robp823 Posted January 11, 2013 Share Posted January 11, 2013 I have another C15 that were having issues with.One of the drivers checked the coolant today and said it was black.When i checked it out it was indeed black but not oil.It appears to have soot in the coolant.Could this be a head gasket???Installed a combustion leak detector and results were positive for combustion gas in the cooling system.Just wandering if anyone has any experience with these engines if there is a known concern for this??Maybe cracked head??.Truck has 320,000.Engine serial is a MXS.Maybe Dieseldoc can chime in. Quote Link to comment Share on other sites More sharing options...
dieseldoc Posted January 13, 2013 Share Posted January 13, 2013 I have not seen the coolant turn black before from a head gasket, but anything is possible. However if the gasket is blown and it made its way to a water grommet I could see this happening. C15 heads dont typically crack, but it happens. If you dont see anything obvious I would definitely have it pressure tested. Is it pushing coolant out the overflow? Is it smoking white at start up or while running? Any other symptoms, or just noticed the black coolant one day? If the head gasket is blown I would highly suggest removing the liners and checking the counterbores for wear and the liner flange thickness. It was required for us to do this on jobs that were warranty. Quote Link to comment Share on other sites More sharing options...
robp823 Posted January 13, 2013 Author Share Posted January 13, 2013 Thank you for the advise so far.Its not pushing coolant and there is no smoke.The driver just noticed it when he checked it the other day.I did not pressure test the system yet.I did however use a combustion leak detector to check for the presence of combustion in the cooling system and it turned out positive.Is it possible the the coolant could have been mixed or broke down over time?Im going to drain the cooling system and flush today. Quote Link to comment Share on other sites More sharing options...
dieseldoc Posted January 14, 2013 Share Posted January 14, 2013 Does the truck have an APU(auxiliary power unit), tied into the engine cooling system that could be contaminating it or putting soot in the coolant?I would think that for their to be a current problem putting combustion/soot in the cooling system, it would need to be also putting pressure in the cooling system as well. It is quite possible that it is contaminated coolant from a previous failure. . . . or a cooling system not cleaned well enough from previous issue. I guess I personally have not seen this happen in CAT powered vehicles. I personally would check for excessive pressure building in the cooling system(bottle test) and if that seems ok, I would flush the cooling system and keep a close eye on it for a while. Perhaps take a coolant sample and see what the lab has to say. Sorry I dont have a better answer for you, but have not run across this before in a cat. Keep me posted though I am very curious as to what you find. Quote Link to comment Share on other sites More sharing options...
robp823 Posted January 14, 2013 Author Share Posted January 14, 2013 Yesterday i did find the precooler leaking.Im going to have to replace that then retest.As for the bottle test i have never done that.How do you perform it?I did flush the system yesterday multiple times until only pure water came out.I filled it back up with water again and im going to check it when the driver gets back today. Quote Link to comment Share on other sites More sharing options...
dieseldoc Posted January 15, 2013 Share Posted January 15, 2013 The "bottle test": we took a radiator cap and took the guts out of it and installed a fitting in it. Hooked a hose to it and got a clear 1 gallon jug(washer fluid bottle works well). Put the hose from the modified radiator cap into the jug. Once the engine is at operating temp the bubbles should slow significantly and be intermittent. If the bubbles are steady than it is highly probable you have a head gasket(typically cylinder head, but could be air compressor) or cylinder head issue, or pre-cooler in the case of ACERT engines. It is best to do this test under load, we had a chassis dyno at my dealer. However you can do it while driving the truck and having somebody watch the bottle. Not scientific by any means but was quite effective and about 90% correct. With your truck not pushing coolant I am leaning more toward a poor flush job from a previous failure. Quote Link to comment Share on other sites More sharing options...
dieseldoc Posted January 17, 2013 Share Posted January 17, 2013 In my previous post I explained the bottle test and said to take the guts out of a radiator cap to adapt the radiator to a hose and finally into the jug of water. In thinking of how I worded that, I saw how it could have been interpreted or misinterpreted that is. You want to be sure it will seal to the radiator, so as not to lose "pressure" out the overflow tube on the radiator. If you are losing "pressure" out the overflow tube and all of it is not going to the water jug you may get faulty results in your test. I had a cooling system pressure tester that the pump crapped out in, So i removed the pump from the tool and used that cap set up as my test tool. Quote Link to comment Share on other sites More sharing options...
Aaron Posted January 18, 2013 Share Posted January 18, 2013 I saw a guy condemn a head gasket using this at work, but he didn't wait until the engine was hot first. It had a head gasket put in it at the International store, and is now pushing coolant out of the overflow again, about two weeks later. It builds 10-15psi cooling system pressure idling in about two minutes, I can't imagine what it does under load. Quote Link to comment Share on other sites More sharing options...
dieseldoc Posted January 19, 2013 Share Posted January 19, 2013 I too have seen people try to use this test and not let the truck get to operating temp first. Lack of fully understanding the engine systems and how they work or the most likely reason is in too much of a hurry. You gotta love flat rate and how it dictates diagnostics and repairs for some people. I am paid hourly where I am but get and efficiency bonus, However even on my best month have not seen a check. I have just written the whole bonus program off and work as if I am just paid hourly. Quote Link to comment Share on other sites More sharing options...
robp823 Posted February 3, 2013 Author Share Posted February 3, 2013 Well we found the problem with this one.I pulled all 6 injectors and injector cups.The bottom injector o-ring on all 6 injectors that seals off the combustion chamber was gone.Also the bottom o-ring on all 6 injector cups was pretty much gone on all of them as well.Re o-ringed cups and injectors.Been running the truck for 2 weeks.No more black coolant.Thanks for the help guys. Quote Link to comment Share on other sites More sharing options...
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