RX400H sudden knocking sound
04-15-24, 03:04 PM
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RX400H sudden knocking sound
I have 2007 RX400H. I have 187000 miles and I change my oil via Greese Monkey, atlanta, very 3000 miles. One morning I started my car and it sounded like someone was kicking a can down the street, when I pulled out of drive way. Anyways, the diagnostic codes were: P0300, P0303, P0306. The first mechanic said that I should change spark plugs, mantifold piece, and oil change/filter. ok I changed. The knocking sound increased. The second mechanic said that I actually needed a new engine, because I had a engine rod issue. After letting another mechanic hear my recording of my car sound, he too said I needed knew engine. Im not sure what to think. The sound just started one morning. My car has never overheated and does not have a oil leak so I don't know what to do? It doesn't make any since to me that I need a whole new engine. Can someone tell me if they have had this issue with their second gen Lexus RX400h
04-15-24, 04:51 PM
#2
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Timing belt flopping around? Doesn't have the characteristic sharp knock sound of bad rod bearings but need to hear the engine revving up and down I know not easy on a hybrid.
04-16-24, 08:02 AM
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OMG Thak you for your feed back. I really don't have the $2800 to spend for replacement engine....ok im gonna re-record the sound with the hood up. I'll up load this eve after work.
04-16-24, 09:14 AM
#7
Recording a sound does pretty much nothing to diagnose the problem
My opinion:
Your 1st mechanic is completely worthless. Spark plugs are not likely the issue they can be easily tested but they are quite laborous to change the rear ones so lots of money to be made, oil change/filter have zero to do with your initial problem unless he poped them off to check for metallic shavings but they are not the cause of the noise. The fact that you paid him yet left there with the same issues is crazy as he did not remedy your problems. There is a simple procedure to tell if the misfire is due to spark plugs, your coiil pack, or something else perhaps share with us the procedures that he did. Is this mechanic a Toyota/Lexus specialist or Cletus from Bubba's garage and feed store? How qualifed is this person?
2nd mechanic - what exactly did he do to diagose you're need for a new engine? What did he tell you he did to come to that conclusion and why are you not giving this forum that vital information if you're looking for qualified and knowledgable answers?
Bad coil packs and bad spark plugs do not make noises, they make your car run terribly rough
If your goal is to get to the solution quickly and in the least costly manner - Stop throwing money at mechanics lettng them run amuck on your car... you're not asking very direct questions therefore not getting very direct answers that are crutial here. They LOVE when customers don't do their homework, that is an open check for them to write as you're seeing now.You'll never get any good solutions until you ask the right questions AND give the right, accurate information.
What changed recently on your car just prior to your problems? Have any work done recently? Has it sat for awhile? When was your last full service (plugs, filters, etc)? Were the plugs changed at 100K miles or have they been replaced at all ever? Ever run it low on oil? Have you checked the oil level and was it ever low? Have the coil packs ever been replaced? If so were they OEM or aftermarket? What is code reading stating now (what codes?). Is it a Techstream or other reader? Do not drive the car at all in this condition as you will likely cause fatal damage if it is not already there... how far did you drive the car after first hearing this sound and seeing these codes?
You sound very scared, and you should be, that is not from what you know it is from what you do not know... take a breath, follow simple procedures, get answers, proceed from there making SMART decisions. Do not drive the car under any circumstance, if you need it worked on have it towed. This could be something very inepxensive and simple or maybe not but driving it will definitely cost you. Think like Elon Musk with the "first principle approach" - a brilliant way of looking at any problem or challenge. Tell what you KNOW NOT what you think, feel, or someone said... what tests did the mechanics do in order to come up with these supposed codes and solutions? Find the problem THEN impliment solutions, stop throwing money at possible solutions until yo know what the problem actually is and that can't come until certain test procedures are done OR you can keep throwing cash at unqualified people on "hopium" and eventually get a new-to-you engine that you know nothing about where the labor to install alone will liklely be >$2K.
My opinion:
Your 1st mechanic is completely worthless. Spark plugs are not likely the issue they can be easily tested but they are quite laborous to change the rear ones so lots of money to be made, oil change/filter have zero to do with your initial problem unless he poped them off to check for metallic shavings but they are not the cause of the noise. The fact that you paid him yet left there with the same issues is crazy as he did not remedy your problems. There is a simple procedure to tell if the misfire is due to spark plugs, your coiil pack, or something else perhaps share with us the procedures that he did. Is this mechanic a Toyota/Lexus specialist or Cletus from Bubba's garage and feed store? How qualifed is this person?
2nd mechanic - what exactly did he do to diagose you're need for a new engine? What did he tell you he did to come to that conclusion and why are you not giving this forum that vital information if you're looking for qualified and knowledgable answers?
Bad coil packs and bad spark plugs do not make noises, they make your car run terribly rough
If your goal is to get to the solution quickly and in the least costly manner - Stop throwing money at mechanics lettng them run amuck on your car... you're not asking very direct questions therefore not getting very direct answers that are crutial here. They LOVE when customers don't do their homework, that is an open check for them to write as you're seeing now.You'll never get any good solutions until you ask the right questions AND give the right, accurate information.
What changed recently on your car just prior to your problems? Have any work done recently? Has it sat for awhile? When was your last full service (plugs, filters, etc)? Were the plugs changed at 100K miles or have they been replaced at all ever? Ever run it low on oil? Have you checked the oil level and was it ever low? Have the coil packs ever been replaced? If so were they OEM or aftermarket? What is code reading stating now (what codes?). Is it a Techstream or other reader? Do not drive the car at all in this condition as you will likely cause fatal damage if it is not already there... how far did you drive the car after first hearing this sound and seeing these codes?
You sound very scared, and you should be, that is not from what you know it is from what you do not know... take a breath, follow simple procedures, get answers, proceed from there making SMART decisions. Do not drive the car under any circumstance, if you need it worked on have it towed. This could be something very inepxensive and simple or maybe not but driving it will definitely cost you. Think like Elon Musk with the "first principle approach" - a brilliant way of looking at any problem or challenge. Tell what you KNOW NOT what you think, feel, or someone said... what tests did the mechanics do in order to come up with these supposed codes and solutions? Find the problem THEN impliment solutions, stop throwing money at possible solutions until yo know what the problem actually is and that can't come until certain test procedures are done OR you can keep throwing cash at unqualified people on "hopium" and eventually get a new-to-you engine that you know nothing about where the labor to install alone will liklely be >$2K.
Last edited by Leeper; 04-16-24 at 09:35 AM.
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rlee777 (04-16-24)
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04-17-24, 02:51 PM
#8
FWIW, my RX350 sounded similar to a rod knock, but was actually a dropped valve due to a broken valve spring. Diagnosis was bad fuel trims on one bank, followed by a compression check, 0 on one cylinder. Fixed by doing a valve job on the heads. YMMV.
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MattRX (04-17-24)
04-17-24, 05:41 PM
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Recording a sound does pretty much nothing to diagnose the problem
My opinion:
Your 1st mechanic is completely worthless. Spark plugs are not likely the issue they can be easily tested but they are quite laborous to change the rear ones so lots of money to be made, oil change/filter have zero to do with your initial problem unless he poped them off to check for metallic shavings but they are not the cause of the noise. The fact that you paid him yet left there with the same issues is crazy as he did not remedy your problems. There is a simple procedure to tell if the misfire is due to spark plugs, your coiil pack, or something else perhaps share with us the procedures that he did. Is this mechanic a Toyota/Lexus specialist or Cletus from Bubba's garage and feed store? How qualifed is this person?
2nd mechanic - what exactly did he do to diagose you're need for a new engine? What did he tell you he did to come to that conclusion and why are you not giving this forum that vital information if you're looking for qualified and knowledgable answers?
Bad coil packs and bad spark plugs do not make noises, they make your car run terribly rough
If your goal is to get to the solution quickly and in the least costly manner - Stop throwing money at mechanics lettng them run amuck on your car... you're not asking very direct questions therefore not getting very direct answers that are crutial here. They LOVE when customers don't do their homework, that is an open check for them to write as you're seeing now.You'll never get any good solutions until you ask the right questions AND give the right, accurate information.
What changed recently on your car just prior to your problems? Have any work done recently? Has it sat for awhile? When was your last full service (plugs, filters, etc)? Were the plugs changed at 100K miles or have they been replaced at all ever? Ever run it low on oil? Have you checked the oil level and was it ever low? Have the coil packs ever been replaced? If so were they OEM or aftermarket? What is code reading stating now (what codes?). Is it a Techstream or other reader? Do not drive the car at all in this condition as you will likely cause fatal damage if it is not already there... how far did you drive the car after first hearing this sound and seeing these codes?
You sound very scared, and you should be, that is not from what you know it is from what you do not know... take a breath, follow simple procedures, get answers, proceed from there making SMART decisions. Do not drive the car under any circumstance, if you need it worked on have it towed. This could be something very inepxensive and simple or maybe not but driving it will definitely cost you. Think like Elon Musk with the "first principle approach" - a brilliant way of looking at any problem or challenge. Tell what you KNOW NOT what you think, feel, or someone said... what tests did the mechanics do in order to come up with these supposed codes and solutions? Find the problem THEN impliment solutions, stop throwing money at possible solutions until yo know what the problem actually is and that can't come until certain test procedures are done OR you can keep throwing cash at unqualified people on "hopium" and eventually get a new-to-you engine that you know nothing about where the labor to install alone will liklely be >$2K.
My opinion:
Your 1st mechanic is completely worthless. Spark plugs are not likely the issue they can be easily tested but they are quite laborous to change the rear ones so lots of money to be made, oil change/filter have zero to do with your initial problem unless he poped them off to check for metallic shavings but they are not the cause of the noise. The fact that you paid him yet left there with the same issues is crazy as he did not remedy your problems. There is a simple procedure to tell if the misfire is due to spark plugs, your coiil pack, or something else perhaps share with us the procedures that he did. Is this mechanic a Toyota/Lexus specialist or Cletus from Bubba's garage and feed store? How qualifed is this person?
2nd mechanic - what exactly did he do to diagose you're need for a new engine? What did he tell you he did to come to that conclusion and why are you not giving this forum that vital information if you're looking for qualified and knowledgable answers?
Bad coil packs and bad spark plugs do not make noises, they make your car run terribly rough
If your goal is to get to the solution quickly and in the least costly manner - Stop throwing money at mechanics lettng them run amuck on your car... you're not asking very direct questions therefore not getting very direct answers that are crutial here. They LOVE when customers don't do their homework, that is an open check for them to write as you're seeing now.You'll never get any good solutions until you ask the right questions AND give the right, accurate information.
What changed recently on your car just prior to your problems? Have any work done recently? Has it sat for awhile? When was your last full service (plugs, filters, etc)? Were the plugs changed at 100K miles or have they been replaced at all ever? Ever run it low on oil? Have you checked the oil level and was it ever low? Have the coil packs ever been replaced? If so were they OEM or aftermarket? What is code reading stating now (what codes?). Is it a Techstream or other reader? Do not drive the car at all in this condition as you will likely cause fatal damage if it is not already there... how far did you drive the car after first hearing this sound and seeing these codes?
You sound very scared, and you should be, that is not from what you know it is from what you do not know... take a breath, follow simple procedures, get answers, proceed from there making SMART decisions. Do not drive the car under any circumstance, if you need it worked on have it towed. This could be something very inepxensive and simple or maybe not but driving it will definitely cost you. Think like Elon Musk with the "first principle approach" - a brilliant way of looking at any problem or challenge. Tell what you KNOW NOT what you think, feel, or someone said... what tests did the mechanics do in order to come up with these supposed codes and solutions? Find the problem THEN impliment solutions, stop throwing money at possible solutions until yo know what the problem actually is and that can't come until certain test procedures are done OR you can keep throwing cash at unqualified people on "hopium" and eventually get a new-to-you engine that you know nothing about where the labor to install alone will liklely be >$2K.
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