North

Hello I have a 2013 RX 450h, I have noticed in the morning especially when car is cold, the engine makes a whirring or buzzing type noise to begin with but once warm I no longer hear it. I would appreciate any others who have an RX 450h let me know if they have noticed this sound. Thanks

tempestv8

What duration does this buzzing/whirring noise last for? It might well be the brake accumulator. See red arrow of this device, which is normally hidden behind the plastic shrouding.

You might want to take it off and get someone to pump the foot brake a few times with ignition off, before turning on the ignition whilst you are listening at this device.

salimshah

Mine always keeps making noise. Some whirs and chirps, almost like a pet who keeps reminding me that its alive.

Salim

North

It only does it when warming up, it's a steady buzzing that goes away when warm. Perhaps its normal???? Thanks guys!!

ukrkoz

brake system is priming, building up pressure, at start up. NORMALLY it should last only about 5-10 seconds though. Also, it should buzz AFTER shut down, a bit later after system was turned off. If you stay in garage for a little bit, you'll hear that buzz come up and whirr. Again, it is a short term buzz only. Anything that lasts long time or keeps cming on and off points towards potential coming issue with brake accumulator (or actuator? One of the two) that were known to go bad. We had a bunch of those issues at Camry Hybrid forum.

ukrkoz

I am curious. Why does that bar look spray painted?

North

You are exactly right, it turns into a noise that sounds like a power steering wheel pump that's low on fluid, that's the only think I can compare it to. However it last probably about say 10 minutes at the most. Its a CPO at the Lexus dealership now being checked out, for a different problem that we noticed last week on morning when we cranked it up it sputtered, idled rough kinda clanked and jumped around then smoothed out, I just hope I haven't traded my RX 350 that I never had a minutes problem with for a lemon. It worries me! I will call the Lexus guys and have them check the brake actuator too! Thanks!!!! Tim

tempestv8

Not sure why. It's just a photo that I found on the internet using Google. I suspect if you take your plastic covers off, you'll see similar paint artifacts like that. This is of my own vehicle:



Same sort of "spray painted" look, hiding underneath all that shrouding.

Hi Tim,

I'm a bit worried about this as there have been a number of posts on the Hybrid forum about the engine spluttering and idling rough post cold startup. I suspect this may be due to the injectors getting clogged up with gunk from the exhaust system - the miller cycle engine in the RX450h (2gr-fxe) has an EGR system, which I don't think the otto cycle on the regular RX350 (2gr-fe) has. It wouldn't surprise me that soot is being introduced back into the inlet manifold along with the exhaust gases.

So I'm now running premium fuel (95 octane) with my engine, just in the hope that it will be less "sooty" but since EGR is being introduced into the inlet manifold under certain conditions controlled by the ECU, I suspect that long term, this EGR system will be detrimental to the health of the engine, particularly the fuel injectors. See this thread: https://www.clublexus.com/forums/hyb...anty-work.html

Back to your original concern re the buzzing, I don't hear this buzzing which you've described as occurring with about 10 minutes duration. Probably wise to get it checked out by your Lexus service center, especially if it's the braking system that might be the source of the buzzing noise.

ukrkoz

Very interesting. None of this on my Highlander Hybrid - "spray paint" effect - though it's same power train. And, pretty much same structure underneath the covers. Mine is uniform black. Thank you for clarification.

North

Hello again, I know this has been covered several times but I would like your guys opinion on something. I have a RX 450 h 2013 model. I have the extended warranty. I bought it back in January, it has 70,000 miles on it. Now that cold weather has come back I STILL have the engine knock when 1st starting. It only lasts for approximately maybe 20 seconds, but it is a definite knock/ clanking, sounds light metal hitting metal. I know this cannot be normal. I have had it to the dealership and of course they cannot find anything wrong. I plan on making a video of it with my phone and taking it back in. I want this fixed before the warranty runs out. Its as smooth as silk when it warms up but almost sounds like almost sounds like a diesel engine when cold. I have had 2 Priuses and NEVER had this problem. Please HELP!!!

ukrkoz

You will have much better success with dedicated thread.

It's timing chain slap. Timing chains do stretch AND hydraulic tensioner in it is fed by oil pressure. Now, "when it turns cold", oil is more viscous and takes some time to build up proper pressure. Also, tensioner oil passage may be simply clogged... Both combined will result in poor initial tensioner action, resulting in stretched chain slap. That it is stretched, is guaranteed, as they do show signs of stretch after about 40 000 miles. Then it's up to tensioner to take that slack out.
Your engine does not have hydraulic lifters. Toyota does not do them, it does tappets. So can't blame it on rockers noise.

Droid13

Research "piston slap" and see if the sounds are similar to your own experience. Piston slap is commonly associated with a metal on metal knock in a cold engine, especially with aluminum engine blocks and pistons, and also with pistons that have short skirts which both are the case for this engine type. Manufacturers like aluminum pistons with short skirts because they are much lighter and perform better/improves engine response (great for an object that moves very quickly but must reverse direction thousands of times every minute), but this noise is a downside sometimes occurring.

The knock noise in an engine experiencing piston slap is due to a rocking motion in the piston as it reverses direction in the engine, causing the side of the piston to hit the cylinder wall. Aluminum expands a lot more than steel due to heating, and pistons typically get hotter than engine block as the block has more cooling than the piston. This means that some notable amount of play must exist for a piston inside a cylinder block when cold to allow for this expansion, otherwise it would seize. So in a cold engine, the pistons have more room to move within a cylinder, and pistons with short skirts are also more likely to move within a cylinder.

After the pistons heat up and have expanded to fit snugly within the cylinder, this rocking motion decreases and the noise goes away. "Light" piston slap is not generally considered a defect and does not affect reliability, especially if it completely goes away within a minute or so. Trying to eliminate the noise might require a new engine or a rebuild and hope the new engine has a bit tighter tolerances, at least initially. It would be hard to get a new engine under warranty if this describes your issue, and the dealer will no doubt throw out the "normal" comment because it can be, but not necessarily affecting all engines or all engines to the same degree.

Of course, there are other reasons an engine might knock when cold, oil flow issues, sensor issues, fuel injector issues, fuel issues, etc. Just something to ponder.

North

I know this has been covered a few times but I'm at my wits end trying to get the dealership to address this issue. I have a 2013 RX450h that has 71,000 miles on it. I purchased it last January (2018) and it is a CPO. Since I have owned it I have had MANY instances that when it starts from as they call it COLD SOAK, (starting up during cold weather after the car has sat for a while) it knocks for about 45 seconds. It sounds just like a knock from the pistons, lifters, I really am unsure. The sound is like someone using a small hammer tapping on the top of the engine. When I first noticed it about 2 weeks after I purchased the car, the engine jumped around and misfired like it was going to go dead. I've had no more instances like that but still it knocks when starting up in cold weather. I have gone round and round with the dealership and they said that could not duplicate the noise. I feel like they know that this is a problem as I have read about this several times on the net. I want them to fix this problem while its under warranty but cannot get anywhere with them. I really would like to keep this car it's beautiful and I love driving it, but don't want the engine to fail prematurely one day because something was not addressed early on. Please any advise would be GREATLY appreciated. I haven't give up on the dealership by the way. Should I notify Lexus with this problem and see where I get with them? I got the review from my experience from the dealer from Lexus should I give them a bad review ? Thanks so much!!!

North

Thanks so much, sorry didn't see this before I just posted about this again.

North

Thanks Andy, sorry didn't see your reply, before I posted about this again, I will continue to address this will the dealer before the warranty runs out, I did in fact take a video of the noise and they wanted it but still said they could get the car to reproduce the noise. I just don't want the engine to fail prematurely! Thanks again!!!