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Heat Core Issues, or "How Tyler can't keep coolant in his car"

Posted by Earendil 
First of all, God Bless BMW engineering. More on that in a second.

I made it all the way to Spokane, 300 miles, without losing much coolant, if any at all. I then proceeded to drive 40+ miles around the city, doing typical city driving. No problems at all. I attempt to go home though, and 20 miles outside the city, my car is engulfed in a cloud of white smoke that, if I didn't know better, would make me think I was about to have my car invaded by a SWAT team.

So I rapidly pull over, run to my trunk to grab a screw driver, and then pop the hood. Yeah, I have my priorities straight smiling smiley
I open the hood and let out a large plume of steam, only to find a perfectly dry engine bay. So I take a look under my car to see what can be seen, and what I find is a facet flow amount of coolant coming down from around the back of te transmission. @#$%.

So After a bit more looking, I determined that something in a firewall has come loose, and is dumping coolant. Thanks to BMW, it is extremely easy to bypass the heater core right there at the firewall. Perhaps all cars are this way, but it wasn't something I thought would be easy without addition connectors/hoses, and yet it was. I did this and added water, nothing more came out of the bottom of the car, and I made it the remaining 280 miles home without a hitch.

Hopefully I didn't do any damage doing what I did. Also, heat is a good thing. It was 50 degrees outside, and suffice to say that after 5 hours of driving, it was pretty close to that temperature inside the car. Now to do some research into how to get at the heater core. I'm hoping that whatever hose connects to the core is what came off. While I'm doing research, and waiting for time/money to fix this new problem, should I know anything about the current state of my car? Might the coolant be on something that should be washed off? No coolant made it into the cabin, so no problems there. But the space between the firewall and the dash is a mystery to me smiling smiley

1989 - E30 - M20 - Manual. Approximately 270,000 miles
2000 - E46 - M52TUB28 - Manual. Approximately 110,000 miles

Somebody did a write up on that, maybe on the old site? It didn't look that bad, just a series of steps. There was something about a 5 speed vs. a automatic I think.

if your car has A/C then the core is a simple job. If no A/C then it's a lot more complicated and a pain in the neck.

Which do you have?
That was it, I couldn't remember which fundamental option it was.

Don't tell me about non A/C heater core replacements! I enriched my cursing vocabulary on that one.
My car has A/C. But it's supposed to rain through Saturday, so I won't be getting to it for a while. Thanks for pointing out that difference, I'd have hated to start taking it apart as if I didn't have A/C!

1989 - E30 - M20 - Manual. Approximately 270,000 miles
2000 - E46 - M52TUB28 - Manual. Approximately 110,000 miles

My car has A/C.
You are so lucky. In that case the job is dead simple.

It definitely sounds like your heater core burst. You would have known right away if it had been the heater valve leaking, because then all the coolant would have landed on your feet. Instead the heater core drained out safely via the route that the A/C normally drips water.

Here's a link showing what's involved in replacing the heater core, including my contribution of how much of a beotch it is if you don't A/C...
My car has A/C.

god bless america(n spec bmws)

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Have changed my heater recently due to small leaks fogging my window more than the heat could evaporate. From BMW it is very pricey. Might want to try another source. There are two types depending upon model year. One has plastic tubes and the other, metal. The valve is removable from the radiator part and requires new seals to replace.

The BMW flat rate book says 1.2 hours to R&R. Took me about 4 times that long.

Bob in Everett
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