Power Steering Riddle

[NGAneer]

So guys, I had a power steering leak that I was chasing which caused me to change out my power steering pump and all hoses. Good news is, the leak is gone... But only in one direction apparently.

The pump is louder than I'd like it but it was a reman and I wasn't surprised when out of the box it was fairly noisy. Oh well, it works.

Fast forward a couple months and it seems like air is getting into the system without fluid getting out. Most notably, after my normal interstate drive to work (~15 miles) I'm greeted with an excruciating whine as if the pump is full of air. Again, no fluid leaks out. If i drive around town, the air seems to work it's way out and the pump goes back to less noisy. At times when the truck is parked, and then I start it after a little while the whine will be greater than normal.

Anyway, I'm going to end up replacing it again but I don't want to just ruin another pump because of a leak that I've missed elsewhere.

Anyone dealt with this before?

BTW, 07 Yukon, 5.3 w/ PS cooler. New lines and seals on those lines, new tentioners and idlers. When I say new, I mean less that 3 months or so.

 

[Big Mama]

Did you bleed the New one with far left and right turns? How about the ps cooler? Did it let you put in the recommended amount?

 

[NGAneer]

Did you bleed the New one with far left and right turns? How about the ps cooler? Did it let you put in the recommended amount?

Yes, did the left/right method and the vacuum method. Don't rememer the amount. Just kept bleeding it and adding until it made the fill line.

The vacuum bleed held 15 inHg over night so when cold, the system is sealed up as best I can tell.

 

[Big Mama]

Makes sense and used the correct fluid not atf?Everywhere I can think of air getting in would cause a leak except the lid. Is the fluid level dropping? I keep coming back to the pump and noise let me tag in some more experience @swathdiver @kbuskill

 

[kbuskill]

I would maybe try the vacuum test while it is up to temperature just to see if it makes a difference.

But in all honesty it sounds, to me, like you just got a bad reman.

 

[HiHoeSilver]

I think I agree here, too. I'm looking at that pump.

 

[swathdiver]

The pump is ...a reman

I'm greeted with an excruciating whine as if the pump is full of air.

Anyone dealt with this before?

Yeah, my whole driving life! LOL You can turn the radio up louder until it dies or replace it with new. I've never ever never had a reman worth a can of beans. I let the one in my '93 Olds whine away for ten years!

Always replace the pump with brand new GM/ACDelco unless you know who makes it for them.

Oh, If it's making noise after install and bleeding, it's the pump or rack. Since the rack is quiet and the pump is not, replace the pump.

Ohh! Make sure the hoses to the rack are not on backwards! GM dealer did this to one of my Montanas once and it caused the whine and they had to replace the pump because of that mistake.

 

[NGAneer]

Yeah, my whole driving life! LOL You can turn the radio up louder until it dies or replace it with new. I've never ever never had a reman worth a can of beans. I let the one in my '93 Olds whine away for ten years!

Always replace the pump with brand new GM/ACDelco unless you know who makes it for them.

Oh, If it's making noise after install and bleeding, it's the pump or rack. Since the rack is quiet and the pump is not, replace the pump.

Ohh! Make sure the hoses to the rack are not on backwards! GM dealer did this to one of my Montanas once and it caused the whine and they had to replace the pump because of that mistake.

I'd thought about the backwards hoses but it's impossible. The hold down bolt for the plate that holds them in is offset and attached to one of the hoses. It wouldn't line up otherwise. Good thought though, I had to check to be sure.

Probably just gonna get a new ACDelco pump eventually. Just sounds kinda stupid to have that whine and no actual blower.

 

[NGAneer]

Update on the vacuum reading.

Last night when I got home. I put the mityvac on the PS reservoir and pulled 15 inHg with everything still warm. I'd done this before and saw the vacuum go up as it cooled down, this time, it dropped to 14 inHg by 11pm. I pumped back to 15 inHg and it held over night. Cranked it up right after removing the vacuum and it's back to it's normal "whiney but not like a 8-71 whiney" self.

I guess clearances are opening up when it's hot and allowing air in, or at least that's what I'm left with.

 

[Big Mama]

Kinda confirms s not so good reman

 

[Derick]

I'll ask a dumb question. Have you re-greased your intermediate steering shaft?

I ask because when I got my suburban I SWORE I had a bad PS pump. Turned out it was the intermediate shaft. Jam the grease gun up there, fill it up, and then pull off the rubber boot at the firewall and grease that up too. Mine was like new in no time. Seems like a simple easy thing to check, because mine was bone dry.

 

[thompsoj22]

the pump is submerged and in no way "pulls/siphons" fluid from the system. If there is air it would likely be caused by a "vortex" in the fluid resevoir allowing the pump to ingest air. have someone in the parked vehicle and simulate freeway rpm while you watch the fluid in the pwr steering tank circulate. is the fluid swirling or relatively calm as it should be, is the fluid aerated? bubbles on the dip stick?. i think your correct with just a bad pump. a slow/obstructed/kinked return line would also allow the pump to cavitate at higher rpm.

 

[SnowDrifter]

Rather than speculating if air is in the system: Visually check if after you're done driving. While you're there, humor me and check fluid level once more.

Low fluid will introduce air into the system. And, I know this is counter intuitive, so bear with me: So will too much fluid. Couldn't tell you why or how, only that it can and does happen.

 

[NGAneer]

First off, thanks for the help guys. Answers below.

I'll ask a dumb question. Have you re-greased your intermediate steering shaft?

I ask because when I got my suburban I SWORE I had a bad PS pump. Turned out it was the intermediate shaft. Jam the grease gun up there, fill it up, and then pull off the rubber boot at the firewall and grease that up too. Mine was like new in no time. Seems like a simple easy thing to check, because mine was bone dry.

Did not think of this. I'll have to say that the noise is definitely in the pump. Mechanics stethoscope got me there. The noise also changes tone with engine RPM. Good thought though.

the pump is submerged and in no way "pulls/siphons" fluid from the system. If there is air it would likely be caused by a "vortex" in the fluid resevoir allowing the pump to ingest air. have someone in the parked vehicle and simulate freeway rpm while you watch the fluid in the pwr steering tank circulate. is the fluid swirling or relatively calm as it should be, is the fluid aerated? bubbles on the dip stick?. i think your correct with just a bad pump. a slow/obstructed/kinked return line would also allow the pump to cavitate at higher rpm.

I did think of this. I don't see a lot of bubbles and I don't see a vortex at the ~1500 rpm at which I tested it. I might try a larger RPM range to see if one may be worse than others.

Rather than speculating if air is in the system: Visually check if after you're done driving. While you're there, humor me and check fluid level once more.

Low fluid will introduce air into the system. And, I know this is counter intuitive, so bear with me: So will too much fluid. Couldn't tell you why or how, only that it can and does happen.

Fluid level is absolutely not the problem. I only say that because it was the first thing I did before changing any parts and have done consistently since.

 

[exp500]

Three questions, what power steering fluid or ATF? Is return hose higher than pump anywhere? Can you hear the relief valve Pop when you turn wheels to the stops? 1) foamy oil, 2)sucking air at retun line. 3) relief valve stuck open. Hope this helps.