Hope they completed the full and UPDATED TSB - the vacuum pump is replace which was the initial TSB but later an updated TSB issued which replaced the vacuum pump AND the part it connects to.
I can't tell you the part name but the original one has a round port the pump connects to, the updated part has the port with an extra section shaved out of the round port. This than stops the oil slapping around when cold.

 

If it was the vacuum pump the sound will change when you put it into drive and back to park. The engine speed changes which changes the sound.

If it was the ABS that could well be true. These cars do make a few strange sounds at start up and after shut down, if it's only minor and goes away after a few seconds I wouldn't worry about it.

Some people are more sensitive to noises than others, my wife would struggle to hear any odd sounds whereas I hear everthing. Also if you are in a very quiet area you may hear things others don't when there's more ambient noise around.

 

What does the vacuum pump issue sound like?

It just seems strange to me that an ABS self check would make that kind of noise.
But it's been consistent that I only hear it when driving off after initial start-up, and it's always just the single knock, that I've just accepted it.

 

Is it just a single knock, and always only after startup?
How loud is "crazy loud"?

If it's a single knock, I'm not certain it has anything to do with the vacuum pump, because wouldn't that noise be more persistent?

Does it sound like the attached recording in post #8 of this thread?

 

The vacuum pump noise is a constant knocking for around a minute or two.
When I reverse out of my garage I always hear this one knock sound, thought it was the suspension moving but maybe it's the ABS. Only notice it in the garage but that could be the noise reflecting off the garage walls.

 

What you are talking about is the port that connects the pump but in 2016 or 2017 Lexus changed this at manufacturing so anything newer has the updated port. This is what Lexus and the dealership lead tech told me.

Just to repost, this is the noise I am talking about on my car, are your cars like this? Listen to at least the 30 second mark to really hear it

 

First post! Registered specifically to report this same engine rattling nose issue on cold starts on a new-to-me 2017 rx. Had the dealer check it out (kept vehicle overnight) and they say they can't hear it... Not sure how, as it is VERY obvious, identical to above posted video.

A family member has a 2018 that does not have the noise. I might try a different dealer to see if they will at least replace vacuum pump (I wouldn't want to go through the whole engine out procedure mentioned earlier in the thread). I'd be happy even if noise reduces by 50%, as long as the noise does not cause any long term mechanical issues.

 

They cant replicate it because they arent doing it right. For them to not notice the noise is just them deflecting here. My service department and lead tech and all of lexus have said that this happens on almost all 3.5 motors.

I took mine to my dealership and they couldnt hear the noise. I took it back and showed them my video and gave specific instructions on how to replicate:
cold start so let it sit overnight
need 2 people
one has to be in the car, start it, and move in gear (not step on gas) just coast forward for 2' then stop.
another outside with the hood up
the noise ramps up in gear when its moving, then when you stop it settles down, so move again and it will ramp up.

They heard it. They replaced the vacuum pump and it sill did it. They replaced it with another and it still did it. So my car still does it. They dont think its acceptable but they dont have a solution. I am working with lexus on this now. They suggest another dealership so I am going to talk with them but I already sent video and they made a case, no solution though. I am still taking it to document that I did though.

All techs and lexus has stated its just a noise, not mechanical so that makes me feel better.

 

Thanks for the reply and instructions! Not sure if it's even worth pursuing, as replacing the vacuum pump alone doesn't make a difference. It's reassuring to hear that it won't cause any mechanical issues long term though. I'll still talk to the dealer again about it, but for now my solution is remote start the car for a few minutes (which I have to do in this freezing Canadian weather anyways) and that significantly reduces the noise once I put it in gear and drive off.

 

Yes it's not hurting the engine, just cold oil slapping around creating that knocking noise.

 

Personally, as long as the noise isn't super annoying, and most importantly, does not indicate any kind of mechanical issue now or in the future, I'll just live with it.

Not sure it's the mentality one should have or expect to have when getting a new Lexus, but it seems like that's reality.

 

hey all,

I just got a '17 RX 350 and my car was also had the same exact noise as shown the videos above. The car is still under warranty so I had them look in to it.

The dealer replaced the vacuum pump and I can say that ITS GONE. The told me the pump was "redesigned" to address the issue.

my 2 cents..

 

Is it possible to post the part number for the redesigned vacuum pump? I am gonna DIY this fix.

 

This fix is not just a redesigned vacuum pump, the port that connects the vacuum pump to the engine is what has been changed.

I believe they replace the vacuum pump AND the part it attaches to, sorry I don't know what it's called but it surrounds the top of the motor and valves. The port originally is a circle which creates a knocking noise from the oil as it swishes around when cold. The redesigned port has a notch cut out which is enough to stop the noise from the oil (mostly stops it, mine still makes it very slightly, only when cold).

I don't know your experience obviously but it is a massive job, the whole engine is dropped after disconnecting suspension, drivetrain and exhaust, they than remove probably the top half of the engine, the valves, the chain driving them and all the auxiliary parts to get to the redesigned port section. Sorry I don't have the part numbers.

 

part no: 29300-0P030

see screenshot for more details