When I do a cold start, there is a 1 sec rattle. When I drive off, whenever the rpm crosses the ~1500rpm mark, there is a rattle sound. Only at that particular rpm. After 15mins of warm up, the rattle disappears completely! Is that piston slap? Im using SPC 0w30 oil. What should I do? Use a heavier viscosity oil? Get it scanned for any trouble codes? The CEL didnt light up though. It only has 20,000km on it.
Help! I think my 2002 Toyota 2.4L 2AZ-FE has developed piston slap!
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Piston slap does not sound like a rattle. Piston slap makes an engine sound almost like a diesel. If you have a ratteling noise it is probably in the valvetrain not in the pistons,rods or crank. It is more of a fast paced "clak,Clak,Clak".
I would start the engine up and listen carefuly!!! I might also use a stethascope to try to find the source of the sound. It is probably something really simple like loose exhast fastner or one of the acc. bolted to the engine!
I sure wish I could hear it.
You do have forged pistons and they do expand wich would take care of the slap but it would not take 15 minutes for them to expand! Temps on the piston range from 400-3000 degree's F dependine on the location on the piston. At those temps expansion happens quickly!
How many miles do you have on this engine?
P.S. Pay careful attention to the cat. converters these freg. develop a rattle now days since they switched to ceramic interiors!!!
I would start the engine up and listen carefuly!!! I might also use a stethascope to try to find the source of the sound. It is probably something really simple like loose exhast fastner or one of the acc. bolted to the engine!
I sure wish I could hear it.
You do have forged pistons and they do expand wich would take care of the slap but it would not take 15 minutes for them to expand! Temps on the piston range from 400-3000 degree's F dependine on the location on the piston. At those temps expansion happens quickly!
How many miles do you have on this engine?
P.S. Pay careful attention to the cat. converters these freg. develop a rattle now days since they switched to ceramic interiors!!!
Also think oil flow. If you are using a restrictive oil filter, you could be not getting enough cold oil where it needs to be. The only reason the noise stops is the oil thins as it gets warmer, negating the restriction.
Somebody posted this before... I doubt it but does your Toyota sounds like this?
http://www.pistonslap.com/photos.htm
Could it be carbon deposits on the valves? Such low milage though...
http://www.pistonslap.com/photos.htm
Could it be carbon deposits on the valves? Such low milage though...
I am just curious. What is piston slap, and what cause it?
Well, I have ruled out any CAT problem or driveshaft problem. When stationary in 'P', I cannot simulate the rattle. But when stationary in 'D', with left foot on the brake, I can simulate the rattle when I rev to ~1300rpm. The rattle is only at this rpm, anything higher or lower there is no rattle. It seems to be coming from the left side of the engine, near the serpentine belt area. But it is not belt slip, it is a loud rattle sound. It is unlikely to be bearing related either, bearings dont make this sort of rattle. It is not AC problem either, rattle also occurs with or without AC switched on. I suspect now it is a more serious internal engine problem. Maybe a Timing Chain rattle or a hydraulic VVTi problem.
Ken4 have you had your dealer listen to it yet? Your van is still under powertrain waranty correct? Usualy timing chain tensioners make the most noise at start up. Most engines sounds are not dependent on tramission being enguaged. It sounds like it could also be a trany issue.
In amodern engine you can not tell what is makeing the noise based on location of radiated sound. Modern engine made out of aluminum can transmit the noise from were the problem is to an entirely un related point. Usualy it is not mechanical if the problem only happens at one rpm. Mechanical problems will always be their. It trully sounds like a resonce problem. In [D] at 1300 RPM's you are probably hitting the resonate freq. for what ever part you are hearing.
A good well seasoned mechanic should be able to tell you what the sound is in about 3 seconds. It would be about like asking a composer to identify the instrement he hears. It really is a no brainer. The better the mechnic knows the powertrain the more reliable the diagnosis.
In amodern engine you can not tell what is makeing the noise based on location of radiated sound. Modern engine made out of aluminum can transmit the noise from were the problem is to an entirely un related point. Usualy it is not mechanical if the problem only happens at one rpm. Mechanical problems will always be their. It trully sounds like a resonce problem. In [D] at 1300 RPM's you are probably hitting the resonate freq. for what ever part you are hearing.
A good well seasoned mechanic should be able to tell you what the sound is in about 3 seconds. It would be about like asking a composer to identify the instrement he hears. It really is a no brainer. The better the mechnic knows the powertrain the more reliable the diagnosis.
Mine only has a 1yr warranty. In fact mine is not an isolated case, there seems to be many Toyota van owners in Singapore with exactly the same problem. From what I hear from others, the dealer has not been able find a permanent fix for this problem. One owner reported that the tensioner was replaced twice, but each time the fix only lasted about 2,000km before the rattle came back. Im also not sure whether he was talking about the serpentine belt tensioner or the timing chain tensioner. How is the timing chain tensioner replaced anyway? Isnt it an internal thing? It appears like Toyota has a poorly designed timing chain system.
I am scepticle that it is related to the tranny, bcos there seems to be no noise coming from the right side (tranny side) of the engine. Noise is coming from the left side (serpentine belt side) of the engine.
I am scepticle that it is related to the tranny, bcos there seems to be no noise coming from the right side (tranny side) of the engine. Noise is coming from the left side (serpentine belt side) of the engine.
Hen4 I checked my car out last night. I belive what you are hearing is typical timeing chain and ballance shaft noise. When you have a dual overhead cam engine with ballance shafts and a chain you get a harmonic clanking sound at a given rpm. Most cars with DOHC and Ballance shafts make this noise at idle. It would appear that ours does it 1300 RPMS. I managed to get my car to make the noise at that rpm standing still. I listened with the window down and up.
It would apear that they shifted the rpm were the harmonics occur to an RPM setting that would not typicaly happen sitting still. I have to assume that the NVH guys figured that road noise would drown it out.
At the moment I can not remember what the noise is called but it is common on all DOHC engines with ballance shafts. If the tensior was bad for the timeing chain it would make a load claking noise on start up and would either go away once oil was flowing or it would continue non-stop.
It would apear that they shifted the rpm were the harmonics occur to an RPM setting that would not typicaly happen sitting still. I have to assume that the NVH guys figured that road noise would drown it out.
At the moment I can not remember what the noise is called but it is common on all DOHC engines with ballance shafts. If the tensior was bad for the timeing chain it would make a load claking noise on start up and would either go away once oil was flowing or it would continue non-stop.
You may be thinking of resonance.
The automobile can be thought of as a complex vibrating system - powered by the engine with its reciprocating components and intermittent combustion.
When these modern designs are computer modeled, various structures are treated as a series of mass-spring-damper systems. There are hundreds of mass-spring-dampers for modelling purposes. Each may vibrate in multiple modes at different frequencies, so you can multiply those modes times the various structures. The masses and springs are reasonably straightforward to quantify, and so the frequency of the modes can be predicted with acceptable accuracy.
Without damping a system will vibrate, when excited, at any of the modes' natural frequencies with a high amplitude. Damping spreads out the modes' frequencies and reduces amplitude.
Thanks John! This article is the only thing I have that shows some internals of the 2AZ-FE. I dont believe the balance shafts are related bcos as you can see, it is driven by a crankshaft gear and not the timing chain. And this problem also plagues the smaller 2.0L variant 1AZ-FE which doesnt have any balance shafts. I am now more inclined to believe it is primarily a Timing Chain problem. Maybe after 20,000km, the Timing Chain begins to stretch and rattling starts? I wish I had a Haynes Manual to see how I could tighten or replace the timing chain tensioner. But Haynes seems to be rather slow in producing one for the 2AZ-FE.
In the meantime, I am going to try an Auto-RX treatment (amazing, I can find it in Singapore now!) first to see if cleaning up the internals helps. Followed by maybe a thicker viscosity 50wt oil. I am also going to try and record this sound for all you guys to hear.
In the meantime, I am going to try an Auto-RX treatment (amazing, I can find it in Singapore now!) first to see if cleaning up the internals helps. Followed by maybe a thicker viscosity 50wt oil. I am also going to try and record this sound for all you guys to hear.
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Check if any of your spark plugs are loose.
Ken4, I will have to get some speaker down to the basment and hook them up but I will do it and take a listen.
Toyota developed a special polymere to Dapen the harmonics of the ballance shafts. They also made the gears out of a resin.
I wish I still had access to SAE dockuments. I lost my job so I no longer have access. Their is an SAE paper on the 2AZ-FE engine.
The gear on the crank is stell but the drive gears on the ballance shafts are resin. The resin gears are joined to the ballance shafts with a dapening polymer that is far better then anything that has been used before. The engine uses one large timeing chain and a large pulley/drum like wheel to reduce strain on the chain. I am typeing this from memory so I might have missed something.
Take a listen to any other DOHC engine with Dual ballance shafts (preferably from 1980's to early 1990's) at idle and you will hear the noise I am reffering too. If you listen carefuly you can hear the two primary freq.'s and then the intermod harmonics. The primary freq.'s sound mechanical and the harmonics will sound like a mutted slapping noise over lapping the mechanical sounds.
Toyota developed a special polymere to Dapen the harmonics of the ballance shafts. They also made the gears out of a resin.
I wish I still had access to SAE dockuments. I lost my job so I no longer have access. Their is an SAE paper on the 2AZ-FE engine.
The gear on the crank is stell but the drive gears on the ballance shafts are resin. The resin gears are joined to the ballance shafts with a dapening polymer that is far better then anything that has been used before. The engine uses one large timeing chain and a large pulley/drum like wheel to reduce strain on the chain. I am typeing this from memory so I might have missed something.
Take a listen to any other DOHC engine with Dual ballance shafts (preferably from 1980's to early 1990's) at idle and you will hear the noise I am reffering too. If you listen carefuly you can hear the two primary freq.'s and then the intermod harmonics. The primary freq.'s sound mechanical and the harmonics will sound like a mutted slapping noise over lapping the mechanical sounds.
Ken4, I just checked TSB's for 2003 Camry with 2AZ-FE engine. THeir are no powertrain mechanical "TSB's" or "Recall's"! Their are some gimpy things like reselling windshield, replaceing weather seals, how to reprogram the ECU etc..... Their is nothing to show or denote any type of mechanical problem with the engine or transmission. No slap, no valvetrain issues etc....
If your Van has a genuine issue it is not a pandemic design fualt but a mere parts failure! One way customers used to get around paying me for my time was to bring it in for an oil change. They would then mention to the service writer that it was makeing a strange noise. They then got my professional opion for free or next to free. If it sounded serious I would tell the service writer that it needed a thourogh work up! So for the price of an oil change they were able to buy piece of mind! Some places will listen to it for free and tell you if they think you need to have it looked at more closely.
If your Van has a genuine issue it is not a pandemic design fualt but a mere parts failure! One way customers used to get around paying me for my time was to bring it in for an oil change. They would then mention to the service writer that it was makeing a strange noise. They then got my professional opion for free or next to free. If it sounded serious I would tell the service writer that it needed a thourogh work up! So for the price of an oil change they were able to buy piece of mind! Some places will listen to it for free and tell you if they think you need to have it looked at more closely.
#1. Don't hit the gas when you first start the engine. It's very bad for it.
#2. It was very hard to listen to the motor with that recording. Something like this needs to be done in real life. Nevertheless if I had to take a wild guess, I'd wild guess it is something being driven on the outside of the motor, like an air pump or something. I'm not familliar with what is hanging off of your motor, so I really don't know.
Have you tried taking a length of hose and putting one end close to (not into!) your ear and using the other end like a stethescope? But really, just take it to a good mechanic who will tell you what it is in 20 seconds.
#2. It was very hard to listen to the motor with that recording. Something like this needs to be done in real life. Nevertheless if I had to take a wild guess, I'd wild guess it is something being driven on the outside of the motor, like an air pump or something. I'm not familliar with what is hanging off of your motor, so I really don't know.
Have you tried taking a length of hose and putting one end close to (not into!) your ear and using the other end like a stethescope? But really, just take it to a good mechanic who will tell you what it is in 20 seconds.
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