Decoking pistons and rings ? - Diesel Forum -
7.3L IDI Diesels (Not Power Strokes) Technical discussion of topics related to vehicles powered by the 7.3 Liter In-Direct Injection Navistar engines.

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post #1 of 4 (permalink) Old 04-12-2006, 05:53 AM Thread Starter
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Decoking pistons and rings ?

I have heard from someone off this form that it is a good idea to periodically pull the glow plugs or injectors and do a long soak of combustion chamber ( > 12 hr ) with a couple ounces of ATF or Marvel Mystery oil to de-coke the piston rings and lands. After the soak is done the engine has to be turned over a good bit drive out the liquid before reinstalling the glowpugs (or injectors) to prevent hydrolock . The engine should be run for a few minutes then the oil changed to get the solvents out .

Anyone familiar with this procedure ? Does it help ? - Thanks
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post #2 of 4 (permalink) Old 04-13-2006, 07:46 AM
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Re: Decoking pistons and rings ?

I have not heard of a specific proceedure, but I found Mercury Power Tune (boat stuff) will remove coking on pistons and cylinder tops. It sure did when I had the heads off last. Your proceedure mentioned and MPT may work too. Contact a Seafoam rep and get some advice there too. I questioned our local rep and got some impressive answers on several products I did not know they even had.

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post #3 of 4 (permalink) Old 04-13-2006, 08:03 AM
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Re: Decoking pistons and rings ?

I wouldn't bother, the chances of breaking a big chunk loose and scoring a cylinder wall outweigh any questionable benefit. If carbon gets too thick it will burn off of its own accord. I've had these engines apart before and it's not like there is some place where the carbon continues to build up. They can go 300,000 miles without ever being touched if nothing breaks along the way....

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post #4 of 4 (permalink) Old 04-13-2006, 09:05 AM
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Re: Decoking pistons and rings ?

as birk said--also--if wanted to do it the right way--put on water injection--like a mini steam cleaner inside the engine--just dont dump tons like argve did!!!!!!!!!!!! this will slowly clean out any deposits--and keep them out--

94 f250 idi turbo sc e4od alum fac rims 149,289 --dana 60 frt with posi--10.25 rear w/posi--shouldnt get stuck!! ats turbo 3" parts on--what a diff from stock turbo!!!!!--- also 96 F250 with 305,000 is fixed!!-- 7.3 rattler-also 85 6.9-needs new engine!! tired!!
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