3.4L Power Steering Pump Whining Excessively - Page 3 - Toyota 4Runner Forum

Bad Luck · 11-15-2023, 06:14 PM

Quote:

Originally Posted by bob919

Swore my whine was the PS pump going bad. Drove it for 4 years that way and finally decided to fix it.

Did all the things mentioned in this thread staring with the cheapest fix first: 1. flush/change the fluid and cleaned the screen in the reservoir; 2. rebuilt PS pump using the Gates rebuild kit; 3. replaced AC idler pulley; and finally 4. purchased a remanufactured PS from RockAuto. None of the "fixes" solved the problem. Whine was still there.

Finally took advice from an old mechanic friend of mine long gone: used long screwdriver and put it on the alternator and other end to my ear and sure enough, could hear it whining and "grinding". Bearings were bad.

Installed Denso remanufactured from RockAuto and whine is gone! Changed out all 3 belts while at it. Swear truck runs better now than it has in years.

So don't rule out the alternator bearings as the issue.

Another example why diagnosing the problem before throwing parts at it is important.

mtbtim · 11-15-2023, 08:20 PM

Quote:

Originally Posted by Bad Luck

Another example why diagnosing the problem before throwing parts at it is important.

Also another example that guys should invest in a mechanic's stethoscope. The screwdriver trick works, but I like the stethoscope better. I had a pulley noise I had to deal with not too long ago and I was quickly able to diagnose it was the alternator pulley bearing with my stethoscope. This is a tool every DIY Mechanic should own.

Here's the one I own:
Amazon.com

bob919 · 11-21-2023, 04:57 PM

For the record, my mechanic had said he thought the whine was coming from the PS pump after I got some other work done on it so that's why I focused on it.

I was also trying to go from the cheapest fix to the most expensive fix.
Looking back, I would not have spent my time and effort flushing and then rebuilding my old PS pump - I would have flushed and put a remanufactured pump on in one swoop. Tim's great video of flushing and cleaning the screens solved his problem so I thought I would see if I could get out that easily (and cheap) also.

Even though it wasn't the problem, replacing my old one with the remanufactured one (and a flush) did result in better handling as it seems the steering is more responsive. IMHO.

But I understand if someone wants to rebuild their own. That's their choice.

So that's why I posted, so others could learn from my mistake(s).....and my mechanic's original misdiagnosis.

mtbtim · 11-21-2023, 05:06 PM

Quote:

Originally Posted by bob919

For the record, my mechanic had said he thought the whine was coming from the PS pump after I got some other work done on it.

So that's why I posted, so others could learn from my mistake(s).....and his misdiagnosis.

Sounds like your "Mechanic" should invest in a mechanic's stethoscope as well.