riding out winter with a leaky heater core

[tim eh?]

just something i've noticed... i'm hoping to deal with this problem properly later and in above zero temeratures.

i have a coolant leak around the heater core. it leaks below -10'c and ends up on the inside of the d/s w/s.

i've noticed a couple of things that are helping. it seems that my leak occurs on shutdown as the coolant and pipes cool down.

i normally have what i think is a good habit... i turn everything off before i shut down the car. recently tho i started leaving the fan on a low setting (1)and i'm not entirely sure but i think the core is leaking less. maybe there is a valve that stays open and there is less pressure on the core or the pipes leading to it? also, if you open the floor vent and close the defrost (on shutdown and on startup the first couple minutes) then the coolant lands on your boots, not on the windshield.

i dunno - pretty basic ideas but it took me long enough to figure it out - certainly doesn't fix the cause but it definitely helps with the symptoms, in my case at least.

that is all, happy new year everyone.

[Ross]

Loosening the cap on the resevoir will keep the system from becoming pressurized. You may get away with leaving it loose all the time in these temps. Otherwise loosening it at shutdown will prevent it from pressurizing with the heat soak experienced when the coolant stops flowing.

[tim eh?]

Loosening the cap on the resevoir will keep the system from becoming pressurized. You may get away with leaving it loose all the time in these temps. Otherwise loosening it at shutdown will prevent it from pressurizing with the heat soak experienced when the coolant stops flowing.

i like this.... maybe instead of leaving it ****loose, i actually have a spare cap - maybe i could drill a pin-hole in it and it would allow the system to depressurize without opening the hood every time i drive? wouldn't i get air bubbles?

[Ross]

No, no air bubbles. If you use the spare cap make the hole more than a pinhole.

[tim eh?]

so i have one cap rated at 140 (psi?) and another at 200... which one should i keep intact for the summer?

and as far as 'getting away with it' - what are the consequences if i don't? i guess i will just barf coolant? ie keep an eye on it?

[bad_manners_god]

so i have one cap rated at 140 (psi?) and another at 200... which one should i keep intact for the summer?

and as far as 'getting away with it' - what are the consequences if i don't? i guess i will just barf coolant? ie keep an eye on it?

Cooling system pressure on most cars ranges from 13-18psi....sometimes more or less. I think your caps are in kpa. Keep the 200 cap for summer either way since it's above 0.

[Ross]

No consequences. The cooling system is pressurized to raise the boiling point. It's unlikely you will exceed the coolant's boiling point at atmospheric pressure this time of year.
The cap is the high point of the resevoir so air is present there all the time anyway. Just vent the cap to prevent pressurizing the system and your leak will be significantly reduced.

[russiankid]

When it was around -8C here, I didn't use the heater because I wasn't cold, my lower radiator hose was hot. So if you don't use your heater core you may be building more pressure than you think.