Soot in degas tank?

MeTo

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I have 480 miles on my rebuilt 7.3 and I think I have soot in the degas tank now. The coolant level is fluctuating more than usual also. I don't see any oil. I rolled up a piece of paper towel and stuck it in their, all red Cat ELC. So it looks like a copper washer (seal) on the bottom of one of the injectors is leaking? I disconnected the small hose from the top of the degas tank, which comes from the radiator and stuck it in a cup of water. I had the engine idling and at temp. NO BUBBLES. I can't believe this.

I had the machinist install new cups with Loctite 620 and pressure test the heads when they got rebuilt. I was meticulous when I installed the injectors. My procedure was as follows; remove o-rings/copper seal and clean injectors and nozzles, lube and install RiffRaff o-rings & copper washers, insert into cup, tap to seat injector with rubber mallet, torque, another tap and another finale torque. The torque changed on a couple injectors, so I tapped and retorqued until it didn't.

What now? Of course last night we got new snow on the ground here NE Wisconsin. My truck is too tall to get in my shed. So, I'm going to have a shop do it. Has anyone done a vacuum test on their coolant system? I don't think a pressure test would be a good idea? That would risk hydro locking a cylinder. Can the coolant be tested for soot? If so, who?

The leak appears to happen only when the engine is under higher loads? All appears to be normal if I just take a gingerly drive. I'm apprehensive to give it an acid test in a hot tune. I would like to be able to drive it to the shop.

No coolant in oil and oil level doesn't change.

Thoughts or recommendations?
 
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DEEZUZ

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Did you perform a coolant flush after rebuild? It may be some crap left over from machine work?
 

MeTo

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No I did not. I figured the engine was clean from being cooked, all hoses were replaced with new gates, new water pump and a new thermostat. I didn't think of cleaning the radiator inside (the outside got a good cleaning) and the heater core. Crap! That still dosen't explaining my coolant level fluctuating as much as it does, at least a quart or more.
 

DEEZUZ

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Also, I'd get a combustion test done. I don't think you have combustion though.
 

DEEZUZ

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Also, the combustion would be leaking around the bottom of the cup, not through copper seal/injector. Also I'd expect hydro locking when engine wasn't running.
 

MeTo

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Thanks for the info, much appreciated. I revisited a cross section schematic of the cup area in the head. I think you are right? Two guys I talked to locally, both suspected an injector copper washer. I'm going to do some more test drives and see what develops? Could it be possible it is just residual contaminates and the coolant system "burping" trapped air?
 

MeTo

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Well , it turned out to be a big burp and rubber residue/particles from replacing all the hoses and NOT cleaning them before the install. Another lesson learned.
 

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