Engine knock at cold startup
Thread Starter
Rookie
Joined: Aug 2014
Posts: 63
Likes: 4
From: CA
Engine knock at cold startup
There is definitely a wealth of information on this forum and it most certainly has help me with my purchase decision, thanks to all! I recently bought a 2011 460 L, CPO with 28,350 miles. Cooperate Lease vehicle. I love the looks and how it drives, smooth! But I do have a concern. Before I go to the dealer I thought I would educate myself from the experienced LS owners. I am hearing a very brief (1-2 seconds) mild engine knock at a cold startup. This only occurs when the engine is cold and has sat overnight. It never happens after this first startup, even after turning the engine off and then on again. It kinda sounds like the oil isn't getting where it should be for a few seconds. Engine sounds great with normal and hard acceleration throughout the day. The dealership where I bought it is 300 miles away, so I would be taking it to a local dealership. Now I did hear this noise and mentioned it to the service manager when I first bought the car, and the service manager told me that this cold startup sound is normal. He also mentioned the direct injectors at idle. I guess sometimes it's hard to fully trust what dealerships say. Is he right? Any ideas?
Lexus Champion
Joined: May 2010
Posts: 1,817
Likes: 89
From: Orlando STRONG!!
3 things....
1st WELCOME to CL....
2nd take it to the dealer an have them check it out.... so at worst case if serious trouble happens later you now have an "unresolved issue" logged in their system.
3rd I always put Zmax engine and fuel treatment in my cars its designed for just such things... it "soaks" into the metal to reduce engine wear (on start up or low oil situations) the fuel treatment cleans the injectors and increase fuel economy.. so its a win, win...
But because the Ls takes soooo much oil I put 2 engine treatments an 1 fuel treatment every other oil change (or once a yr depending on how much it gets driven) And I always add a fuel treatment b4 long rd trips...
1st WELCOME to CL....
2nd take it to the dealer an have them check it out.... so at worst case if serious trouble happens later you now have an "unresolved issue" logged in their system.
3rd I always put Zmax engine and fuel treatment in my cars its designed for just such things... it "soaks" into the metal to reduce engine wear (on start up or low oil situations) the fuel treatment cleans the injectors and increase fuel economy.. so its a win, win...
But because the Ls takes soooo much oil I put 2 engine treatments an 1 fuel treatment every other oil change (or once a yr depending on how much it gets driven) And I always add a fuel treatment b4 long rd trips...
Lexus Champion
Joined: May 2010
Posts: 1,817
Likes: 89
From: Orlando STRONG!!
Fyi what sold me on Zmax was about 15+ yrs ago I bought a run around beater (civic) I didnt have time to do my normal check list.. fluids, brakes, belts,plugs, hoses, etc.. I knew it needed a headlight bulb so I ran into AZ or PB to grab 1... saw the Zmax so I grabbed it too... swapped the bulb an poured it in...an drove off... long story short. 2 months later I went to do my checks an realized the guy sold me the civic with almost NO OIL IN IT AT ALL!!! Less than a quart of oil an Zmax... (and no leaks were found).. and I drove the beater like I stole it.. so it wasn't babied.it never seized or gave me any issues. So ever since new or used my cars get Zmax....
Enjoy your Ls. Im at 120k miles an mine rides like a dream!!!!!
Enjoy your Ls. Im at 120k miles an mine rides like a dream!!!!!
Last edited by Shibumi1; Sep 1, 2014 at 05:33 AM.
Lead Lap
Joined: Aug 2012
Posts: 458
Likes: 7
From: KY
There is definitely a wealth of information on this forum and it most certainly has help me with my purchase decision, thanks to all! I recently bought a 2011 460 L, CPO with 28,350 miles. Cooperate Lease vehicle. I love the looks and how it drives, smooth! But I do have a concern. Before I go to the dealer I thought I would educate myself from the experienced LS owners. I am hearing a very brief (1-2 seconds) mild engine knock at a cold startup. This only occurs when the engine is cold and has sat overnight. It never happens after this first startup, even after turning the engine off and then on again. It kinda sounds like the oil isn't getting where it should be for a few seconds. Engine sounds great with normal and hard acceleration throughout the day. The dealership where I bought it is 300 miles away, so I would be taking it to a local dealership. Now I did hear this noise and mentioned it to the service manager when I first bought the car, and the service manager told me that this cold startup sound is normal. He also mentioned the direct injectors at idle. I guess sometimes it's hard to fully trust what dealerships say. Is he right? Any ideas?
CL Community Team
Joined: Apr 2008
Posts: 2,221
Likes: 310
From: TX
There is definitely a wealth of information on this forum and it most certainly has help me with my purchase decision, thanks to all! I recently bought a 2011 460 L, CPO with 28,350 miles. Cooperate Lease vehicle. I love the looks and how it drives, smooth! But I do have a concern. Before I go to the dealer I thought I would educate myself from the experienced LS owners. I am hearing a very brief (1-2 seconds) mild engine knock at a cold startup. This only occurs when the engine is cold and has sat overnight. It never happens after this first startup, even after turning the engine off and then on again. It kinda sounds like the oil isn't getting where it should be for a few seconds. Engine sounds great with normal and hard acceleration throughout the day. The dealership where I bought it is 300 miles away, so I would be taking it to a local dealership. Now I did hear this noise and mentioned it to the service manager when I first bought the car, and the service manager told me that this cold startup sound is normal. He also mentioned the direct injectors at idle. I guess sometimes it's hard to fully trust what dealerships say. Is he right? Any ideas?
Here are some links to threads that might provide some insight:
https://www.clublexus.com/forums/ls4...e-in-idle.html
https://www.clublexus.com/forums/ls4...t-low-rpm.html
https://www.clublexus.com/forums/ls4...-problems.html
https://www.clublexus.com/forums/ls4...wd-normal.html
If the service manager tells you this is "normal", ask him to show it to you on any other car at the dealership. You'll soon determine that it is only "normal" on your car! The injector clicking is constant on these cars, hot or cold, not just at startup.
Thread Starter
Rookie
Joined: Aug 2014
Posts: 63
Likes: 4
From: CA
Thanks for the info everyone! So after 1000 miles I changed changed the oil. OEM filter and 0-20 mobile one synthetic. I did this just to feel comfortable knowing the oil was fresh. Yes the dealer had it serviced preparing it for sale, but I did notice the oil was not new like a fresh oil change should look. At the very end of the draining of oil, it got really dark. The oil filter element was pretty dark too. I have a 2012 Toyota Camry with the same filter cartridge setup and change it every 5000 miles. This one looked a lot more soiled yet only had a 1000 miles or so on it. At least that's what the records show. Now I know this is crazy, but the engine now sounds a lot quieter. No knocking at startup. At idle (this is really strange, but the injector noise is quieter). The injectors have nothing to do with oil, do they? Hey, I'll take what I can get. I will drive it for a week or so and see if the sound returns. Always keep one foot on dry pavement 
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Lexus Fanatic
Joined: Jan 2014
Posts: 5,371
Likes: 526
From: BC Canada
Mobil 1 is known for cleaning dirty engines, so that's probably whats going on. Dirty oil may have an effect on the VVT system our cars have, which would explain the imoproved driveability. I know that's what has been happenning when I ran Rislone Engine Treatment in my car. Once I drain that out, I will use only Toyota 0W20 as it's my understanding that this oil has the neccessary aditives to work with the VVT. As otheres have experienced here, my car hesitated and lacked throttle response immediately after an oil change. I eliminated that with the engine cleaning.
As a precaution, every other oil change I may add a bottle of AutoRX Pro to keep it clean.
And props to member DevH for some of his research and suggestions here at CL regarding the above.
As a precaution, every other oil change I may add a bottle of AutoRX Pro to keep it clean.
And props to member DevH for some of his research and suggestions here at CL regarding the above.
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Thread Starter
Rookie
Joined: Aug 2014
Posts: 63
Likes: 4
From: CA
This sounds very close to what a Lexus tech said to me. He mentioned three components, one of which I think was the variable valve timing, and other related components. I wish I could remember. He said for a few seconds oil does not lubricate up there, but would not pose a problem since a film of oil exist. He said very important to use the 0-20. I'm definitely going to change the oil after 1000 miles to make sure everything is clean. Cheap insurance for around 50.00. Thanks.
Thread Starter
Rookie
Joined: Aug 2014
Posts: 63
Likes: 4
From: CA
Thanks ClassicSC3, I'm going to send an oil sample to Blackstone Labs upon my next oil change. Hopefully this will tell me how well this LS was maintained. It's a cooperate lease with service every 5000 miles, according to the paperwork.
Racer
Joined: Dec 2013
Posts: 1,657
Likes: 45
From: Maryland
The Direct Injection system has everything to do with oil. The Direct Injection pumps are run off the cams and that is how they achieve those high fuel pressures. DI noise is typical for most vehicles that use it and it's a common complaint. Some of the newer vehicles are employing sound reduction shielding around the head to lessen the noise.
When you start your car there is not enough oil viscosity between the cam and the pump and that is the source of the noise. As the oil heats up it builds up viscosity and thickens to add a cushion between those moving parts and it dampens the noise.
Even if you use Toyota Synthetic oil the noise will still be there however Toyota oil has very high Viscosity index and it will adjust quickly. I don't think the initial metal to metal contact with the pump and the cam will cause any issue with premature wear and it's just a quirk.
When you start your car there is not enough oil viscosity between the cam and the pump and that is the source of the noise. As the oil heats up it builds up viscosity and thickens to add a cushion between those moving parts and it dampens the noise.
Even if you use Toyota Synthetic oil the noise will still be there however Toyota oil has very high Viscosity index and it will adjust quickly. I don't think the initial metal to metal contact with the pump and the cam will cause any issue with premature wear and it's just a quirk.
Racer
Joined: Dec 2013
Posts: 1,657
Likes: 45
From: Maryland
Mobil 1 is known for cleaning dirty engines, so that's probably whats going on. Dirty oil may have an effect on the VVT system our cars have, which would explain the imoproved driveability. I know that's what has been happenning when I ran Rislone Engine Treatment in my car. Once I drain that out, I will use only Toyota 0W20 as it's my understanding that this oil has the neccessary aditives to work with the VVT. As otheres have experienced here, my car hesitated and lacked throttle response immediately after an oil change. I eliminated that with the engine cleaning.
As a precaution, every other oil change I may add a bottle of AutoRX Pro to keep it clean.
And props to member DevH for some of his research and suggestions here at CL regarding the above.
As a precaution, every other oil change I may add a bottle of AutoRX Pro to keep it clean.
And props to member DevH for some of his research and suggestions here at CL regarding the above.
I don't think you need to keep adding AutoRX. I would say one treatment with a flush cycle is more then enough. There is no risk to performing more treatments but I think it would be a waste of money if the engine is clean and is kept clean because you are now using Synthetic.
Last edited by Devh; Sep 1, 2014 at 08:22 PM.
Thread Starter
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Joined: Aug 2014
Posts: 63
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From: CA
Wow that's good to know about Toyota 0-20 synthetic. I was reading my 30,000 mile service performed by the Lexus dealership. It says they also performed a flush with a "carbon cleaner flush kit" number 01661, also a "premium kit 15" number 02411. Maybe this is why my oil was not fresh looking, and according to some readings on the net, carbon does build up on the back of our valves, due to direct injection. Does anyone know what the carbon flush entails, and what is "the premium 15"? By the way, it was to the tune of 1300.00. Glad I did not pay it!
Racer
Joined: Dec 2013
Posts: 1,657
Likes: 45
From: Maryland
Wow that's good to know about Toyota 0-20 synthetic. I was reading my 30,000 mile service performed by the Lexus dealership. It says they also performed a flush with a "carbon cleaner flush kit" number 01661, also a "premium kit 15" number 02411. Maybe this is why my oil was not fresh looking, and according to some readings on the net, carbon does build up on the back of our valves, due to direct injection. Does anyone know what the carbon flush entails, and what is "the premium 15"? By the way, it was to the tune of 1300.00. Glad I did not pay it!
Our DI systems are uniquely different in that they have both direct and port injection. The port injection has some advantages one of which can prevent the carbon build up on the back of the valves which seems to be the weak point with DI only systems.
Another concern is if the maintenance like oil changes were performed every 5k miles.
I would go to the Lexus drivers site and register. Enter in your Vin number and you will be able to see the cars service history. If the cars oil was not changed for an extended period of time because it was a corporate leases vehicle that the company decided not to change the oil because of laziness then I would raise some hell with the CPO management.
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