losing coolant - Diesel Forum - TheDieselStop.com
6.4L Power Stroke Engine and Drivetrain Discussion of the 6.4L Power Stroke diesel engine and drivetrain in the 2008-Up Super Duty trucks. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 6.4L Power Stroke engine.

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post #1 of 6 (permalink) Old 11-19-2012, 02:36 PM Thread Starter
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losing coolant

I have been losing coolant for about 4 years now. It comes from the cap on the degas bottle, bout once a month i put about 2 qts in it. Ive replaced the cap and it still does it. Does anybody know what could be causing it. Ive read all over about radiator leaks and hose leaks and orings but I have had none of these leak. It only comes from the cap. Ive tested the air in the degas bottle for diesel exhaust with a blue point test kit and its been negative everytime. I bought this truck new in 4/2007. Its a job 1 and I did the venturi hose kit when it first came out and Im still running with original radiator. I have 61k miles. Any help is appreciated. Thx

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post #2 of 6 (permalink) Old 11-19-2012, 03:49 PM
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Head gaskets leaking/head studs stretching.
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post #3 of 6 (permalink) Old 11-19-2012, 04:13 PM
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2nd that. Could also be EGR cooler.
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post #4 of 6 (permalink) Old 11-19-2012, 05:07 PM
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No exhaust gases in the degas bottle. Not a headgasket issue.

Look at EGR valve and coolers. If you have the old style EGR valve I would bet that is it.

Coolers with that amount of loss would have been a bunch of white smoke I'd imagine.

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post #5 of 6 (permalink) Old 11-19-2012, 06:38 PM
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Generally when you have puking back through the Degas bottle it means that you have a clogged oil cooler. If you are using Ford Premium yellow silicate coolant junk or other silicate coolant, it is prone to cause the silicate to gel thus clogging the coolant pores of the oil cooler. With the inability of the proper amount of coolant to flow through the oil cooler (heat Exchanger) the oil becomes hotter than it should thus the oil cooler is hotter than it should be. Because it is hotter and the coolant flow is less, the amount of heat transferred to the coolant will cause it to flash boil and puke the superheated coolant back through the degas bottle and overpressurizing the 16 pound cap. That will produce the white stuff you see around the degas cap and bottle.

You can try to back flush the oil cooler using Restore to disolve the silicate gel. It may help but it may also completely clog the oil cooler further thus causing the needed replacement even sooner.

I just replaced mine myself as well as the EGR cooler.

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post #6 of 6 (permalink) Old 11-20-2012, 05:04 AM
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I was losing cooolant for 3 years turned out to be headgaskets. Have the pressure checked in the degas bottle. Mine was through the roof. You will also see white spots around the bottle.
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