[jinu_joseph]

Hi Folks

There was this sound coming from the car under the bonnet (Hi speed whirrrrrr... kind of sound). This sound was amplified if i pressed the accelerator in neutral.

Took the car for servicing at GM authorised servie centre - SC AUto, Thane (The new Udit motors). When i went back to collect the vehicle in the evening the service advisor told me that the noise was originating from the PS pump. The PS oil level was low and there was some PS oil found in the pump, so the pump was going bad (I did not understand this part, so i took it at face value). He said he had topped up the oil and the noise would be gone. He said if the noise came back then the pump would need to be replaced but i could continue to drive it till the next service that is for another 5000 Kms even with the noise. He confirmed to the following:

1. There was no leak in the PS system.
2. There would be no mechanical damage to the car if I continue driving with this Pump till the next servicing.
3. The only inconvinience would be the noise and nothing else

He said the pump itself cost about 15k, so it was better to delay.

This problem started after the belt was changed as part of the last service (30,000kms). Not sure if it is related.

So guys what do you say is he right or is he giving me BS.

PS: i got it back from servicing on Sat. and today the noise has started again.

[gpa]

Originally Posted by jinu_joseph

There was this sound coming from the car under the bonnet (Hi speed whirrrrrr... kind of sound). This sound was amplified if i pressed the accelerator in neutral.

Took the car for servicing at GM authorised servie centre - SC AUto, Thane (The new Udit motors). When i went back to collect the vehicle in the evening the service advisor told me that the noise was originating from the PS pump. The PS oil level was low and there was some PS oil found in the pump, so the pump was going bad (I did not understand this part, so i took it at face value).

From what you have mentioned, it does look like the steering system is leaking fluid which could have put an immense strain on the pump leading to the whirrrr sounds that you are now facing. Ask your service centre to check the tension of the belts for the right amount of tension and play.

Normal operating pressures within a power rack generally do not exceed 150 psi when the wheels are straight ahead. In an easy turn, pressure can increase to 300 psi, and up to 700 psi in a tight turn. The highest pressures are usually encountered when parking. If the wheels are up against a curb or if the steering wheel is turned hard against the stop, it can climb to 700 to 2,000 psi depending on the application.

Based on these high pressures encountered, hydraulic powered steering racks can develop fluid leaks. Seal wear can allow fluid to seep out of the power cylinder into the end bellows on the rack. The bellows are not designed to hold power steering fluid.

The presence of power steering fluid in either bellow, therefore, means the rack is leaking internally and needs to be replaced. If nothing is done about the problem, the bellows will continue to mushroom with fluid until one or the other bursts, releasing the fluid that has been mysteriously disappearing from the pump reservoir.

[jinu_joseph]

Wow, GPA, thats some excellent technical information. Thanks a lot, but the service guy confirms that there is no leak and that he checked the system. Having read your explanation, i am sure he is given just a cursory glance and not done a detailed check.

Also is the Power Steering Pump and Power Steering Rack that you mentioned a single unit replaced together or are they separate things, because if the leak is in the rack, whats the point of replacing the pump.

Can the service centre actually find the leak and fix it or is it standard practice to just replace the unit ?

Also is it safe to continue driving the car like this, like the service guy said ?

[gpa]

Originally Posted by jinu_joseph

Wow, GPA, thats some excellent technical information. Thanks a lot, but the service guy confirms that there is no leak and that he checked the system. Having read your explanation, i am sure he is given just a cursory glance and not done a detailed check.

Also is the Power Steering Pump and Power Steering Rack that you mentioned a single unit replaced together or are they separate things, because if the leak is in the rack, whats the point of replacing the pump.

Can the service centre actually find the leak and fix it or is it standard practice to just replace the unit ?

Also is it safe to continue driving the car like this, like the service guy said ?

Yes, I reckon he has done just a casual check. If there was indeed no leak, why did the fluid level in the resevoir fall? I have a Santro with the same hydraulic PS system and in 56,000+ kms of driving, I've never had to top up the fluid apart from changing it once at 30,000 kms.

The rack and the pump are seperate units. Its the pump that's more prone to failure and so that will have to be replaced, hopefully as a last resort measure.

Depending on the nature of the problem, they can either fix the leak or will have to replace the pump (if it has been running on low fluid levels and worn)

The PS system is not something that I would take lightly and hence I would recommend that you get it checked throughly and not drive around with a problem that could spell disaster when you least expect it.

Cheers,
gpa

[jinu_joseph]

Thanks GPA will get it checked up again this weekend.
PS: why did you change PS oil at 30K. Is that a recommended practise ?

[jinu_joseph]

Folks
I have to replace the PS pump, but doing it from the Authorized service centre will cost me about 15K+, but I have heard that the local Garages can source such original parts from written off vehicles and give it to you for much lesser price, but the key here is to have a very trustworthy mechanic/workshop.

So can anybody recommend a trusted workshop where i can get this done ?

Also a related question, i have noticed that my engine noise entering the cabin has increased especially on reving the engine (3k rpm), i am not sure why. The Service centre could not find any problem except for the PS pump. Would installing a Free Flow Exhaust reduce this engine noise.

[jinu_joseph]

Waiting for your inputs