W460 limited coolant supply to the heater matrix

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Sat, 25/11/2023 - 09:19
Talljohn
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Location: Buckingham

Is there an auxilliary coolant pump on the 230 engines? My heater matric isn't receiving hot water. I removed the pipe from the heater valve and beyond the initial burst of water pressure, I was left with only a trickle being supplied to the valve. Can't quite understand why this would be the case. Water pump isn't noisy, so assume it's pumping OK. Thermostat is closed, and generally seems to remain so, might need a new one there.

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Tue, 28/11/2023 - 15:27
#1
Nick123
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Location: Argyll, Scotland
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Re: W460 limited coolant supply to the heater matrix
FWIW... It might be worth investigating a possible airlock and back flushing the system with a hose. I have also experienced a heater valve (under the bonnet, in front of the plenum chamber) not being open even when it looked as if it should habe been.
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Wed, 29/11/2023 - 09:59
#2
Jdring
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Location: South of Oxford, UK. 87' 230GE SWB Manual, 89' 230GE SWB Auto, 2012 G350Bluetec LWB
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Re: W460 limited coolant supply to the heater matrix
It does sound like the thermostat. Definitely change that if it is shut! Flow should be like a tap when it opens. Just be careful not to snap one of the 2 thin bolts holding the thermostat housing otherwise the 5 min cheap job becomes a pita. That would explain the trickle. G heaters are known to be good when they are working, along with the fan, which I think you did.
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Wed, 29/11/2023 - 19:36
#3
Talljohn
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Re: W460 limited coolant supply to the heater matrix

Found the problem! The steel return pipe was corroded and completely blocked. New stat in place anyway, but now I have heat, just in time!

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Wed, 29/11/2023 - 22:55
#4
Nick123
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Re: W460 limited coolant supply to the heater matrix
All's well that ends well.
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