyway today whilst under the bonnet I noticed a quiet but high pitched whistling type noise. (ignition was turned off). The noise seemed to come from the general area of the alternator, but not certain.

I am concerned that something may be constantly draining the battery. Can anyone throw any light onto a "possible" problem.

Further info: The vehicle is fitted with a non standard CD player, and a non standard imobilisor and alarm, also Range Rover electrical seats. I assume that all these are wired corretly. The vehicle had an MOT over the weekend, don't suppose they would have disturbed anything electrical?

I have a similar noise that comes from my alternator but only when the ignition is on, if I turn the ignition off the noise stops and it is definitely from the alternator. Not sure what your fault is but I don't think it should be doing it when the ignition is off. Sorry I can't be of more help.

Gaza

Link to comment
Share on other sites

OK, the alternator is still making the noise when the ignitions is turned off. Forgot to say that the warning light does not come on at all when ignition turned on. I will try to get it seen in the morning by an auto electrician.

Another question, is the regulator complete with the alternator or a seperate part?

Link to comment
Share on other sites

Another question, is the regulator complete with the alternator or a seperate part?

Without seeing it I can't be 100% but many are - Lucas and Bosch often are. Why pay an auto electrician? This could involve two screws and a connector... I think the regulator packs are ~£12 new.

Link to comment
Share on other sites

I have just checked, I have a Magneti Marelli A1271 - 100Amp fitted. Been informed that no spares are available other than brushes and bearings. Replacement is aprox £160. A company on internet has alternative model availlable for aprox £65 made by torq x or similar name.

My dilemma right now. Existing alternator is actually charging when running, but makes a strange buzzing/whistling noise when not running, and is probably discharging the battery slowly. So do I do nothing and cross my fingers. Or do I buy a new item or maybe even a cheap alternative?

I don't have too much to spend at the moment.

Link to comment
Share on other sites

Or you could hunt round eBay / scrapyard for a replacement - as long as it mounts the same way and has a similar pulley you can fit pretty much any alternator. A mondeo alt will be cheap and kicks out 90A.

I guess I was coming around to that I idea, cheers.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy