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Coolant loss mystery

694 Views 9 Replies 4 Participants Last post by  24hrsparkey
The other day I noticed my coolant tank was empty when I had a headlight go out. Didn't notice last week when installing an exhaust system. Not to say it had coolant or not. Though I assume I would've noticed. Checked oil. Level seemed normal. (I do testing every other oil change last one a few months ago) fuel economy power seems fine. Added a gal of coolant and marked it with tape. 300 miles later no drop in level. No wet spots on driveway. I replaced water pump last Nov. Any ideas where to check other then hoses? I did have a caliper lose a bolt and vibrate heavy last week as the caliper would dig into wheel upon braking. This was after a short heavy tow in addition.
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Did heavy tow still no coolant loss or discovered leaks. Must have burped an air pocket. Possibly from defroster and/or driving up a 15% grade levee.
There is a chance I'm wrong ,, and Im real glad your truck isn't missing anymore coolant

BUT there is no old fashioned coolant valve or heater valve modulation on these trucks at all . The AIR path is modulated , hot coolant flows full blast all the time thru heater core . Always .
So you running the defrost ( ac kicks on also ) or heater to burp the air is a moog point .
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