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California98Civic · 04-21-2018, 11:39 PM

With nearly 260,000 miles on the OEM head gasket from 1998, I suspect a failure has been slowly growing more severe for about a year or more. But I want to be sure. So, I decided to do and document three tests for the head gasket failure I think has happened: (1) for oil in coolant, (2) for exhaust gas in coolant, and (3) for white smoke from the tailpipe.

TEST 1: oil in coolant

Took this blob off the bootom of the radiator cap

Looking into the overflow reservoir

New unused coolant (bright yellowy green)

Used coolant from my reservoir (milky-pale green)

Green coolant droplets sticking to oil on reservoir tube

TEST 2: exhaust gas in coolant

Fresh unused block testing fluid is blue

If combustion gasses are present, it turns yellow

TEST 3: white smoke from tail pipe

Warmed up into the 180s/190s, revving

Spitting water, lol

CONCLUSION: SURPRISE, HEAD GASKET LEAK. BUT NOW I REALLY KNOW. TEST, DON'T GUESS.

P.S. Good news is my wife's 2010 Forester shows no exhaust gas in the coolant at 115,000 miles.

04-21-2018, 11:39 PM	#352 (permalink)
California98Civic Cyborg ECU Join Date: Mar 2011 Location: Coastal Southern California Posts: 6,299 Black and Green - '98 Honda Civic DX Coupe Team Honda 90 day: 66.42 mpg (US) Black and Red - '00 Nashbar Custom built eBike 90 day: 3671.43 mpg (US) Thanks: 2,373 Thanked 2,174 Times in 1,470 Posts	Head gasket diagnosis through testing With nearly 260,000 miles on the OEM head gasket from 1998, I suspect a failure has been slowly growing more severe for about a year or more. But I want to be sure. So, I decided to do and document three tests for the head gasket failure I think has happened: (1) for oil in coolant, (2) for exhaust gas in coolant, and (3) for white smoke from the tailpipe. TEST 1: oil in coolant Took this blob off the bootom of the radiator cap Looking into the overflow reservoir New unused coolant (bright yellowy green) Used coolant from my reservoir (milky-pale green) Green coolant droplets sticking to oil on reservoir tube TEST 2: exhaust gas in coolant Fresh unused block testing fluid is blue If combustion gasses are present, it turns yellow TEST 3: white smoke from tail pipe Warmed up into the 180s/190s, revving Spitting water, lol CONCLUSION: SURPRISE, HEAD GASKET LEAK. BUT NOW I REALLY KNOW. TEST, DON'T GUESS. P.S. Good news is my wife's 2010 Forester shows no exhaust gas in the coolant at 115,000 miles. Attached Thumbnails __________________ See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.