Loud power steering plus milky fluid

Couldn't find much on a search so pardon if this is redundant. On my 2000 V6 PreRunner, the power steering whine is pretty bad and makes noise even when front wheels are straight. I looked in on the fluid and it looks a bit milky but reasonably full. Air leak? Water leak? Would a flush cure this?

 

Suck out the fluid and see if your filter screen is plugged. If so remove the reservoir and clean out with brake cleaner. Flush the system a few times after you reinstall. Make sure you are using ATF, not PS fluid.

 

Most often Milky is Moisture.

A bad cap will suck moisture

 

Thanks for the suggestions. Will do both a flush, and possibly replace cap. Either way it will eliminate some possible reasons. Way less $$ than a pump and who knows what else.

 

'Milky' appearance coupled with noise could be frothed fluid- which will seem fuller thn it really is and cause the noise. check the level when the truck is off, after sitting for an hour or so. Also check for wetness on the hoses- I've had a pin-hole on the hose between the reservior and the pump do the same thing: the pump was drawing air in through the pinhole and cavitating/frothing the fluid. It only leaked when the vehicle was turned off, and not even enough to drip.

 

To paetersen: I went out and checked again when it was totally cold, and although the level still was in the right range, I notice what looks like micro spray droplets on the belt that runs the pump. Yet could not find any other leak evidence anywhere, neither garage floor nor related components. Really mysterious. I'll start by checking the hose you mention and looking again with better light, too. Thanks

 

When it was cold, was the fluid the right color in the reservoir?

If it's only milky when running it's probably an air leak. Easy to test because when you turn it off and look in the reservoir you'll see the bubbles rising/popping on the surface.

Most common leaks are the soft hose segments on the return line. On the 2.7L there is one connecting the inlet barb on the reservoir to the hard line, just below the battery tray, and another stretch that connects the rack to the hard line, down on the inside of the driver side frame, above the lower control arm. Not Sure what the V6 return line looks like.

Like another user mentioned, there might not even be a hole big enough to leak fluid. When the pump is running, the return line can suck air in at these pinholes, and froth. It makes a god awful sound.

 

@Tacoscar-the-grouch: When it's cold the fluid is brown and still kind of muddy or milky. Going to try to trace that god awful sound, it occurs when the wheels are straight too. Still could be what you're talking about.

 

Good luck.

If the fluid is brown and gross a flush is in order for sure, regardless of other issues. I would install an inline magnetic filter on the return line as well, while you're in there.

 

A good flush and cleaning the screen are definitely the right place to start, but if you end up needing a new pump don't get a new one, rebuild the one you have. It's pretty easy to rebuild.

Get this rebuild kit: https://www.toyotapartsdeal.com/oem...ion=vane-pump-reservoir-power-steering,,04446

This thread, https://www.tacomaworld.com/threads/power-steering-pump-rebuild-how-to-with-photos.377002/ will show you how to do it. That thread is for a 4-cylinder pump, but it will show you enough to get it done. The 6-cylinder pump is actually easier because it doesn't have a bearing.

But definitely do the flush, screen cleaning, and checking for leaky hoses first.

 

The milky fluid when combined with the whine from the pump indicates it is sucking air and the fluid is aerated. That causes the pump to cavitate causing the noise you hear. I'd start with a very through cleaning of the pump, reservoir, and hoses. Then attempt to pinpoint the leak. Since it's sucking air more than its spitting fluid I'd suspect the leak is on the low pressure side of the system.

 

The seals in the pump are probably bad and that is where the system is sucking in air from hence why the fluid is aerated and full of super tiny bubbles.

He should rebuild or replace the pump including cleaning the screen and go from there.

 

Three years and 15,000 miles ago I flushed out my P.S. with P.S. fluid rather than ATF........( again I did it with P.S. fluid a year later ) everything is still performing excellent.

DID I MAKE A MAJOR MISTAKE ?????

Thanks.

 

You made a mistake. To my knowledge at least, all first gen's call for ATF in the PS system. However, 3 years and 15,000 miles and everything looks good? I guess it was not a MAJOR mistake, or something would have imploded by now.

My understanding is that the different fluids have different effects on the seals in the system. In other words, PS fluid may break down seals in the system faster than ATF. I do not know what would happen at this point if you went back to ATF. I am sure other members here have experience or stories of folks putting PS fluid in that might be of use to you.

 

Thanks for the reply.......I don’t want to hijack this thread. Sorry about that. I see now there is plenty on the internet about this subject and PS fluid seems to be okay so I’ll just let it ride.

 

UPDATE: I noticed, after running the engine a short time, there were micro bubbles in the reservoir, just like you had said could be. One of the thread posts had said that the cap could be suspect, I wound tape around the whole top part of the reservoir, both the cap and the top tin lid where it joins. Bingo, no more noise and problem, so here's the question: Could it be that's where the air had been coming in, and possibly why I simply cannot see evidence of leaking anywhere? And is it more likely the actual top cap or the upper tin lid of the reservoir? Pardon the questions, but I'm sure you know how good it feels to at least temporarily fix something like this with tape! Cheers.

 

Hmm. Well I don't think the cap matters (the part that screws on with the dip stick) because you can run it with no cap and no problems on a well functioning pump. Not that you don't need a lid at all, but you should be able to remove it to check the level while running with no problem.

Same with the tin lid - assuming you mean the top of the reservoir where it joins with the cylindrical portion of the reservoir. I am skeptical that an air leak there would matter, since it should not be submerged in fluid anyway.

My theory is that you wiggled the reservoir enough to move the O-ring at the bottom, which is another possible site for air leak. Or maybe re-seated the return line just enough.

At the end of the day, if tape fixed it, all good. If it comes back in the future then you'll have more trouble shooting.

 

@Tacoscar-the-grouch Thanks for that info, immensely valuable. If I can get to where I can see the bottom of the reservoir, would I see the O-ring while the reservoir is still in place? At least it's looking less like an actual pump replacement and more a clever leak detection and proper leak fix.

 

No, you must remove the reservoir from the pump to see the O-ring.

If you go ahead with a fluid flush and reservoir screen cleaning, then you will need to remove the reservoir and should replace the O-ring at the same time.

If you still have the factory 20 year old return line, then I would replace that as well and add an inline filter as well. It might be old and dry enough that it won't seal up again well. PS hose is cheap, and the filters are like $20 bucks.

The cheapest and easiest fluid flush is to suction as much fluid out of the reservoir as possible, fill it with fresh, turn wheel lock to lock 3-4 times to move fluid through, and repeat. Eventually you will have removed and replaced most of the old fluid.

 

@Tacoscar-the-grouch Super. I’ll order an O-ring and hose, do a flush, screen clean and consider it overdue maintenance. The tape is temporary at best. Final $64000 question: can I take off that reservoir without touching the belt nor removing pump? I’ll get on it when I get a seal and some ATF