Need help..gm/pontiac tech's cant figure this out.

[BigDaddy]

OK so 08 Grand Prix GXP. I am hearing what sounds like a bearing noise...best I can describe it is it sounds like hot water running through a pipe. They have replaced the altenator and the power steering pump. They tell me that per GM Tech support that if you can't hear it over the radio it's normal. Sorry don't buy that.

Symptoms.

1. At an idle..in gear or park if you turn the steering wheel a few degrees in either direction the noise cuts in and out.

2. If you gently press the gas pedal..especially in gear you can hear the noise get louder and almost sounds like a gurgling sound.

3. The intensity of the sound is not consistant sometimes it is very noticable and obvious..other times you have to listen closely to hear it.

It was not doing this when I bought it...probably around the 34k mark. Was thinking maybe heater core BUT wouldn't make sense with the noise cutting in and out when you turn the steering wheel slightly. Someone PLEASE give me some thoughts on this. It is not power steering fluid. My bumper to bumper is about up so I need to figure this out asap.

[nmp0098]

It could be something else in your steering setup besides the pump. How does it sound when turning? Louder or softer when driving? Is it only in certain positions, or only while you are actually moving the steering wheel?

[BigDaddy]

It could be something else in your steering setup besides the pump. How does it sound when turning? Louder or softer when driving? Is it only in certain positions, or only while you are actually moving the steering wheel?

Basically from an idle stand point you can here it. While you turn the wheel it stops and then when you stop turning the wheel you here the sound start again. When you are driving you cant hear it over the engine till you slow down below 10mph

[Carpepoon]

Have you had somebody else sit in the car while you stand outside with the hood up and listen? can you tell where its coming from? My guess would be something with the magnasteer system acting up.

[nmp0098]

I'd be interested to know what happens to the sound if the A/C compressor is on, because it will load the accessory drive like the power steering pump would. If you still here the sound, then it's more than likely in your steering system somewhere.

[BigDaddy]

Sound can still be heard with the AC on. I actually have the District Service Manager calling me this week as I sent GM a nice email and got a response in 2 hours. So now their corporate offices are involved. We shall see.

[06blgxplover]

yeah man let us know what happen with that, i got the same sound coming out of my gxp too.

[cerick08GP]

Well, I’m pretty sure I know what it is. By pretty sure I mean like 95%. The noise is your power steering pump, I’ll try to explain.

I’ll give my opinion in retaliation to your observations.

#1 That is the pressure relief opening and shutting in the pump. Not many cars are designed to steer a car that isn’t moving. To be brutally honest that is driving school day one stuff, stop doing that to your car. It isn’t good for any steering pump to do that.

#2 That is the pump cavitating from being speed up.

#3 The pump noises will vary depending on the temperature of the power steering fluid. As the fluid heats up the noise generally reduces to the point of being silent.

Power steering noises are pretty common in GPs. I noticed my pump makes more noise on my 07, than on my 02 GP. The truth is that GM power steering pumps are way over built and hence tend to be noisy at times. My car is noisy at cooler temperatures when I accelerate and turn at the same time. But after a taking about 3-4 turns in the morning it will be basically run totally silent. The good news is none of these noises means the pump is failing or even being damaged, it is just how they are. If you drive your car at reasonable acceleration rates and make about 4 turns (couple right and a couple left) then after a few miles of driving they tend to run silent. Now if your pump always makes noise, then IMHO you have a problem. Good luck.

[josup89]

I just bought an 07 GXP, and noticed a little hiss at cruising speed shortly after driving it off the lot. After closer observation I thought it sounded like valve clatter when the engine was in 4-cylinder mode. I refilled the car with 93 octane and haven't noticed it anymore. Dealership probably filled it up with cheap gas. This may be way off but I thought it was worth a try.

[Aceshigh]

I'm thinking if they replaced the power steering pump then the problem is not a relief valve opening. The valve is designed to only open if hard over. This is not what he's describing. I'm not certain what kind of rotary vane pump GM uses these days but I'd guess it's likely a spring offset cam so it does not have to use the relief valve at higher engine speeds.