For context, I own a 2009 Dodge Journey. About 5 days ago I drove my vehicle to the university I attend and noticed a coolant leak, a bad one. To get back home, I would fill it with coolant and the vehicle guzzled it. I took it to a mechanic shop and he said the lower radiator hose has a leak and he did a pressure test and concluded the freeze plugs are bad (two of them).

Two days later, after topping the car off with coolant (again) I noticed no leak. Could it be my problem is more of a faulty water pump as opposed to freeze plugs? Changing freeze plugs is expensive as you would have to drop the transmission to get to them.

  • Where do you live? If you are in the United States are you aware that Autozone has a coolant tester in their free tool loaner program? Borrow the tool, pressurize your coolant system and then look for leaks (engine off of course.). Suggestion: leaks do not miraculously seal themselves.
    – zipzit
    Commented Jun 17, 2017 at 19:52
  • Yes I realize leaks don't seal themselves, which is why I thought it could be the water pump seal. Heat causes metal components to expand and I figured that as the engine cools again, maybe that alters the seal to cause the leak. Thanks for the advice about Auto Zone, I should stop their on my way back home.
    – Travis
    Commented Jun 17, 2017 at 20:00
  • Yes some leaks can start and stop randomly, If the freeze plugs are leaking, replace them, no other solution, get a second opinion. Corroded freeze plugs are a sign of neglect of the cooling system, replace the freeze plugs and do a full replacement of antifreeze, also add this suppliment...napaonline.com/en/p/FIL4056
    – Moab
    Commented Jun 18, 2017 at 2:21

3 Answers 3


To understand where the leak is coming from, you really need to observe the leak and see what part of the engine/vehicle the leak is happening ... yah, that's sort of round logic, eh? My main point is, you don't say in your question where you observed the coolant coming from, just that it was using a lot of coolant. If it's the radiator hose, so be it. If it actually is the radiator hose, I'd think the mechanic would have tried to replace it for you (at a cost, of course). If it is the water pump, it will usually leak from either a weep hole (or some call it a "pee hole") which will be at the bottom of the casing, or from where the seal shaft if the bushing wears out where the impeller shaft goes through the casing.

It could possibly be the water pump, but realize the pump and the freeze plugs are in very different parts of the engine (in most cases). What we call freeze plugs are actually core plugs, meaning they are holes left in the block during casting where the sand core is held in place to allow for a proper flow of molten metal. They double as freeze plugs because it's convenient to have them there and it works. You shouldn't need freeze plugs up by the water pump because you already have holes there which are plugged by the water pump and serve the same core plug purpose.

Something about mechanical things is, they don't usually fix themselves (Note: I put usually because I hate to use absolutes like always or never ... in this case I'm tempted). Leaks just don't quit leaking (in almost ALL cases). Broken things don't magically heal. A coolant leak may stop leaking, but you can be sure it will be back, bad as ever when it decides to do it ... and most likely it will be at a time when it will be completely inconvenient to you, have no doubt (think: Murphey).

  • Thank you for your explanation I learned a few things. I'm sorry if my explanation sounds silly, but at the risk of sounding silly to a costly repair, the choice was obvious. I'm sure Murphey will penalized me in the future.
    – Travis
    Commented Jun 17, 2017 at 19:19
  • @Travis - Sorry if what I wrote makes you sound silly ... I really didn't mean it that way. Things do happen, including a leak which stops. I'm just saying look out because it will be back and probably with a vengeance! :o) Commented Jun 17, 2017 at 19:21

A water pump can leak and never show a drip. At some engine speed it drips onto the fan which disperses the coolant. I had a car you could drive for hours at 40 - no problem ; but over 55 it leaked very badly with no trace. Freeze plugs are only to get the core sand out of the block after casting ; the freeze plug story is just some clever PR. I haven't had a freeze plug problem for 40 years after I got rid of my last Chrysler products.


If it's a very small leak, I guess its possible that rust and scale could be drawn to the leak and eventually plug it. Kind of like the engines own stop leak.

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