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Why are some Dmaxes quiet and some not???

2514 Views 12 Replies 9 Participants Last post by  Duramax Dually
I've been wondering about this for quite some time, but there was another topic recently about fuel additives that made me think about it. That topic said that some fuel condiitioners could reduce valve train noise. I had NOT been running any fuel conditioner in the summer, just in the winter (mostly for gelling purposes).

My truck has had the "tick" until about the last 2000 miles, and now it IS getting quieter. We have a Dmax at work, and it's signifigantly quieter than mine, and always has been, even when it was new. I've actually heard 6.5L's that are quieter than my truck.

With my last fill up, I added some PowerService Cetane booster/conditioner (it was available at WalMart, and I thought that it couldn't/shouldn't hurt). Now, I've noticed that the drivers side or my truck is MUCH quieter than it ever was (the side that used to tick), but the passenger side is much noisier than normal.

My question is really this. What is it that makes some engines quite a bit quieter than others, not including the tick? It's not really something that I'm concerned about because I had a Cummin(g)s
before this, and I'm used to a little noise
. With a Cummins, it was impossible to tell a quiet one from a loud one, because there's no such thing as a quiet Cummins before '03.

It's just one of those big mysteries of life that makes you go Hummmmmm...

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Georgecls said:
... The combination of the increased cetane (delayed ignition) and burn modification combine to increase the power of the combustion cycle and also increases fuel efficiency.

While I'll tend to agree with this statement, there's still more to the noise thing than just fuel. The cetane booster that I used on the last tank DID improve my fuel economy, so I know that it does help.

But, here at work, our Dmax gets fueled with WHATEVER is on the road or close. They don't stop at truck stops, they just get diesel whereever they can. There's NO possible way that the quality of the fuel in our work trucks is anywhere close to anything acceptable.

I however, ALWAYS buy my fuel from the local truck stop. I DO get better fuel economy with this fuel, so I know that it's of better quality than buying it just anywhere.

Even with the "good/better" fuel that I'm putting in my truck, my truck is STILL signifigantly louder than the ones here at work. There just seems to be a wide range of noise that comes from these engines, and I can't believe that it's all fuel related.


PS: I do NOT have Juice or any box. I'm totally stock, and so are the work trucks.
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a64pilot said:
... My truck is getting noticably louder as it ages.

The problem with my truck is that it ONLY has 13,000 miles (just turned last nite), and when it had the "tick", I couldn't tell how loud it really was. Now that it's gone, it seems louder than I have heard others.

Mine is a late production 02, so I'm pretty sure that I have the new design hardened injectors...

a64pilot said:
... a sure sign that the injectors were getting dirty, like a varnish build up, was they would get noiser. ... Why couldn't dirty/ going bad high pressure injectors do the same? ...

That kind of makes me wonder if I don't have an injector going out on the RIGHT side of my engine since it's noticeably louder than my left side.

That's something that I never thought of.

I bet that I would have to pull my dealers teeth to get them to do a balance check. While my dealer is really good about warranty work, they are NOT keen on checking things that I MAY think are wrong. They kind of have the wait and see attitude. I asked them once about making sure that my truck had all of the latest flashes on the TCM and ECM, and they said that they wouldn't do any of that unless there was some problem.

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