Serpentine belt is screaming at power steering pump.

[Pete]

My TB's belt has started screaming at the ps pump when the engine is running above 2,000 rpms. The pump, belt and tensioner are all new and there is plenty of fluid. The steering feels a little off at times but the belt slippage isn't effected by turning, just rpms.

Any ideas? It's been in a local shop twice and they keep telling me things are fine. The mechanic must drive junk.

Is there a pressure valve that might not be working? Bad valves in the rack? Whatever it is I've never seen it before.

 

[Pete]

My truck is a 2005 Trailblazer LT with a 4.2 and about 120,000 miles on it.

 

[Sparky]

Sounds like something is up with the pump making it stiff to spin at higher speed.

I seem to recall something about the pump needing a part switched out for proper pressure. There was a page in with the pump another member got. Do you recall seeing anything like that?

 

[Pete]

No, I haven't seen it yet but I'll keep looking.

 

[Mounce]

Maybe take the belt off and rotate the pump by hand and see if it feels funny or gritty. Maybe a bearing has went bad causing it to scream.

 

[Tiggerr]

You sure it's the pump squawking? IIRC the tensioner is right below the pump pulley. Could it be that? Can you physically see the belt slipping on that exact pulley? Possible you got a bad pump as well if that's it. It's happened to me before.

 

[Pete]

I've done all of that. The pump itself is fine.

 

[Pete]

It is slipping at the pump. The tensioner is fine as is the belt. It is acting like the flow of fluid is restricted or the pressure is too high.

 

[Sparky]

That's why I wonder about the regulation valve in there. I'll have to see if I can dig up the info.

 

[Tiggerr]

Can't be the pressure I don't think. Good way to test would be crank your wheel all the way to one side till it stops and keep pushing. See what it does. That'd be the highest pressure your going to generate in the system. Otherwise it had to be an RPM issue in the pump. Bearings or something. Idk

 

[Mooseman]

If you do that, don't rev the engine. That's how the pump shaft gets broken. Or don't turn it to full lock while revving it.

 

[Tiggerr]

If you do that, don't rev the engine. That's how the pump shaft gets broken. Or don't turn it to full lock while revving it.

Definitely just at idle. No need to rev

 

[Pete]

I've tried all of that. At idle it pretty well seems fine. Try to pull a hill at 60 mph and it screams until I let off the gas. Take it to 3000 rpm in the driveway and the belt starts slipping at the PSP. A new PSP reduced the slippage when accelerating but not enough to get happy about.

Sometimes I really miss '72 dodge darts.

 

[Texan]

Could the belt possibly be the wrong length?

 

[Pete]

No.

 

[Tiggerr]

It was doing this before you replaced the pump?
From what you just said, it sounds like this was the reason you changed it to begin with? Am I seeing this right?

 

[Pete]

Yes, it was. I replaced the belt and tensioner. Then had a pump swap done. There was no significant improvement.

 

[Tiggerr]

Ok. Then there's got to be some kind of issue in the rack or lines. Maybe a line collapsing on the inside. Why would it do that? I have no idea. Or maybe in the cooler. Idk. Maybe in that seal at the rack on the pressure line is restricting it somehow. I know they changed the design of it at some point. You said the steering didn't feel right at times.... In what way?

 

[Sparky]

Oh. Maybe something in the rack then...

 

[Pete]

The steering wheel feel isn't quite right, usually at low speed such as crossing a parking lot. First time made me wonder if the engine had stalled.

I'm starting to think that it's time to mee
t the mechanics at the dealership.

 

[Sparky]

Does it get stiff/groan when it acts weird? Mine has been doing that for a little over a year now randomly, not consistent although a few turns here and there I can always get it to replicate.

 

[Tiggerr]

If it's getting stiff spots or hard spots however you want to think of it. Times when it feels like there's no PS, When you turn the wheel. It's the rack. While your doing the rack, may as well do the lines too.

If not, next week after you fix the rack, a line will puke. lol.... That's my luck anyway.

 

[Mooseman]

Or it's quite possible that the PS pump is defective. I've had bad pumps right out of the box but mostly would whine. If you had it done at the dealer, definitely take it back.

What was the reason for the replacement pump in the first place?

 

[Pete]

I swapped the pump because that's where the belt was slipping and the pump is way cheaper than a rack. There isn't really any other noise and I was hoping the pump would do it. I have to get to Baltimore on Friday and my only other option to get there is a 4 hour ride with my ex-wife.

 

[Mooseman]

OMG! We can't let you down then! This has now become a mission!

If it was replaced for the same problem, then I'm afraid that the rack would be the source of the problem since there isn't anything else in the system, barring a kinked line.

 

[Tiggerr]

Unfortunately with the pump not solving the issue, and your other symptoms you described. Sounds like rack time. Usually a dead givaway is the hard spots when turning the wheel. Always been the rack on anything I've had do that. That's what mine was doing right before it started puking fluid.

 

[Pete]

I think that you folks are right. I could strangle the mechanic that wasted a week and gave the truck back saying there was nothing wrong.

 

[Tiggerr]

I think that you folks are right. I could strangle the mechanic that wasted a week and gave the truck back saying there was nothing wrong.

Unfortunately competence is sadly lacking in that profession. There's good ones out there. Hard to find though anymore. Least he didn't try to sell you a new crankshaft or something lol!

 

[Mooseman]

A week to replace a pump? Give me an hour and I'll replace it and flush the system too!

The rack is a different story. That would be at least half a day + an alignment.

 

[Pete]

I had it in the shop twice. Went the second time because I figured I could get him to get right on it since he didn't fix it right the first time.