power steering pump whine issues

Schurkey said:

There may be a difference in output pressure or volume...but I don't think so. Far as I know, it's one vs. two return nipples.

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Caman96 said:

IDK, but just looking there are pumps that specific to Hydroboost. When replacing, which one do you use?

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kylenautique said:

Alright... I'm getting pretty frustrated with this. Every single new pump I buy whines. Currently, it goes away after it warms up, but its annoying for sure. I originally replaced my original pump with an O'Reilly master pro pump. It was quiet, but only lasted about a year and started to loose power. I replaced it under warranty, and the same thing happened about a year later. When I rebuilt my engine, they warrantied it out with a Cardone pump. Holy crap that sucker whined like it was about to go into orbit! They warrantied it for me... same issue. Finally, I decided to put an AC Delco pump on it... It was pretty noisy, so again, we warrantied it. My current AC Delco pump whines when its cold, and it goes away. Is this something I need to just accept? Should I replace it and try a Napa brand pump? The original pump lasted 200,000 miles..

My 98 K1500 has been converted to hydroboost, and I'm using currently using power steering fluid, not ATF. The last AC Delco pump, I tried both fluids. They didn't make a difference. I went with GM rated power steering fluid with this current pump.

And yes, I know how to properly bleed the steering system Anyone else having issues with replacement power steering pumps?

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Schurkey said:

The one for vacuum boosters has a single return nipple, 'cause only the steering gear uses PS fluid.

The one for vehicles with Hydroboost has two return nipples, 'cause both the Hydroboost and the steering gear are returning fluid to the pump.

There may be a difference in output pressure or volume...but I don't think so. Far as I know, it's one vs. two return nipples.

Click to expand...

Schurkey said:

The one for vacuum boosters has a single return nipple, 'cause only the steering gear uses PS fluid.

The one for vehicles with Hydroboost has two return nipples, 'cause both the Hydroboost and the steering gear are returning fluid to the pump.

There may be a difference in output pressure or volume...but I don't think so. Far as I know, it's one vs. two return nipples.

Click to expand...

RShrimp said:

When I worked at GM dealers in the late 70's and 80's we used to add a little EOS to the steering pump and it would quiet them right down. GM EOS is about the same thing as STP ( Engine Oil Supplement)

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