Problems with my car audio

Hi, I have a 94 BMW 3 series with an Alpine system. I am having two issues with this audio system. It's the original that came with the car. It has a tape deck and radio only (I am old). Problem 1, when I turn up and down the volume it cuts in and out on the driver side speakers only while adjusting it. Problem 2, when I play tapes it sometimes makes a squealing sound while it's playing. I checked the tape on my home system and it's fine. But not all tapes do it. Thank you for your help.

The cutting out is caused by a dirty volume control. They are easily cleaned in the decks of this era. WD-40 sprayed into the openings of the control works wonders. You must take cover off the top of the deck to access the actual control. (Behind the face, do not try to spray it in the knob area) Is the squeaking sound coming out of the speakers or out of the mechanism?

Thank you for the reply. I am not sure if I can get the cover off to have access to the volume control. It has security screws. The squealing is from the speakers and seems to only do it on one or two tapes.