How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Matt Your Own Question
Matt
Matt, Engineer
Category: BMW
Satisfied Customers: 20608
Experience:  Mechanical Engineer with 20 years experience in the auto industry, 8 yrs in formula 1 engine testing
12772297
Type Your BMW Question Here...
Matt is online now
A new question is answered every 9 seconds

I' Vine. I have a 1990 325i conv. My radio produces a

Customer Question

Hi I' Vine. I have a 1990 325i conv. My radio produces a hi pitched shrill noise . intermittently where do I look or what do I replace. Thanks
Submitted: 1 year ago.
Category: BMW
Expert:  Matt replied 1 year ago.

Hello

this is likley to be an interference issue with an electrical noise source contributing to the squeal

I'd 1st suggest checking that condition of the ignition / spark leads Check their resistance of the spark plug leads ( 13-15Kohm / metre) and replace if anydoubt or high resistance - Also replace the spark plugs if any of them failthis checklist:

http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp

there should also be a capacitor / damper on the coil power wire these look like little cylinders with 1 wire running to the power if the wire is broken or the part missing then your radio interference will increase markedly

also check the condition of the small earth wires that run out of the engine bay loom and terminate onto the engine with ring terminals

also check the condition of the fuse in the radio power wire if its connections need to be bright and clean with no resistance to the fuse

Customer: replied 1 year ago.
Matt thanks for your answer which confirmed my own theory. But I was expecting amore narrow answer.
I'not a mechanic so need more infomation.
vince
Expert:  Matt replied 1 year ago.

Hello Vince

Ok 1st thing to check is the condition of the plug wires as they are the biggest influence

then check for the coil capacitor / damper and replace as required

Expert:  Matt replied 1 year ago.

Hi

do you still need help

Bear in mind thatt he site takes a deposit from you at the beginning and this is held by the site until you rate my answer at which point the cash is split between the site and the expert. so if my answers have been helpful please rate my answer.

Related BMW Questions