Engine squeal when power steering engages

I've had several people look at this and a garge had the car for 3 days and couldn't figure out what the noise is or where it's coming from. It happens when the engine has warmed up some and the steering wheel is turned enough for the power steering to engage, most noticable when parking or stationary and turning the wheel slightly.

A scope has been on every pulley, the belt has been changed 3 times, idle pulley replaced, tensioner adjusted. The vacuum hoses have been replaced and are all clear, the PCV valve on the power steering pump has been changed for new, power steering fluid flushed and replaced. It seems to be coming from behind the driverside cam cover when listening, but the scope says no.

I wondered if anyone has come accross something like this before and has an idea what next to look into. I've been advised to run the car as normal and see what changes if at all. I changed the engine and transmission oil prior to noticing this sound happening. Doesn't affect the function of anything, no codes from the OBDII scanner. Engine is a Lexus 1UZ VVTi.

Its easy to check the belts with a quick spray of WD40. If the noise persists then I'd suspect that you either have a bad pump but that would usually then start to leak fluid or air trapped in the system. You could check to see if there are any bubbles in the reservoir or any gurgling noises when you turn lock to lock with the front jacked up.

That does sound like the actual pump to me as it sounds a mechanical noise ( metal on metal vs metal on belt ) . but still always hard to tell on a video.

what you can do is get a long screw driver and touch it on possible suspects ie the pump housing and the put the but of the driver to your ear and then get someone to bring on the fault and listen you will soon narrow down where the noise is coming from.

I had this, or something similar a few years back. It turned out to be one of the belt (power steering) wheels that has a bearing in the middle which was seizing. My mechanic mate was able to remove it and push out the old bearing and put a new bearing in, it only cost a few quid. Sorry it's not a very descriptive reply but it was some time ago and I'm not overly mechanically minded but I'm sure you know what I'm on about. Might be worth a look. He spotted it straight away.

The scope has been on everything including the pump as that was the prime suspect listening for where the source of the noise could be. The power steering fluid is still good with no contamination, I'll try full locking it whilst the wheels are off the ground to see if it still does it. Strange how the squeal comes on only when the engine has warmed up some and not from cold.

I'd hope it is something simple like a pulley bearing.

Is the crank pulley OK? Sounds very similar to a failed pulley

Marked the crank pulley with a line and it hasn’t shifted at all. I have a new crank pulley in reserve if needed.

This problem has been found and fixed for a while now and I just remembered to update this thread in case anyone else comes across a similar thing.

The vacuum hose routing was not correct. It going from the crankcase to the PCV, then PCV back to the intake manifold.

What it should be and is now doing. Venting at the crankcase, vacuum hose from PCV to intake manifold as before, PCV to the intake pipe.

No more squealing like a pig when turning with any resistance