Coolant Flow through Heater Core

[llll1l1ll]

I am only curious:

Does the coolant flow consistently through the heater core or is it only when I turn on the heat?

I ask this since I have a small coolant leak somewhere and I was wondering if it was a cracked hose leading to/from the heater core.

[5KWattson]

im pretty sure it does, when you turn off the heat i believe it only shuts the blend door

[llll1l1ll]

Thanks! That's what I thought. I guess I shall have to take a look sometime in the evening this week or next weekend.

[5KWattson]

me too, i get a whiff of coolant once in awhile if i havent ran my heater for about a week than flip it to hot ill get a quick smell of sweetness

[Toms73NovaSS]

There is an electronic valve in the piping leading into the heater core. When the temp setting is set for ac/cold it shuts off the valve and stops the flow of coolant through the heater core. This way the ac does not have to compete with the heat of the heater core.

[llll1l1ll]

But does the coolant still flow through the hoses into the firewall - just not through the heater core itself?

[jlevie]

The heater valve blocks the flow through both the hoses and the core with heat off. But that doesn't mean that a leaking heater core can't leak with the heat off since the valve only blocks the flow through one hose.

[llll1l1ll]

That's what I think is happening. I am certainly going to take it apart one evening or this weekend. It's such a slow leak that it's not dire.

I also never smell coolant in the car on a normal basis; however, when I used the heat I did smell a whiff of coolant.

I also suspect this area as I cannot find any other evidence of leaking coolant in the engine area.

[E30_80Y]

I had a blow out today, i heard an explosion and then hot water on my right ankle. water was leaking out of the lower center console area and i had white smoke quickly fill the cabin. I took apart my dash and check the heater core and the white plastic with hose going into it was kinda pushed open and the foam seal messed up. Anyone know what happened?? i have a m42 e30 with a s52 swap.

[jlevie]

I had a blow out today, i heard an explosion and then hot water on my right ankle. water was leaking out of the lower center console area and i had white smoke quickly fill the cabin. I took apart my dash and check the heater core and the white plastic with hose going into it was kinda pushed open and the foam seal messed up. Anyone know what happened?? i have a m42 e30 with a s52 swap.

Your heater core failed. That may be just because the plastic was old and brittle. But it could also be that you have excessive cooling system pressure from a leaking head gasket.