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coolant gone, black sludge on radiator cap.

Old 12-06-2014, 02:57 AM
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Join Date: Oct 2014
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Default coolant gone, black sludge on radiator cap.

I've posted on here before about a 97 accord and some difficulties I have had. One day when I tried to start it, it hesitated for a split second, and then started. This happened quite a few times, and it started happening a few weeks after the starter was replaced. I then checked the coolant and oil...but all my coolant was gone. Wasn't on the driveway, and there was a lot of pressure built up when I took off the radiator cap (bled the system more than a handful of times since I have had it). The (also new) cap had black sludge on it, almost looked like used coffee grounds. I'm at a loss with this car as my compression was 120 across the board (a few have said that is pretty low) and a combustion test where the fluid didn't turn yellow. It was a royal blue, and turned a slighter blue color. I put it to the exhaust and alas, it turned yellow. My brand new spark plugs were corroded within a few months also. Do you think i'm dealing with a dreaded head gasket issue, or maybe an intake manifold gasket issue? Also, I live in Georgia so our weather fluctuates from warm to cold during the fall/winter time. My oil cap had a lighter brownish color, but I've heard that to be completely normal due to condensation. (My actual oil looks perfectly fine). I know I'm leaking/burning coolant somewhere, anyone else have this problem?

Last edited by mra3; 12-06-2014 at 03:01 AM.
Old 12-06-2014, 07:35 AM
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Location: Katy, TX
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If you're losing coolant steadily, it's going somewhere. Suggest performing a cold pressure test of coolant system to see if leak is external or internal. If an internal leak, then head gasket is likely.

good luck
Old 12-07-2014, 09:02 PM
Join Date: Dec 2014
Location: Pittsburgh
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i say head gasket given the symptoms. luckily these ones are not TOO difficult to do.
Old 02-01-2015, 04:34 AM
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Okay, I am back! Pressure test was done. There was a visible external leak and it was fixed. Currently still trying to bleed the system completely, and putting the full capacity of coolant in. I am having another problem that I was having when I first got the car. I am actually showing a code for a cylinder 3 misfire (went away when I changed spark plugs the first time.) My spark plugs are once again, completely corroded, and 3&4 were soaked with gas. My question: Have any of you dealt with a fuel injected car completely flooding itself out? It has been totally fine these past few weeks until this morning, with minor stalls in cranking, which I just attributed to needing a new battery as the one that came with my car is way too small for my engine, and my starter is replaced. Got the cylinders cleaned out, put new spark plugs in, and it fired just fine. The injectors are also all ticking at the same frequency and tone. I am just at my wits end with this car..

Old 02-01-2015, 09:12 AM
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Super Moderator : And A Texan
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Location: Katy, TX
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Injectors will sometimes fail to completely close allowing fuel to leak. This can cause starting problems and higher fuel consumption. Diagnosis requires performing a injector balance test (how much pressure lost when injector is fired for a few secs) to see if injectors are closely balanced (very similar pressure loss) and are capable of holding pressure. This is a rare problem based on posts we see on the forum.

Did you confirm that all coolant leaks were repaired by repeating the cold pressure test? One leak could mask a second leak.

Plug fouling could be due to oil (carbon buildup is typical). A compression tet may be in order to check system condition.

good luck
Old 02-01-2015, 11:37 AM
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Those plugs do not look gas fouled or oil fouled. Additives in gas can discolor the plugs, suggest you recheck everything up to this point, replace the plugs if it bothers you. You need to find the source of the black sludge,,sounds like a head gasket to me.
Old 02-02-2015, 11:23 AM
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Don't forget to rule out a ruptured fuel-pressure regulator.

Any gasoline in the vacuum hose for the FPR?
Old 02-03-2015, 07:25 AM
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Posts: 595

And add to that the injector resistor.
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