1994 Subaru Impreza Irregular Whining/Whistling Noise

MATOAKA

MEMBER
1994 SUBARU IMPREZA
4 CYL
AWD
AUTOMATIC
230,000 MILES

Sometimes, when I hit a bump or pothole, or when I'm climping a hill, a high pitch whine starts up. It gets higher with speed and dies when I come to a full stop. Then it either stops completely or sometimes it starts up again as I pull away. Hardly ever happens in the winter, just during mild or warm weather. Sounds like it's coming from engine compartment on passenger side. Doesn't sound like a belt slipping. And, of course, it never does it when a mechanic is in the car.

1 Reply

ZACKMAN

MECHANIC
4,202 POSTS

There are two different kinds of engine whines: mechanical and electrical.

Mechanical: Your hydraulic lifter can make a tapping sound under certain stress condition. It will vary in pitch depending on the engine speed.

Electrical: Your fuel injector, plug wire, and coil will whine if the electrical connector is not fully seated (not grounding correctly). You also have a grounding strap on the passenger side. It will also whine if the connection is not tight. It will also vary in pitch depending on the engine speed.

In your case, I am going with electrical noise. Check and make sure that all electrical connectors are tight. Just give all of them a "push" to see if they are in snug.

The next time it happens, immediately pull over when it is safe to do and quickly get under the hood to investigate.