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Old 01-30-2013, 07:49 AM
jamrobin jamrobin is offline
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Location: Deep River, Ontario, Canada
Join Date: Jan 2013
Posts: 26
Mein Auto: 94 318is, 99 M3 cabrio
Monday on the way to work I had no heat whatsoever in the 318... (and also on the way home!) It was -35C with the wind chill and I swear it was getting even colder inside the car!

The temperature guage was at it's normal high noon position, so I proceeded to try and find another reason for the problem... checking fuses, looking for a stuck heater valve... Once the car cooled a bit I opened the rad cap and lo and behold no coolant for as far as my flashlight could peer... Topped it up and went for a drive... at first no change but then I went up a steep hill and Ta Da! Heat! I proceeded to go back home and "burp" the system and all is well again.

My concern is where the hell did the coolant go? I thought I detected a faint coolant smell in the fall when heating season began, and topped up then but hadn't really thought about it since... I'm guessing that this points to the heater core? How nasty a job is it to swap that out?

I've contemplated putting some kind of stop leak in until spring but I'm concerned that if it can in fact stop a leak it can probably plug a water passage too?

I guess for now I'll just keep some pre-mix in the trunk and top up and burp as needed... and take the M3 whenI need to be on the road more than an hour.

I would love to hear thoughts on how tough a job the heater core is, or if anyone thinks stop leak is safe to use as a stop gap measure until April or May when I can start tearing stuff apart without frost bite (and breaking every plastic part I touch)?
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