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Discussion Starter · #1 ·


The engine has been this way since new, and the salesman told me that this is normal, but now I am having some doubts. The noise frequency is approximately 1/4 or 1/6 (one-quarter or one sixs) of the engine RPM. It either means that one single cylinder valves are not adjusted properly, or this is the noise of the direct injection pump (that pumps the fuel once per engine cycle, as far as I understand, and this also would be 1/4 of RPM). The noise is coming from the rear passenger cylinder block (where the high-pressure pump is located). So, either the rear side passenger cylinder, or the pump.

The valve adjustment on this engines cost thousands dollars (at least, this is how much the dealer wants). I hope this is not the valves, but I really do not know.

(edited)
 

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Kinda sounds like a timing belt tensioner.
 

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Discussion Starter · #3 ·
CatFuzz said:
Kinda sounds like a timing belt tensioner.
It's been that same way for 40K miles. If that would be the tensioner - would it be possible ? Would not it break or else ?
 

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Discussion Starter · #4 ·
CatFuzz said:
Kinda sounds like a timing belt tensioner.
You actually may be right, I found these link:

 

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Does the sound go away with RPM changes?
 

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Discussion Starter · #6 ·
CatFuzz said:
Does the sound go away with RPM changes?
It changes consistently with RPM, and in higher RPM it is getting frequent and the sounds merges with the sound of engine and I do not hear it after 2000 or 2500 RPM.
 

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Discussion Starter · #7 ·
For a comparison - a somewhat similar noise from a Isuzu Crosswind XUVi (2004) 2.5-liter turbo direct-injection 4JA1-L diesel engine:

 

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holger said:
http://youtu.be/zEKdqV36fy8


The engine has been this way since new, and the salesman told me that this is normal, but now I am having some doubts. The noise frequency is approximately 1/4 or 1/6 (one-quarter or one sixs) of the engine RPM. It either means that one single cylinder valves are not adjusted properly, or this is the noise of the direct injection pump (that pumps the fuel once per engine cycle, as far as I understand, and this also would be 1/4 of RPM). The noise is coming from the rear passenger cylinder block (where the high-pressure pump is located). So, either the rear side passenger cylinder, or the pump.

The valve adjustment on this engines cost thousands dollars (at least, this is how much the dealer wants). I hope this is not the valves, but I really do not know.

(edited)
Holger, sorry for the delay in posting. It has been a crazy week. I listened to your recording and the noise you hear is much louder than any individual sound coming from my engine. Unfortunately I don't know what the sound is. I see that others mentioned the timing tensioner but I don't know. I do hear a similar noise but it is much, much quieter and barely audible over the sound of the engine and fan. Sorry I don't know what we are hearing, but it is definitely different from me
 

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Discussion Starter · #9 ·
blackrodeo said:
I see that others mentioned the timing tensioner but I don't know. I do hear a similar noise but it is much, much quieter and barely audible over the sound of the engine and fan. Sorry I don't know what we are hearing, but it is definitely different from me
Thanks for the reply. I actually asked yesterday my fellow mechanic to investigate the matter. Today he called me and told me that this is definitely the valves noise. The gap is too large, he told me, and this is why the sound. He also said that the valve adjustment on these engines are insanely complex - you have to purchase special parts from Isuzu, take off the engine head (10.5 work hours alone), send it to a machine shop, etc. That would be thousands of dollars. He suggested that the best option would be just ignore the sound and use it as-is - he is saying that this is safe and does not affect the performance, at least noticeably.
 

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I'm not sure about your sound/solution, but I tell you that is an UCKING FUGLY tick tick tock tock $clunk $clunk$clunk..............

My 3.5 2004 Rodeo sounds NOTHING like that.

keep us posted!

doubt if that is valve train, way too deep in tone, a clunk clunk verses clatter clatter tick tick, but hard to tell from a youtube video.
 

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holger said:
CatFuzz said:
Does the sound go away with RPM changes?
It changes consistently with RPM, and in higher RPM it is getting frequent and the sounds merges with the sound of engine and I do not hear it after 2000 or 2500 RPM.
Bold is classic symptoms of a bad tensioner.
 

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Discussion Starter · #12 ·
Thanks ! I'll continue the investigation.
 

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Discussion Starter · #13 ·
Big Jay said:
Bold is classic symptoms of a bad tensioner.
I guess that if it would be the tensioner, the sound would be coming from the front of the engine, but it is really coming from the rear of the passenger side block.
 

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Somebody correct me if I'm wrong, but....if it's been making that noise since it was new, and you've questioned the dealer about it, why not take it to them and tell them to fix it? And if they refuse, take them to small claims. Worst case scenario, you lose the filing fee ($40 here in Missouri), best case, the judge is annoyed with the dealer for selling you a lemon and makes him either fix it, or refund your purchase price.
 

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Discussion Starter · #15 ·
Rhodes said:
Somebody correct me if I'm wrong, but....if it's been making that noise since it was new, and you've questioned the dealer about it, why not take it to them and tell them to fix it? And if they refuse, take them to small claims. Worst case scenario, you lose the filing fee ($40 here in Missouri), best case, the judge is annoyed with the dealer for selling you a lemon and makes him either fix it, or refund your purchase price.
I already talked to the dealer. This is what the dealer is saying:

1) There is no proof that there has been the same noise from the beginning. There is no court-approved certified audio record. This is my word against the Isuzu word.
2) The vehicle is under warranty. But it would be difficult to claim the warranty because the vehicle has not been serviced at the dealer shop for the recent 20K miles. I've been changing the oil myself for a while and I have not saved the receipts.
3) Most probable, this is the valve train noise. But the valve train adjustment is not covered by the warranty. This is the most wonderful chapter of the epic story. Isuzu designed a vehicle that requires at least $2000 just to adjust the valves. And Isuzu is not covering the valve adjustment by the warranty, even for the very first 1000 miles. This is an amazing peace of corporate trick "let's screw-up the stupid customer".
4) They want around $150 only for the assessment.

I am still scratching my head over this. My mechanic is telling me "forget the noise, its safe to drive the thing till the first timing belt replacement, then we will think about it". I am driving the vehicle about 8K miles per year, so there is a chance that it will never happen. But I' prefer to drill down to the dirty bottom.
 

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Can someone tell me a little more about this engine? Exactly what it is, and maybe direct me to some photos so I can see what this gentleman's dealing with? Maybe there's some other option. I know when I was screwing around with this Dodge Neon I have (2000 model, 2.0 SOHC), the 4 exhaust rocker arms cost nearly $160 shipped, so I refused to buy them and instead, engineered a set of adjustable rockers for it and it's been running perfectly and quietly ever since. Maybe I can come up with something similar for this one.

I simply can't believe that the only option here is to pay some thief over 2K to adjust the valves on this motor.
 

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Discussion Starter · #18 ·
Sorry, it's been long time since I started this thread. I found time to continue with this issue only today.

I visited the dealer today morning, in San Jose, CA. The guys were polite and they made a free diagnostics for me. They are saying that this is definitely NOT a timing belt tensioner because the sound is coming, as I said before, from the rear passenger side of the engine. If it would be the timing belt tensioner, the sound would be coming from the front engine cover (that covers the timing belt stuff).

They are saying that although the valves are not perfectly set on my vehicle, the noise is not bad and the fuel economy and the performance must not be affected, at least not noticeably. With the valve adjustment price $2000+ it is not worth fixing.

They are saying that one of the reasons why it is so expensive is the timing belt cover construction. You cannot just remove a single cylinder block head; you first have to remove the timing belt cover, which in turn leads to other removals, and so on. Pretty much lots of things to be removed and then re-installed. This is actually the same what my mechanic told me a few months ago.

And no, they are saying that the valve adjustment is not covered by warranty, on any car brand that they know.
 

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When my timing belt tensioner went bad, it had horrible noise, but not above 2200 rpm.

We put it on a lift and an ASE-certified friend listened everywhere with a stethoscope, and the noise resonated toward the back of the block (if not to the tranny).

I was happy that was all the problem was, since it sounded a bit like a rod knock.

Keith
 
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