Engine knock at cold startup - RX450H
Driver
Joined: Sep 2016
Posts: 189
Likes: 15
From: IL
That noise is what mechanics call dry start . It's basically starting the car while the oil has a delay on lubricating the rod bearing and it causes a slight second of piston slap. I don't understand why it does it but my Ls430 does it sometimes and other times it doesnt. I'm thinking it's the temperature outside and it also depends on your old conditions. If you start it up and it makes the knock while a engine oil light on,you have a problem .
I know this is an old thread but any update from FJ40DRM? I am at 88K with the " gear backlash noise" at start up in the morning. Fresh oil change with MobileOne Synthetic 0-20W still making noise. No CEL.
Last edited by d2gs3; Apr 20, 2017 at 10:47 AM.
No, it still make noise. Definitely something need oil. Anyone figure out what is the exact root cause? Oil pump weak? I really want to fix this. When startup cold (in morning or afternoon after work) the engine shake slightly but no CEL. It shake for about 1 to 2 minutes. Car is 2010 RX450h with 88K miles.
Last edited by d2gs3; Apr 25, 2017 at 08:17 PM.
Pit Crew
Joined: May 2016
Posts: 239
Likes: 28
From: Nv
I don't know anything about that particular engine, but if it is shaking badly on startup, I certainly would not be driving it. You need to have it looked at by a good shop that is familiar with your setup.
Lead Lap
Joined: Nov 2013
Posts: 565
Likes: 59
From: Florichigan
Basic engine diagnostics was, and is: Air, Fuel, Ignition - therefore, when diagnosing a rough-running engine, start with things that one can easily rule out.
At your car's mileage, fouled spark plugs is not impossible, and can be readily-inexpensively ruled out (by replacement), fuel issues mitigated (with fuel system cleaning), and air management checked (tailpipe emissions and electronic combustion control system analysis come to mind).
A temporarily rough-running engine at startup accompanied by noise that is caused by a mechanical issue is possible (valvetrain timing management?) however why jump into explorative heart surgery before high blood pressure and stress-reduction?
At your car's mileage, fouled spark plugs is not impossible, and can be readily-inexpensively ruled out (by replacement), fuel issues mitigated (with fuel system cleaning), and air management checked (tailpipe emissions and electronic combustion control system analysis come to mind).
A temporarily rough-running engine at startup accompanied by noise that is caused by a mechanical issue is possible (valvetrain timing management?) however why jump into explorative heart surgery before high blood pressure and stress-reduction?
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Basic engine diagnostics was, and is: Air, Fuel, Ignition - therefore, when diagnosing a rough-running engine, start with things that one can easily rule out.
At your car's mileage, fouled spark plugs is not impossible, and can be readily-inexpensively ruled out (by replacement), fuel issues mitigated (with fuel system cleaning), and air management checked (tailpipe emissions and electronic combustion control system analysis come to mind).
A temporarily rough-running engine at startup accompanied by noise that is caused by a mechanical issue is possible (valvetrain timing management?) however why jump into explorative heart surgery before high blood pressure and stress-reduction?
At your car's mileage, fouled spark plugs is not impossible, and can be readily-inexpensively ruled out (by replacement), fuel issues mitigated (with fuel system cleaning), and air management checked (tailpipe emissions and electronic combustion control system analysis come to mind).
A temporarily rough-running engine at startup accompanied by noise that is caused by a mechanical issue is possible (valvetrain timing management?) however why jump into explorative heart surgery before high blood pressure and stress-reduction?
- Foul spark plugs is possible but why after 1 minutes it run smoothly?
- While doing spark plugs, I will inspect the injectors as well.
- Seem to be not many people here wrenching the car (sad), either they rely on warranty or Lexus stealer to fix the car so not much info for DIY on any major issue
Driver
Joined: Mar 2007
Posts: 62
Likes: 19
From: NJ
I'm having a similar issue. CEL is on and took it to the stealership only to tell me there was water in the gas. I thought it was odd and told me run the car down to very minimum levels and hopefully the light will go away. Told me it's a hybrid issue.
Looking for a better solution. Thinking of getting a second opinion at another dealership.
Looking for a better solution. Thinking of getting a second opinion at another dealership.
Pole Position
Joined: Dec 2012
Posts: 2,136
Likes: 953
From: Toronto, ON
I'm having a similar issue. CEL is on and took it to the stealership only to tell me there was water in the gas. I thought it was odd and told me run the car down to very minimum levels and hopefully the light will go away. Told me it's a hybrid issue.
Looking for a better solution. Thinking of getting a second opinion at another dealership.
Looking for a better solution. Thinking of getting a second opinion at another dealership.
Driver
Joined: Mar 2007
Posts: 62
Likes: 19
From: NJ
Thanks for the insight!
Pit Crew
Joined: Oct 2017
Posts: 205
Likes: 43
From: DE
My was knocking like a **** on startup, and while sitting in traffic the car goes from hybrid to gas, the whole car gets loud bang and extreme shakes. It sounded like the car was going to blow up... my rx is lexus dealer maintain, since they fixed all the issue under warranty/extended warranty I dont really care at this point.. as I have 3 days left with my rx.. traded it for a MDX
Driver School Candidate
Joined: Dec 2018
Posts: 2
Likes: 0
From: NY
Joined this forum just to add this: consider using the Archoil 9100 oil additive. On cold startups I experienced the same problem except that it could also be felt through the seat. Had this car had a turbo like my turbo Subaru I would've been very concerned as it usually means a new shortblock. Hearing this on a Toyota made me less concerned. I already had Archoil 9100 for my Subaru so I tried it on the RX450h along with my next full synthetic change. Upon cold startups I can still hear light rattling on occasions when I really listen for it (i.e. radio off), but it is now much quieter and I haven't felt it through the seat/chassis since. I recently started the car after returning from a weeklong trip where temps at home were 30f - 40f, the startup was still smooth. Archoil is also popular among the Ford Power Stroke crowd for stiction issues, as well. Look for Jay Leno's feature on it on YouTube.
Driver School Candidate
Joined: Feb 2022
Posts: 1
Likes: 0
From: Abu Dhabi
Lexus ES 350 Cold Start all the time
[QUOTE=lexusls4;9717120]
What is the best solution to every time starting the cold Start happens even after running and switch off within 5mins it will make sound…
Someone said injectors ? If it knocks really hard, its the TSB, happened to me a 79k and again at 115k.. I'm at 126k now. Luckily I had extended warranty, cost a bundle if its was out...
https://www.clublexus.com/forums/hyb...anty-work.html - Check out the photos on the injector here...
https://www.clublexus.com/forums/hyb...t-came-on.html
TSB L-SB-0045-12 - Replaced 6 fuel injectors
23209-31160
23291-28020 - insulators
25627-31030 - EGR gasket
17179-31010 - Intake manif gasket
17176-0P021 - Air Surge gasket[/QUOTE. If the noise is a slight tap ,then it could be injector. I still highly doubt it . If it's making the noise for a few second then you might have to check your oil weight and condition of it. If that noise goes on every time you start the car ,and imagine if you start the car ten times a day. This will usually cause premature wear on the rod bearing no question ask . I been a mechanic for 20 years working on Hondas ,and I know their variable valve timing engine are known for dry start . I would be concern if I had less then 100k miles ,then again it shouldn't do this even at 200k miles .
https://www.clublexus.com/forums/hyb...anty-work.html - Check out the photos on the injector here...
https://www.clublexus.com/forums/hyb...t-came-on.html
TSB L-SB-0045-12 - Replaced 6 fuel injectors
23209-31160
23291-28020 - insulators
25627-31030 - EGR gasket
17179-31010 - Intake manif gasket
17176-0P021 - Air Surge gasket[/QUOTE. If the noise is a slight tap ,then it could be injector. I still highly doubt it . If it's making the noise for a few second then you might have to check your oil weight and condition of it. If that noise goes on every time you start the car ,and imagine if you start the car ten times a day. This will usually cause premature wear on the rod bearing no question ask . I been a mechanic for 20 years working on Hondas ,and I know their variable valve timing engine are known for dry start . I would be concern if I had less then 100k miles ,then again it shouldn't do this even at 200k miles .
