12 Valve 2nd Gen Dodge Cummins 94-98 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps

Looking at buying a 98 12v--lots of blue smoke

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Old Dec 20, 2010 | 07:36 PM
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racecar's Avatar
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Default Looking at buying a 98 12v--lots of blue smoke

Hi, I was hoping someone could give me some insight on what is wrong with a truck i looked at buying, 1998 12v 4x4, automatic 3500 series with dump box. Smokes a lot of blue smoke, even after warmed up, if you floor it sitting still it rev right up, but if you try to drive it the truck has no power. What could it be or a combination of things? Input would be greatly appreciated. The odometer reads 75,000 miles, and it has been sitting for about 6 mths.

Thanks
 
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Old Dec 20, 2010 | 08:04 PM
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blue smoke is usually burning oil. probably has no power because it has no compression anymore. does it start well? and also where it has been sitting possibly the rings have siezed some and just need to be freed up, i don't know if diesels work this way but the gassers do this sometimes and if you put cheap oil in and run it pretty hard you sometimes get lucky and free them up.
 
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Old Dec 20, 2010 | 08:17 PM
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Thanks, the motor started right up with no hesitation. It almost sounds like it is missing when you give it throttle when it is running.
 
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Old Dec 20, 2010 | 08:24 PM
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if you smell the exhaust does it smell like oil or fuel? if it smells like fuel it could just be a case of slipped timing
 
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Old Dec 20, 2010 | 08:34 PM
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It was hard to tell if it was fuel oil or engine oil, but as a guess I would say it was fuel oil.
 
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Old Dec 20, 2010 | 09:00 PM
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Could be as simple as a bad turbo, injector, or as bad as a burnt piston. Couple quick checks, pull the dipstick, does the oil smell like diesel fuel? That means fuel is getting past the rings. Rev the motor with the dipstick out, if oil blows out, major internal problems. If the price is right, and it's in good shape, go for it. If the motor has a major problem, figure $3-4k to rebuild, you'll probably put at least that much into the trans. Plus another $1k or so into the front end. Figure that into what you're willing to spend. Don't forget labor, if you can' do it yourself.
 
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Old Dec 20, 2010 | 09:30 PM
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Originally Posted by turbostang7
blue smoke is usually burning oil. probably has no power because it has no compression anymore. does it start well? and also where it has been sitting possibly the rings have siezed some and just need to be freed up, i don't know if diesels work this way but the gassers do this sometimes and if you put cheap oil in and run it pretty hard you sometimes get lucky and free them up.
I think turbostang7 is correct
 
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Old Dec 20, 2010 | 10:27 PM
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we got a f550 dump and a louisville dump that both were blowing blue smoke and the louisville was a bad turbo... swapped turbo and issue was resolved... f550 was bad injectors... i would be willing to bet compression tests come back good... i would def compression test it before u hand over any money!
 
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Old Dec 21, 2010 | 09:17 PM
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2200 to fully rebuild the motor with mahl pistons rings bearings and seals top to bottom, lifters and cam with machine work if you do the work yourself did it last year to mine
 
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Old Dec 22, 2010 | 08:42 PM
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My buddy is rebuilding his for about 800 all he had done was the block work. Dont know what else hes doing to it he is rebuilding it himself
 
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