Will the hose leak coolant with the heater off?

Had a coolant leak in my car for a couple of weeks but couldnt find it from looking in the bay.

Yesterday, i decided to put the car on stands and look up from underneath and i found  hidden way behind between the engine and firewall...dripping out right where the heater hose clamps onto the engine. Very hard to see. I had to use a mirror to look at it properly.

So following the droplet lines im pretty sure thats the place its leaking from. But i never use my heater so  shouldnt the heater core valve stay shut... why would it leak from there

6 Answers

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  • Anonymous
    2 months ago

    Replace the hose.  Service and bleed the coolant.

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  • 2 months ago

    If the hose leaks, the hose leaks and it won't matter if the heater is on or not. Fix the hose.

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  • 2 months ago

    There is no heater valve on most vehicles. The coolant always circulates through the heater core.

    The temperature in the passenger compartment is controlled by blend doors in the heater box.

    Source(s): Mitsubishi Master Tech
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  • 2 months ago

    It could be leaking from the heater core valve

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  • JetDoc
    Lv 7
    2 months ago

    Just because you're not using your heater doesn't mean there's no coolant flowing through it. If you can see coolant dripping from the end of a hose try tightening the clamp.

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  • 2 months ago

    There is still pressure on the system whether you utilize the heater or not, so like having AC in the cold, you have to cycle it now and then (and the AC also dries air). So, cycle the system now and then, but more important is if the hose clamp just needs tightening or if it needs replacing or you have a secondary issue. Drain the system enough so you can clear the hose issue; if it's time to do a coolant/antifreeze swap all the better, if not just drain into a CLEAN container and add back later. 

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