I recently purchased a 2012 Jetta Sportwagen TDI. Recently after about an hour of driving I start to hear engine noise through the stereo. It comes through the speakers on FM, AM and Bluetooth. After a while it gets so bad it sound as if the speakers are blown! When I shut the car down and let it sit overnight, the process starts over again, first everything is fine then after about an hour I start to hear the noise again. One additional problem I noticed is that my side view mirror LED turn signal had been dim lately and may have started around the time of the stereo problem. The noise doesn't change with the blink of the turn signal or anything else I've tried, only changes with the RPM of the engine. A friend suggested a ground or a resistor? Where would I look for that? Any other ideas? Thanks!!!!
Engine noise through stereo
- Thread starter Jarhead96
- Start date
gmcjetpilot
Veteran Member
Yes I have an idea.... First it is not normal and it has to do in general with two issues:
1) Alternator has failing rectifier, which changes AC to DC...
2) Poor ground or grounds not only radio but battery to car and body grounds.
Both of these create noise in the power feed to the radio which come out in
the audio. Was this car wrecked? If they left out some grounds it might be
the issue.
How to fix it... systematic trouble shooting, which takes some skill and test
equipment. I would recommend you go to Auto Zone, Advanced Auto or
O'Reilly auto parts. They all offer free charging system test in the parking
lot. They will test your battery as well.
Then you can go through the wiring, wiggle connectors, remove and
reconnect, check ground from battery and frame grounds.
There are aftermarket noise filters you put in the power feed to the radio.;
that is a Band-Aid. They do work but you are not fixing the problem.
Does the noise have a frequency that changes with RPM? That is an
alternator issue. Again the rectifier changes AC to DC... alternating current
mikes the whine in the audio and it changes with engine RPM. It can be
from other electrical items, blower motor or fuel pumps....
1) Alternator has failing rectifier, which changes AC to DC...
2) Poor ground or grounds not only radio but battery to car and body grounds.
Both of these create noise in the power feed to the radio which come out in
the audio. Was this car wrecked? If they left out some grounds it might be
the issue.
How to fix it... systematic trouble shooting, which takes some skill and test
equipment. I would recommend you go to Auto Zone, Advanced Auto or
O'Reilly auto parts. They all offer free charging system test in the parking
lot. They will test your battery as well.
Then you can go through the wiring, wiggle connectors, remove and
reconnect, check ground from battery and frame grounds.
There are aftermarket noise filters you put in the power feed to the radio.;
that is a Band-Aid. They do work but you are not fixing the problem.
Does the noise have a frequency that changes with RPM? That is an
alternator issue. Again the rectifier changes AC to DC... alternating current
mikes the whine in the audio and it changes with engine RPM. It can be
from other electrical items, blower motor or fuel pumps....
Thanks! That gives me a good start. Never thought of the alternator. The noise changes with the RPM's, nothing else seems to make a difference (fan, a/c, turn signals, usb charges etc.) It's starts after about an hour driving the car and progressively get worse. If I stop and turn the car off for a while, the radio will sound fine after restart then start making noise again. The car was in low speed rear end collision according to the previous owner but the noise only started a few weeks ago. I've owned the car since April.
UPDATE:
Took the car to Advance Auto, they did diagnostic on battery and charging system...all good.
Took apart the drivers side mirror, found corrosion in the dim LED indicator and disconnected (part hasn't arrived yet)
During a 4 hour drive this am, same problem started after about an hour and got progressively worse. Sat in traffic for about 30 minutes and realized that beginning hour 3 the noise had stopped and was fine for the rest of the trip. Pulling in front of my house I turned the radio to FM (usually use bluetooth) on an unused station. When I hit the hazard lights I did hear a popping through the static on the radio station. Could this indicate a bad turn signal relay?
Took the car to Advance Auto, they did diagnostic on battery and charging system...all good.
Took apart the drivers side mirror, found corrosion in the dim LED indicator and disconnected (part hasn't arrived yet)
During a 4 hour drive this am, same problem started after about an hour and got progressively worse. Sat in traffic for about 30 minutes and realized that beginning hour 3 the noise had stopped and was fine for the rest of the trip. Pulling in front of my house I turned the radio to FM (usually use bluetooth) on an unused station. When I hit the hazard lights I did hear a popping through the static on the radio station. Could this indicate a bad turn signal relay?
Ok well I replaced the DS side view mirror turn signal which was dying. Also checked the battery ground....looked good. Checked the alternator with multimeter, under load steady at 13.7 and no load at 14.0. Checked the rear taillights and turn signals, found that previous owner must have had a trailer light hook up tapped into the wiring. Looks like someone used liquid tape to seal them up but it was cracked and bare wire was showing. Taped everything up and was hoping that fixed it but no. Drove again this AM, after about an hour the noise started again. Got into about an hour worth of stop and go traffic then it stopped and was fine for the rest of the ride (about an hour). Is there something VCIDs might help with diagnosis??? Next stop the stealership 