I suspect I have a heater core leak as I can smell coolant when I first turn on the heat in my car. So I decided to pull the center console and do some checking, and what I found was nothing. No signs of any leaks, no wet/damp carpet, and clean, open drain lines. Then I borrowed a cooling system pressure tester, set it to 16psi (which, IIRC, is about where the stock cap starts to blow) and left it overnight to sit. The next morning it was still on 16psi (+/- about 0.5) and again, no signs of any leaks. So... Do I bother replacing the valve, core, lines, etc just because I smell coolant, or do I trust the tests? Will the heater core valve be open (i.e. allow pressure in to the core) if the car is off but the heat dial is set to hot? Are there any other ways to confirm/deny a heater core leak that I could try?
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Does the heater core valve only controls the flow into the heater core? If i remember right this is how it works. Considering how you pressurized the cooling system, it would build up pressure on the return line and then inside the heater core. If I'm right about the valve, it would've dropped pressure overnight if the core was leaking. -
hmmm, good point. I didn't think about the backflow part. So I guess I'm still getting mixed signals between my nose and the pressure test :/Comment
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Does it fog up when you first turn the fan on in the morning?
I'm guessing you looked at/felt all the lines and the valve, too.
I'm a procrastinator- if you're not losing pressure or coolant,
you don't have a problem!
tnow, sometimes I just mess with people. It's more entertaining that way. george gravesComment
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No fog, just the smell. And ya I've inspected all the lines, no signs of anything. The pressure dropped another 1/2psi during the day, but no drips from anywhere. It's lost 1psi over 20 hours, which means no 'real' leaks. There could be a hariline crack somewhere, or it could be pressure escaping back through the tester.
Also I turned the car to position 2 and cranked the heat (in order to activate the valve) and there was no pressure change. So yes the system pressure and heater core pressure are always equalized.Comment
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Yep, then maybe a seeping seal on the end tank on the heater, or yeah, a small crack.
They weren't very expensive last I looked- maybe just replace it?
tnow, sometimes I just mess with people. It's more entertaining that way. george gravesComment
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If you smell coolant when the heater is turned on, the core or the valve is leaking. The leak may be a very small one that won't show up on a pressure test and it only takes a drop or two of coolant to be noticeable. If you are waiting until the engine is hot to turn on the heater I'd suspect the core over the valve.The car makes it possible, but the driver makes it happen.
Jim Levie, Huntsville, ALComment
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Dude, your cooling system is in amazing shape - it's normal for most cars to lose 2-3 psi overnight, let alone 24 hours. You sure its a coolant smell? Might be something else. I guess it'd be hard to say without actually looking into the box surrounding the core, but based off of your pressure loss I'd say you don't have any leaks to write home about for a while.Comment
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Found it! There is a very small leak in the core where the plastic end tank meets the aluminum core. It's so small I had to reach behind the carpet and feel for it, but it's there.
What's the story on the valve? Should they be replaced at the same time as the core? Mine isn't leaking and seems to work fine.Comment
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Aren't those valves expensive as fuck? I hope for the sake of your wallet that it's fine.
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Looks like it's about $180. At least they're easy to get to/replace...Comment
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I had a leak on my car. Windows would fog up. It was the heater core valve or tubing.....it was so long ago I forget. Anyways, point is, that it was a recall item, and I got the part for free. So you might look into that.Originally posted by CorvallisBMW View Post
(I think the dealer was going to do the labor for free too - but I was going on a road trip the next day - So I did it myself - I just remember fishing the tubes through the firewall was a PITA for some reason)Originally posted by Matt-BComment
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I was just going to mention that recallOriginally posted by george graves View Post
--sent from my igloo via carrier penguin(OO=[][]=OO) For LifeComment
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Hmmmm I'll get in touch with my service advisor buddy. I verified it's the original core, so if there's a chance of getting it replaced under recall I'll take it!Comment
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Checked with BMW, the car has no open service tickets so no-go on the recall. I ordered a new unit from Blunt, came in the very next day. He sure knows how to please a man
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if not i have one FSComment
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