Whining sound when starting car

kingbarley · Post by **kingbarley** » 04 Jun 2010, 16:20

Hey everyone, I've been trying to eliminate any and all issues with my 850R lately and this one has been bugging me for a few months now. Whenever I leave my car sitting overnight or for a decent period of time and then start it up and start driving, it makes a whining sound when accelerating pretty much until it reaches its normal operating temperature. What could be the cause of this? I just want to make sure it's not anything serious that could possibly damage other parts on my car in the future. Thanks in advance!

Post by **JDS60R** » 04 Jun 2010, 17:21

Whining that stops once heated up usually reserved for a vane type pump. Think- power sterring or transmission . Open the hood and use a mechanics stethescope or long screwdriver held to the trans and power steering pump cases to locate the whine. Regardless which unit it is you should repalce the fluid.

I beleive the air pump in the 850's has been known to make a noise but I am unsure if it is similar to the noise a pump would make. You may want to check power steering and transmission fluid levels before checking.

Post by **vjaneczko** » 04 Jun 2010, 17:36

When the air pump is spinning, it's just a small fan spinning really, really fast - and sounds like it, too. Usually you can hear it when at a dead stop, but once you hit 10 or 15 mph, it's pretty much covered up by road noise. Sometimes it'll also spin after you shut the car off - it's mounted under the battery so you can't miss it when it's on.

One thing you can do to troubleshoot the air pump is to crawl under the battery and you'll see the pump and its relay, all connectedd on the same mounting bracket. No need to jack it up, it'll be right smack in front of your face. There's a wire from the pump that runs to the relay. Pull it and see if your noise goes away. One word of caution: if you pull it, you may throw the C.E.L. because the air pump is part of the emissions system.

CHicks · Post by **CHicks** » 04 Jun 2010, 19:06

My 96 850 was whining from a couple of places. I disconnected the wire to the airpump under the battery and got rid of one. No check engine light yet but it's only been a week. The other, more annoying whining sound was the headlight wiper motor. Apparently it was stuck on without the wiper blade moving. Disconnected that as well and it's pretty quiet now.

kingbarley · Post by **kingbarley** » 04 Jun 2010, 19:28

The weird thing is that the car whines during startup and acceleration, but after it reaches the normal temperature the sound goes away. Could it be possibly related to the thermostat?

Post by **JDS60R** » 04 Jun 2010, 19:54

Nope - not the thermostat.

The thermostat only moves a very small distance. It doesn't make any noticeable sound. In order to get a whine it has to have a continously spinning component rubbing against a component that does not spin. Like a transmission pump,power steering pump, electric motor etc.

CHicks · Post by **CHicks** » 04 Jun 2010, 20:37

The air pump under the battery that I disconnected, according to what I read, is only active at startup and stops once the engine warms up a bit.

Post by **Ozark Lee** » 05 Jun 2010, 05:21

The air pump under the battery that I disconnected, according to what I read, is only active at startup and stops once the engine warms up a bit.

That is correct. Its function in life is to get the catalytic converter up to temperature quicker.

...Lee

kingbarley · Post by **kingbarley** » 05 Jun 2010, 09:32

okay so i just started my car this morning after about 12 hours of inactivity and i narrowed it down to the sound only happening when i'm pressing on the accelerator. would that make it a transmission problem? i had a friend feather the accelerator while i poked around the engine bay and the sound seemed to be coming from the back of the engine, but i might be wrong. Any ideas?

Post by **JDS60R** » 05 Jun 2010, 11:14

Sound can bounce around. With it being rpm induced I would say Power steering, trans or turbo.

Keep listening. Use the stethescope method and report back.