[Matthew Gubler]

I noticed my car has been leaking small amounts of coolant, Ive had it pressure tested and they said everything check out.

The other morning after running the heater on my way to work I noticed it leaking quite a bit of coolant after I parked my car. I looked underneath to check it out and there was coolant on the cooler lines on the opposite side of the oil filter and also noticed coolant dripping from the weep hole.

When I run my car without the Heater on there is a lot less coolant leaking.

I am curious if this is a water pump issue or maybe problems with the Heater core lines?

If it is leaking coolant through the weeping hole is it for sure the Water pump?

Any comments or links to more info is very appreciated.

Thank you.

 

[Glennda5id]

Coolant is always flowing through heater core so running the heat shouldn't make a difference.

You need to dry everything and then watch it as it leaks and chase the leak. Leaks can be tricky if you have been driving as the leak can blow around and get over other parts. Best to check when not moving.

There is a black metal coolant pipe that starts close to the lower rad hose that runs up along the drivers side valve cover to one of heater core hoses. That could be leaking.

I would only expect the water pump to leak when the water pump is spinning.

 

[subiesailor]

Coolant is always flowing through heater core so running the heat shouldn't make a difference.

You need to dry everything and then watch it as it leaks and chase the leak. Leaks can be tricky if you have been driving as the leak can blow around and get over other parts. Best to check when not moving.

There is a black metal coolant pipe that starts close to the lower rad hose that runs up along the drivers side valve cover to one of heater core hoses. That could be leaking.

I would only expect the water pump to leak when the water pump is spinning.

The location ish of his coolant doesn’t quite sound right for the pump either. But air flow while moving will as mentioned blow coolant around and make a mess and be hard to track the source.

 

[gen2lover]

The weep hole in the bottom of the front engine cover is there for one purpose...to alert you that your water pump seal is failing. That said, I would be certain that it's definitely coming from the weep hole, and not running down from the lines, which are prone to rusting and leaking as well. Since the seal is dynamic, it may not leak when the pump is static, hence the passed pressure test.

Changing the water pump is not a fun undertaking. You are pulling the front cover off the engine... oh, all those bolts. You would probably want to change the chain followers while you are in there...etc.

Maybe this is the time to try some Subaru coolant conditioner and say a few prayers.

 

[CNY_Dave]

I had to replace the steel lines on mine... tricksy, the leaks can be.

I don't think I've seen another thread here or elsewhere about a dripping water pump on an H6.

The interesting thing about the weep hole is, not sure they really cared about diagnosis, but an air gap does allow a leak to leak elsewhere than into the oil!

 

[1 Lucky Texan]

only read of one H6 waterpump leaking. It happens but is rare. and yeah, cool that it's designed to leak coolant outwards.

still, it's a sucky job and I might even consider a jdm engine swap before busting into the front of that timing system.

 

[Matthew Gubler]

Update!

I ran my car with the A/C off and with the A/C on and no coolant has leaked.

It only leaks after the heater has been on.

I will check the line that runs to the heater core.

Any other lines I can check that would be related?

Thanks

 

[idosubaru]

Remember we only have words - but so far the word picture is confusing. we have multiple sources mentioned - by the oil cooler and by the water pump. and these are presumed sources of the leak - i don't know that i'd consider them verified if you're not busy diagnosing what should be a really simple task - the leak - instead of playing with the heater and A/C. typically the heater function should have no impact on coolant leaking at the front of the engine....but in a sense it doesn't matter - you have confirmed seeing external coolant:

1. Positively VERIFY THE SOURCE OF THE LEAK, if it's a leak.

clean it all up if you have to. check the top of the engine and make sure the leak isn't starting there and working it's way down.
post pictures if you have to. don't get so close that we cant see context. or too far that it's hard to see.

 

[1 Lucky Texan]

also, until this is solved, do not trust the level in the overflow , check coolant level in the radiator, don't let the overflow get dry.

 

[eagleeye]

got a new OEM rad cap there?

and a OEM thermostat?

after you swap those I would consider the water pump.

miles on this?