oil change+new tank of gas= ROD KNOCK?
08-16-10, 08:16 AM
#16
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Thanks guys. I will change the oil. The car runs perfectly other than this weird knock sound at idle (you cant even hear it in traffic) like someome is taking a rubber strip similar to a belt, spinning it around in circles and having the tail end of it repeatedly hit a wooden table.
08-16-10, 08:54 AM
#17
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We are going to find out very soon. As soon as I can get all my parts in this week (ignition stuff) I will crack open the front and have a look while replacing stuff. If it breaks in the meantime, it will leave me stranded but it won't tear anything up.
08-16-10, 06:02 PM
#18
How hard is it to pull the serpentine on these cars? The first thing I like to do in these situations is run it for a bit with no belt to rule out all driven accessories. If the noise goes away with no acc belt, start looking at accessories, obviously... Its a fast and easy way to rule out alot of spinning potential noise-makers.
08-20-10, 03:52 PM
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My 1995 sc400 does the EXACT same thing. I have been to 9 different mechanics...one said it was rod knock and the others had no idea what it was and that it was NOT rod knock. The one mechanic, I believe, was frivolous.
PM me when you can, I have done a lot of research on this...maybe we can figure it out.
PM me when you can, I have done a lot of research on this...maybe we can figure it out.
08-20-10, 06:43 PM
#21
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I decided to go ahead and change out the valve cover gaskets when I do the plugs and wires. This will put me back a week so the gaskets and such can come in. At that time, I will change the oil to a 10W 30. What I can say is there is no way (I think) that it is rod knock. I did a 40-90 pull and it was smooth all the way up.
08-20-10, 06:47 PM
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My 1995 sc400 does the EXACT same thing. I have been to 9 different mechanics...one said it was rod knock and the others had no idea what it was and that it was NOT rod knock. The one mechanic, I believe, was frivolous.
PM me when you can, I have done a lot of research on this...maybe we can figure it out.
PM me when you can, I have done a lot of research on this...maybe we can figure it out.
08-20-10, 09:46 PM
#23
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"Oil on the dipstick shows right in the middle of low and full"
the oil level should be right on the full mark.
10w-30 is the correct weighted oil to use.
sounds like you need to reshim. $12aud each x 32.
have you thought about some aftermarket cams?
the oil level should be right on the full mark.
10w-30 is the correct weighted oil to use.
sounds like you need to reshim. $12aud each x 32.
have you thought about some aftermarket cams?
08-20-10, 10:11 PM
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beat me to it, If your oil level is sitting at half , you need to top it up !!!
all the way to full.
At low revs the oil is probably not circulating properly if its low, and 5 litres of oil should be on full , a filter will also take about 300-400mls , so maybe just needs a bit more.
Not sure about American fuel and spec car, but japanese spec car has knock sensors and prefers high octane fuel to run properly.
Did you put low octane in , and the knock sensors are pulling some timing out , that is only evident , at idle ???
Also ICV, could be sticking alittle , affecting idle quality.
just some thoughts.
all the way to full.
At low revs the oil is probably not circulating properly if its low, and 5 litres of oil should be on full , a filter will also take about 300-400mls , so maybe just needs a bit more.
Not sure about American fuel and spec car, but japanese spec car has knock sensors and prefers high octane fuel to run properly.
Did you put low octane in , and the knock sensors are pulling some timing out , that is only evident , at idle ???
Also ICV, could be sticking alittle , affecting idle quality.
just some thoughts.
08-21-10, 06:02 AM
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One thing may be the valves need to be readjusted with new shims. That is over my head on how to measure that. Some say piston slap? Exhaust leak? Who knows lol. What has your research shown? I will be replacing the valve cover gaskets when I do the plugs so I'll get a good look at the cams. I am just wainting on the parts to come it.
My only research has been to take the car to many mechanics. I went to one place where they lifted the car up and allowed me to stay in so that I could apply the brake and keep the car in drive. The mechanic had a listening device similar to a device that doctors use to listen to your heart. Anyway, he couldn't hear anything. I think he thought I was crazy haha!
The latest mechanic I went to is a buddy of mine who is a Lexus mechanic who works at Lexus. He did find the knocking noise where you found yours...on the left side of the engine bay (he used a stick like piece of wood to find the location). He has no idea what it is, but, like the other mechanics who heard it, except for the one who thought it was rod knock, he told me I shouldn't worry about it unless it gets worse.
The only mechanic who thought it was rod knock told me it could throw a rod at any time and then quoted me a charge of 3k to rebuild my engine. Seeing as how every other mechanic disagreed, and in realizing that these v8s are nearly bulletproof, I am convinced it is not rod knock. I just bought my car about 3 months ago from a doctor who was the original owner. The carfax shows him taking to Lexus for every service recommended in the manual. My car has 120k miles on it, and, even after 3k miles, the oil is still super clean as if it was just put in there.
One thing though, I never heard the sound until I put magnaflows on my car. When I did this, I had one of the cats taken off, and, I removed the resonator(s). So now all that I have are 2 cats and magnaflows.
I am now to the point where the sound does not bother me. I have been using 10w-30 and the sound is still there. HOWEVER, I will never notice unless I am pulling into my quiet garage with the car warmed up, windows down, ac off, car stopped, in drive etc. And there are some days where I can't hear it all in such conditions, and others where I notice it right off. I honestly believe that there are many other sc400s out there making the same noise, but it is such a quiet noise, maybe most people never notice.
At any rate, I would really love to know what the noise is. Please let me know if you find out what it is. I will, in the meantime, be ignoring mine unless I break down somewhere lol
08-21-10, 10:09 AM
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My only research has been to take the car to many mechanics. I went to one place where they lifted the car up and allowed me to stay in so that I could apply the brake and keep the car in drive. The mechanic had a listening device similar to a device that doctors use to listen to your heart. Anyway, he couldn't hear anything. I think he thought I was crazy haha!
The latest mechanic I went to is a buddy of mine who is a Lexus mechanic who works at Lexus. He did find the knocking noise where you found yours...on the left side of the engine bay (he used a stick like piece of wood to find the location). He has no idea what it is, but, like the other mechanics who heard it, except for the one who thought it was rod knock, he told me I shouldn't worry about it unless it gets worse.
The only mechanic who thought it was rod knock told me it could throw a rod at any time and then quoted me a charge of 3k to rebuild my engine. Seeing as how every other mechanic disagreed, and in realizing that these v8s are nearly bulletproof, I am convinced it is not rod knock. I just bought my car about 3 months ago from a doctor who was the original owner. The carfax shows him taking to Lexus for every service recommended in the manual. My car has 120k miles on it, and, even after 3k miles, the oil is still super clean as if it was just put in there.
One thing though, I never heard the sound until I put magnaflows on my car. When I did this, I had one of the cats taken off, and, I removed the resonator(s). So now all that I have are 2 cats and magnaflows.
I am now to the point where the sound does not bother me. I have been using 10w-30 and the sound is still there. HOWEVER, I will never notice unless I am pulling into my quiet garage with the car warmed up, windows down, ac off, car stopped, in drive etc. And there are some days where I can't hear it all in such conditions, and others where I notice it right off. I honestly believe that there are many other sc400s out there making the same noise, but it is such a quiet noise, maybe most people never notice.
At any rate, I would really love to know what the noise is. Please let me know if you find out what it is. I will, in the meantime, be ignoring mine unless I break down somewhere lol
The latest mechanic I went to is a buddy of mine who is a Lexus mechanic who works at Lexus. He did find the knocking noise where you found yours...on the left side of the engine bay (he used a stick like piece of wood to find the location). He has no idea what it is, but, like the other mechanics who heard it, except for the one who thought it was rod knock, he told me I shouldn't worry about it unless it gets worse.
The only mechanic who thought it was rod knock told me it could throw a rod at any time and then quoted me a charge of 3k to rebuild my engine. Seeing as how every other mechanic disagreed, and in realizing that these v8s are nearly bulletproof, I am convinced it is not rod knock. I just bought my car about 3 months ago from a doctor who was the original owner. The carfax shows him taking to Lexus for every service recommended in the manual. My car has 120k miles on it, and, even after 3k miles, the oil is still super clean as if it was just put in there.
One thing though, I never heard the sound until I put magnaflows on my car. When I did this, I had one of the cats taken off, and, I removed the resonator(s). So now all that I have are 2 cats and magnaflows.
I am now to the point where the sound does not bother me. I have been using 10w-30 and the sound is still there. HOWEVER, I will never notice unless I am pulling into my quiet garage with the car warmed up, windows down, ac off, car stopped, in drive etc. And there are some days where I can't hear it all in such conditions, and others where I notice it right off. I honestly believe that there are many other sc400s out there making the same noise, but it is such a quiet noise, maybe most people never notice.
At any rate, I would really love to know what the noise is. Please let me know if you find out what it is. I will, in the meantime, be ignoring mine unless I break down somewhere lol
or sound, I don't know if you could call it a problem. I have it narrowed down in my brain to 3 things. 1. loose spark plug knocking around in the tube. (2) exhaust leak that only presents itself at such low rpms because at higher rpms, the pressure and flow is high enough to not leak. (3) Need new shims for the camshafts. The only reason I put 5w30 oil in is because that's what it calls for in the manual and on the oil cap. I'll be doing the tune up as soon as my parts come in. At that time, I'll atleast be able to check the plugs to rule that one out. I'll be looking at the camshafts too but I won't know what I'm looking for
08-21-10, 10:15 AM
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beat me to it, If your oil level is sitting at half , you need to top it up !!!
all the way to full.
At low revs the oil is probably not circulating properly if its low, and 5 litres of oil should be on full , a filter will also take about 300-400mls , so maybe just needs a bit more.
Not sure about American fuel and spec car, but japanese spec car has knock sensors and prefers high octane fuel to run properly.
Did you put low octane in , and the knock sensors are pulling some timing out , that is only evident , at idle ???
Also ICV, could be sticking alittle , affecting idle quality.
just some thoughts.
all the way to full.
At low revs the oil is probably not circulating properly if its low, and 5 litres of oil should be on full , a filter will also take about 300-400mls , so maybe just needs a bit more.
Not sure about American fuel and spec car, but japanese spec car has knock sensors and prefers high octane fuel to run properly.
Did you put low octane in , and the knock sensors are pulling some timing out , that is only evident , at idle ???
Also ICV, could be sticking alittle , affecting idle quality.
just some thoughts.
08-21-10, 05:15 PM
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I'm not sure wether thats the right fuel to be honest.
In Australia we have 91 ron ,95ron ,an 98 RON.
The 98 is the only suitable fuel for our cars , as they are japanese spec , and Jap fuel is over 100 ron.
I'm sure it been discussed plenty on here , maybe someone can confirm that 92 is ok for US spec sc400's but if I was you , I would be using higher Octane fuel, if it's available.
cheers,
In Australia we have 91 ron ,95ron ,an 98 RON.
The 98 is the only suitable fuel for our cars , as they are japanese spec , and Jap fuel is over 100 ron.
I'm sure it been discussed plenty on here , maybe someone can confirm that 92 is ok for US spec sc400's but if I was you , I would be using higher Octane fuel, if it's available.
cheers,
08-21-10, 09:35 PM
#29
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I'm not sure wether thats the right fuel to be honest.
In Australia we have 91 ron ,95ron ,an 98 RON.
The 98 is the only suitable fuel for our cars , as they are japanese spec , and Jap fuel is over 100 ron.
I'm sure it been discussed plenty on here , maybe someone can confirm that 92 is ok for US spec sc400's but if I was you , I would be using higher Octane fuel, if it's available.
cheers,
In Australia we have 91 ron ,95ron ,an 98 RON.
The 98 is the only suitable fuel for our cars , as they are japanese spec , and Jap fuel is over 100 ron.
I'm sure it been discussed plenty on here , maybe someone can confirm that 92 is ok for US spec sc400's but if I was you , I would be using higher Octane fuel, if it's available.
cheers,
