Fuel in radiator with a 6NZ - Diesel Truck Forum - TheDieselGarage.com
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post #1 of 5 (permalink) Old 07-01-2016, 04:06 PM Thread Starter
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Fuel in radiator with a 6NZ

I'm getting fuel in the radiator tank with a 6NZ in it. I read somewhere that it can be from the injectors. But I can't remember, is it the cup seals or the injectors seals? Is that the only way that diesel can get into the antifreeze?
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post #2 of 5 (permalink) Old 07-01-2016, 05:22 PM
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I think a cracked cup can do that as well.
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post #3 of 5 (permalink) Old 07-02-2016, 01:44 AM
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Injector Cups

I know it's not an old Cummins but they would do that with a cracked injector sleeve. Cummings had the tooling to test and replace the sleeve without pulling the head. They could have it in and out for less money than I could put a recon head on, that only covered two cylinders, myself. You might call Cat and ask. Some of the best money you ever spend could be at a good Cat house.
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post #4 of 5 (permalink) Old 07-02-2016, 08:59 AM
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Pull all 6 injectors, drain antifreeze, borrow the cup puller tool from a cat guy and pull all the cups, almost guarentee one or more is leaking around hardened up orings and or one is cracked. Id replace them all for all they cost, like $10-14ea. Get new injector holdown bolts and orings to. Use siliglide on cup orings and clean motor oil on injector orings. Flush your coolant system with a good heavyduty coolant system flush and be prepared to blow some radiator hoses and heater hoses if its had fuel in the coolant system long or save yourself the headache and possible motor job from overheating from blowing hoses and change all the radiator hoses now. Up to you. Good luck.

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post #5 of 5 (permalink) Old 07-04-2016, 11:36 PM
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You, most certainly have at least one bad injector sleeve. Be sure to note, when you pull the injectors, as to whether there is carbon built up on the outside of the injector. When the injector seats go bad, this allows hot combustion gasses to flow up between the injector and the sleeve. This causes the injector sleeve seals to fail prematurely. I have even seen injector sleeves break off in the head, due to deterioration of the metal, from all of the heat. (Note:I have a tool to remove the broken piece, without pulling the head, if that should happen.) Injector seats can be repaired, while the head is still installed on the engine. Cat will tell you, that you need to replace the head if the injector seats are bad. Not so!
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