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2005 Lexus LS430, 1993 Deville
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181 Posts
Discussion Starter #1
Hi,


I noticed a funny sound today when I got out of the car (car still running). I heard a ticking/knocking sound coming from the engine bay; it almost sounds like it is in sequence; it sounds like tick tick.................tick tick tick..........tick tick.........tick tick tick, sound is not that loud, you can't hear it in the cabin; it reapeats about every 4 sec. My guess would be something with one of the belts. It was very cold today, maybe that has something to do with it. I am kind of wondering what it could be. Thanks
 

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2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
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26,323 Posts
Most likely either the main accessory belt tensioner pulley, idler pulley, or water pump belt tensioner pulley. Did you open the hood? Which side is it louder on?
 

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2005 Lexus LS430, 1993 Deville
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Discussion Starter #4
Yes, I opened the hood. The funny thing is, it seems to be alittle bit more pronounced when the car warms up; nothing when it was cold, then alittle sound when the car is near operating temp. It sounds like it is strongest near the right rear of engine (looking at it from front). I checked the belts and pullys and they don't seem to be emitting the sound. Maybe it's nothing but maybe something is wrong. I would rather address now if something is wrong. Hopefully someone else out there has had the same issue and has explination. Thanks Guy's

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It kind of sounds like the noise in this video.......http://www.youtube.com/watch?v=XNambaeLp5o&lr=1&uid=70I13UKYI17g5ut2obl50Q


The main difference is; if I rev the engine, the noise does not rattle like this and it is not nearly as loud at idle.
 

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2005 Lexus LS430, 1993 Deville
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181 Posts
Discussion Starter #5
I just had the oil changed a few days ago. Maybe could be related?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,404 Posts
Who did the oil/filter change ?? Exactly what oil was used ? Have you personally verified proper oil level ?

Again - warm up the engine by driving at least 10 miles - open the hood and listen - accurately locate the tick. The list of possibilities is long, from valvetrain to water pump drive assembly.

You better pray that your noise is not like the one in the video - that's a rod knock or severe piston slap. Very expensive noise. Know that your valvetrain uses roller cam followers - very quiet when properly operating.
 

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2005 Lexus LS430, 1993 Deville
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181 Posts
Discussion Starter #7
I had it done at a local shop. I assume they used the correct oil, I have had it changed before with no problems. I will check it out today. Let me ask you this; if it was a rod knock or piston slap and I reved the engine, would the sound get worse like in the video? Because mine doesnt, engine sounds normal when reved. Thanks
 

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White Diamond '03 DHS (with DTS floor shift)
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If it was a rod knock or piston slap the sound would increase in repetition along with the RPM. Judging from your description of the location I'd guess at maybe the EGR valve or the AIR pump check valve.
 

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2005 Lexus LS430, 1993 Deville
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181 Posts
Discussion Starter #9
Ok, I just took it out for a drive; checked the oil (ok). When I started it up this morning I could not hear it, then when I got back I could hear it. I had someone rev the engine a few times to about 1700RPM while I stood in front; nothing; not only did it not get worse when we reved, but the engine seemed to drown it out, so my guess is it is not the engine. Hopefully just something small. I did notice that the water pump pully was kind of moving horizontaly on the bolt, very slightly; maybe thats it. If it is the water pump;EGR valve; air pump check valve could it exhibit the symtoms of wating until the engine is at full temp before manifesting?
 

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White Diamond '03 DHS (with DTS floor shift)
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If it is the water pump;EGR valve; air pump check valve could it exhibit the symtoms of wating until the engine is at full temp before manifesting?
:noidea: It shouldn't, but hard to say for sure.

Which W/P pulley was moving?

 

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2005 Lexus LS430, 1993 Deville
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Discussion Starter #11
Everything I see about rod knocking/Piston Slap indicates that the sound is worse when the engine is cold, then sound diminishes as engine warms. Is this true?

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The pully on the very top. Its the only one thats visible. Looks like the drive pully.
 

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2002 Deville
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If anything, a rod knock will get louder as it gets warmer. Piston slap usually only occurs when the engine is first started. As the piston warms up it expands and takes up the slop that causes the noise.
 

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White Diamond '03 DHS (with DTS floor shift)
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That pulley (W/P Drive Pulley) should have absolutely no movement other than rotation.

Piston slap aka "cold carbon rap" (on the Northstar) was more prevalent on the pre-2000 engines. It sounded just like a collapsed lifter. It was caused by carbon build up on the cylinder head in the low clearance area between the piston and the head aka "squish area", due to sedate driving (hence the WOT procedure). The piston would make contact at TDC and rotate on the wrist pin, causing the skirt to "slap" the cylinder wall. It would only last about 30-45 seconds and a good dose of WOT would cure it for quite some time.

Like Prostock said, a rod knock ain't going away.

I doubt either of these two are what you are hearing.
 

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2005 Lexus LS430, 1993 Deville
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Discussion Starter #14
Yes, it's strange. The sound is not very prevalent; I have looked at videos on YouTube of rod knock and when the people rev their engines it sounds like a machine gun. I would say the water pump pulley is moving laterally about maybe 1/16 on an inch on the shaft; hopefully that's the issue. So you would say that the pulley should not be moving laterally at all and if it is could that be a bad bearing or loose shaft? Thanks for the help guy's. I really appreciate it.

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Is it possible that it could be bad gas? I was thinking of putting some high test in it to see if that helps.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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If that water pump drive pulley is moving side to side then you have problems: That "shaft" is an extension of the left bank intake cam and the metal hub of the drive pulley is pressed on there with a force you would not believe. If the pulley is moving in and out, so is the camshaft. (and you would most likely have an oil leak at the intake cam/valve cover oil seal)

We're talking about the drive pulley - ~5" diameter, as opposed to the tensioner pulley, ~2" in diameter ???

Practically no such thing as "bad gas", at least in any station in any town on a traveled road in the U.S. Too much volume turnover - "high test" will do exactly nothing. If you want to play the fuel additive/cleanup game, dump in a 20 oz. jug of Chevron TECHRON and go for a 100 mile drive. Google "chevron techron" and "top tier gasoline" to find out why.
 

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2005 Lexus LS430, 1993 Deville
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181 Posts
Discussion Starter #16
Yes, 5" pulley; the one right on top. No oil leaks tho. The funny thing is this car has never lost any oil; I will go 4000-5000 miles between changes and it will still have the same amount. I am going to take it in to be checked tomorrow. Hopefully it will be something small like a stuck EGR valve. I will kepp you posted. I will try that chevron techron tho. Do you know of any places that do Northstar engine work in the Boston area? I don't know how far my garage goes with engine work; hopefully all the way beacuse they are resonable and good. Thanks
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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We're in the same oil consumption level - > 5,000 miles/quart - and if it ain't broke, don't fix it - in that department: Many CF members would kill to get half that oil mileage.

EGR would cause driveability and idle problems, no noise; probably set emissions codes, too.

We would really like to hear a YouTube of this noise....................YOUR noise
 

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2005 Lexus LS430, 1993 Deville
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181 Posts
Discussion Starter #20
I will see if I can get a video up tonight or tomorrow. What would you say is the most common culprit of ticking noises under the hood? My guess is that rod knock would be one of the less common, also seeing that this engine has only 70k on it. Submariner; this engine does not use 1 quart every 5k. I check oil levels regularly and I have never noticed it down even when it has been 4-5k miles and I am getting ready for oil change; but that could change as the engine gets more miles. Thanks
 
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