Can there be heat without a heater core?
Thread Starter
Super Member
Joined: Nov 2018
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From: Atlanta, GA
2001 S500 (W220) / 2007 GL450 (X164)
Can there be heat without a heater core?
My heater core is bad
auxiliary pump bad
heater control valve bad
i was told if I change my aux pump and heater control vale I would get some heat just not full strength…
is this true?
auxiliary pump bad
heater control valve bad
i was told if I change my aux pump and heater control vale I would get some heat just not full strength…
is this true?
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NGL450 w/EORP, S550
No. I would not do that.
Cause you’re just putting hot coolant through a bad/leaking heater core and creating more problems like foggy windows, breathing in glycol fumes, inducing a water leak in your Dash etc. etc.
Cause you’re just putting hot coolant through a bad/leaking heater core and creating more problems like foggy windows, breathing in glycol fumes, inducing a water leak in your Dash etc. etc.
Last edited by Max Blast; Jan 12, 2025 at 01:03 PM.
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From: Allentown, PA
'08 GL 320 CDI
The core is what allows heat to be made by the fan blowing over it. What was the reasoning behind behind whoever told you that?
Besides, if you have a bad core - you either need to bypass it (eliminating heat) or replace it. I can't think of any other options.
Besides, if you have a bad core - you either need to bypass it (eliminating heat) or replace it. I can't think of any other options.
Thread Starter
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Joined: Nov 2018
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From: Atlanta, GA
2001 S500 (W220) / 2007 GL450 (X164)
what has been verified is that I need a new aux pump and heater control valve
Thread Starter
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From: Atlanta, GA
2001 S500 (W220) / 2007 GL450 (X164)
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Thread Starter
Super Member
Joined: Nov 2018
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From: Atlanta, GA
2001 S500 (W220) / 2007 GL450 (X164)
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From: Allentown, PA
'08 GL 320 CDI
A heater core can get plugged... or leak. If it leaks, you will lose coolant and the leaking coolant will end up below your seats.
What kind of smoke? If coolant fell on something hot (can't imagine anything behind the dash being THAT hot, though) and it started smoking it would be obvious as it has a very distinct smell.
Thread Starter
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Joined: Nov 2018
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From: Atlanta, GA
2001 S500 (W220) / 2007 GL450 (X164)
So your heater core is NOT bad as you said in your first post?
A heater core can get plugged... or leak. If it leaks, you will lose coolant and the leaking coolant will end up below your seats.
What kind of smoke? If coolant fell on something hot (can't imagine anything behind the dash being THAT hot, though) and it started smoking it would be obvious as it has a very distinct smell.
A heater core can get plugged... or leak. If it leaks, you will lose coolant and the leaking coolant will end up below your seats.
What kind of smoke? If coolant fell on something hot (can't imagine anything behind the dash being THAT hot, though) and it started smoking it would be obvious as it has a very distinct smell.
2. I was driving and noticed there was no heat then the next day it came back again and then the day after that it was gone. I drove about 3 miles to Chick-Fil-A and while parked I just started seeing smoke come from the dash like something was burning. I don't remember a distinct smell. There could have been one but I just don't remember.
I took the car to 2 different shops and they both found issue with the Aux Pump but said while the heating core could be an issue they aren't comfortable making that determination without changing the Aux Pump.
The THIRD shop I took it too said there is an issue with the Heater Control Valve. He has since changed both (aux pump and heater control value) and while he originally stated that the heat would be at 70% strength...he is now saying it is maybe at 30% strength.
Without STAR how can you tell if the heater core is bad?
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From: Allentown, PA
'08 GL 320 CDI
"Below your seats" means under the floor boards where there's a whole bunch of electronics.
I can't comment on the % thing that you're referencing as it's not clear how that diagnosis is being attained.
Are things better now that the aux pump and control valve are replaced?
STAR can't diagnose a bad/plugged core. Plugged can be checked the old fashion way of flushing. Bad/leaking is as I mentioned above and about my second sentence above.
I can't comment on the % thing that you're referencing as it's not clear how that diagnosis is being attained.
Are things better now that the aux pump and control valve are replaced?
STAR can't diagnose a bad/plugged core. Plugged can be checked the old fashion way of flushing. Bad/leaking is as I mentioned above and about my second sentence above.
Last edited by DennisG01; Jan 16, 2025 at 08:50 AM.
