#general advice wanted - boiling coolant

6 messages · Page 1 of 1 (latest)

light quest
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running a 2.0 duratec-pet (pretty sure the later model for this car) - yes the ones that like to run hot
ferd mondy mk3 - pretty sure it shares 95% with the focus
pretty sure i just need to do a coolant flush, clean and then a refill but wanting a second opinion before i go and dump another bottle of coolant in for like the 5th time this year - backstory possibly needed/possibly fixed - thermostat opens at 106c/223f the same time the fans come on, during normal driving it doesnt really go over 80c/175f, after making sure everything is working properly after possibly fixing my original issue coolant likes to boil around the the same temp as when thermostat opens. yes i could just drain a little and then refill with same concentrate but for what ever reason my that concentrate/premix is no longer in stores so i got a named brand of a different color that has a slightly higher boil and lower freeze temp. video is about 30 seconds after i shut off car and boiling kept going after a little after video stopped. there was a little boiling action with res cap off but mostly settled down when cap was on fully or with a little throttle .

  • backstory. kept getting air in cooling system then found out that the return/purge hose from thermostat to res tank had a fairly big physical blockage in it, replaced the hose and now coolant level stays more consistent and doesn't want to overflow like crazy every 5 minutes and cooling power seems to be more efficient and it now no longer has a bunch of bubbles going through after about 20 minutes of running.
lost peak
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Does the coolant boil smell like exhaust?

sharp plover
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@light quest I always raise an eyebrow when someone says 'possibly fixed -'... ?????????
You also mention 2 thermostats? The 180f should be standard, Where does the 223f come from?
As for boiling, have you replaced your radiator cap?

light quest
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The 223 is when it fully opens and the average coolant temp when monitoring through obd I would say due to airflow stays around the 180 mark and I've been switching between 3 different caps, the reason why I say I may have fixed it is due to removing a a chunk of crud from the return line from thermo to reservoir as it was fully blocked and wasn't letting anything through

elder garden
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The proper fix is likely: brand new thermostat, brand new radiator cap, drain and replace the coolant. The only question mark is if exhaust gasses are getting into the coolant - if so, there’s more work to be done.

lethal island
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223 would mean a 200 thermostat, which is high, 190 is the max I have seen