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Need help diagnosing heater issue (E46)

Discussion in 'E46 (1999-2006)' started by cmking, Dec 25, 2011.

    cmking guest

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    Hey all, it's finally cold enough for the heater, and lo and behold, she doesn't heat so well.

    I replaced my thermostat around Thanksgiving and lost a fair amount of coolant, and I fear I didn't properly bleed the system, and now I'm stuck. The floater in my expansion tank also broke, so my cooling system is just in a heap of trouble.

    Car doesn't overheat, almost perfect 12:00 on the temp gauge. Fans blow fine, so not the FSR.

    If it isn't the coolant bubble, my other suspects are the heater solenoid not fully opening, and the interior temperature sensor not properly reporting the interior temp. Exterior temp sensor works fine.

    Other issues: long running P0171 and P0174 issues, still chasing them down.
    Attached is my INPA reading while the car is running:
    [IMG]

    cmking guest

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    Update: it isn't my heater solenoid. Pulled it out and tested, works as it should.
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    MGarrison

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    Does your car have a supplemental/aux. coolant pump?

    cmking guest

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    Not that I know of. Went to austrotech today, Gunther tried bleeding it and only got the temp up to lukewarm. He still suspects that it's the heater valve.
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    MGarrison

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    I plugged in a production month of June; if this diagram is accurate, and if what you're calling the heater valve is what realoem.com labels as the water valve, it looks like that's the only thing between the connecting hose from the block or water pump and the heater core. If the two hoses running to the water valve are easily accessible, pull 'em off the heater valve, and splice 'em together with a barbed hose connector of the correct diameter. If you get the engine up to full temp and get full heat with the blower motor on full, then it would appear your culprit would likely be the water valve. If there's nothing else piped into the circuit and you're still not getting heat, then perhaps it would suggest there's a blockage somewhere, or the blower ain't blowin', or hot coolant isn't going through or getting to the heater core. Since the rest of the engine temps seem ok, and you aren't losing coolant, or getting coolant smells or other evidence of coolant leakage, that would probably imply the water pump is working ok.

    http://www.realoem.com/bmw/showparts.do?model=AN37&mospid=47720&btnr=64_0890&hg=64&fg=18

    cmking guest

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    We pulled the hoses off yesterday, and while we didn't have the fittings to connect them in the garage, we did pressurize one side of the valve, and open and close it to check how well it worked. I'll run to the store and pick up the fittings today....think they're 3/4"??

    Thanks
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    MGarrison

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    I don't know where you might find the electrical specs for testing the valve, but if you can dig up the electrical diagram for the circuit that actuates the valve, there might be possibilities there as well - something like a bad relay, perhaps. If the valve is perfect mechanically, you'll want to make sure it's getting the signal/voltage/whatever to be opening. I wonder if setting your temp to max is supposed to be an override that bypasses whatever else might electrically limit the circuit (I, obviously, am not an electrical engineer ;-)). However, there is the design of the valve itself - perhaps possible there's some electric/electronic component within the valve that keeps it from opening that standard testing doesn't so easily reveal - unfortunately it's an $82 part, so would be a drag to buy one to swap in without being sure that's the culprit.

    http://www.autohausaz.com/search/product.aspx?sid=tuar0hymkp10bb553pnjfzyr&pn=W0133-1609779,

    See if you can't track something down here:

    http://wedophones.com/BMWManualsLead.htm

    Sorry, no idea what your hose diameter is!

    cmking guest

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    No luck on anything yet, and it appears everybody is still hungover from new years and doesn't want to ship my parts. About to have to cave and call the stealership....it sure did get cold fast!

    cmking guest

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    BREAK THROUGGHHH!!!!

    Bypassed the heater valve, and had heat (but it was very engine speed specific....above 4k rpm it hits 95+ degrees from the vents, but at idle, it drops down to 65-70 degrees)

    Put in the new heater valve, and same thing. Had heat at high rpms, but below 1k, temp drops pretty significantly.

    Any ideas??
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    MGarrison

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    steven s

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    Sometimes it takes a few times bleeding the air.
    There is also http://tis.spaghetticoder.org/e46/.
    You might want to talk to Mike Foerster in Parts @ Century. He's a long time club guy.

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