How reliable is the cummings 5.9?
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The black smoke is normal in the bottom of a gear like that (low rpms), the motor is running high boost and high load but can't quite catch up fast enough so the black smoke results.
Well there is a good reason why I want a 98 12V and not a 24V.
However I'd say that this would be biased since we are in the 12V forum, I bet there are 24Vs out there doing it they are just a bit fewer and further between. I think the motor itself is as rugged but the fuel system, well that is another story.... 
Well there is a good reason why I want a 98 12V and not a 24V.
However I'd say that this would be biased since we are in the 12V forum, I bet there are 24Vs out there doing it they are just a bit fewer and further between. I think the motor itself is as rugged but the fuel system, well that is another story....
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Joined: Oct 2002
Posts: 509
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From: Desert Northwest (Pasco WA)
Smoke
Doogie & Matador,
do you guys run fuel additives at all? I noticed mine smoked gray some at idle, and blue smoke in the morning even if it's 75 when I leave for work.
I put an extra dose of Amalgamated diesel additive in a couple tanks and drove it kinda hard to boot. Smoke has cleared up a lot. Might get something like Stanadyne or Howes and run a few tanks with that. What I did was wait until I was down to 1/4 tank then put enough in for 3 tanks to give it a concentrated dose. Seems to have worked. The original injectors & pump are working quite well at 352k.
Vaughn
do you guys run fuel additives at all? I noticed mine smoked gray some at idle, and blue smoke in the morning even if it's 75 when I leave for work.
I put an extra dose of Amalgamated diesel additive in a couple tanks and drove it kinda hard to boot. Smoke has cleared up a lot. Might get something like Stanadyne or Howes and run a few tanks with that. What I did was wait until I was down to 1/4 tank then put enough in for 3 tanks to give it a concentrated dose. Seems to have worked. The original injectors & pump are working quite well at 352k.
Vaughn
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I've found using higher cetane fuels reduce the amount of grey smoke, so I guess you could say an additive would also help reduce this. I found when taking my injectors out that they were covered in carbon pretty good, a bit thicker than what I was looking for. I guess that was my warning to stop driving it so softly, diesels love to be ran hard, running them soft will only kill them. I use Redline DFC but it still doesn't seem to help the problem from what I notice, I've tried not using any and using more than enough. No noticeable chance either way, but pour a little WVO in and the cetane boost is visible in the lack of smoke and audible in the almost gasser like sound.
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Joined: Nov 2001
Posts: 4,199
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From: Branchville, Alabama
Originally posted by infidel
Notice that these trouble free high miles are all on 12 valves. I've personally never seen a 24 valve break 300k without major repairs.
Notice that these trouble free high miles are all on 12 valves. I've personally never seen a 24 valve break 300k without major repairs.
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Joined: Mar 2004
Posts: 150
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From: NJ
i traded a 99 ford diesel for a 96 12valve cummins and it was the best thing i ever did. i bought it 5 months ago with about 100k miles on it and it runs great. i floor it where ever i go. i tow race cars and other stuff. you can't kill that motor. when you buy it make sure you use mobil delvac 1300. great oil. i have 12,000 miles on that oil and it is still as good as the day i put it in.
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Joined: Apr 2004
Posts: 126
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From: North Dakota
MacKenzie
I do run Stanadyne or Power Service additive in the winter here in ND. I replaced the injectors about 10000 miles ago. I havent run additives for probably 15 thousand miles or so. Maybe I should add some and see what happens.
I notice mine smoke seems to be a lot more blue than black sometimes in the morn but then clears up after that and it doesnt do it on a regular basis.
I do run Stanadyne or Power Service additive in the winter here in ND. I replaced the injectors about 10000 miles ago. I havent run additives for probably 15 thousand miles or so. Maybe I should add some and see what happens.
I notice mine smoke seems to be a lot more blue than black sometimes in the morn but then clears up after that and it doesnt do it on a regular basis.
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Joined: Dec 2003
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From: north cali
Vaughn i haven't used any additives, i plan to use something to clean the injectors. mine smokes but only when i give it wot. in the last months i have been getting more smoke at startup but thats it. chris
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