Disco 2 TD5 - Heater Blowing Cold

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Pauldw

Member
Posts
75
Location
North Worcestershire
Having replaced the cylinder head on the vehicle and running it up (bleeding the cooling system and performing the “heater hot” test) – the old top hose began leaking (due to age / de-lamination). I dispatched my wife to collect a new replacement accordingly.

I fitted the replacement pipe, bled the system and believed all to be good - didn't recheck the heater at that time...weather was good at the time and it had heated up perfectly, hadn't it......

Sometime later, I noticed the heater wasn’t blowing any hot air at all – I presumed it was an airlock – so re-bled the system again – no change, so I replaced the thermostat with a new part – again no change. Temperature gauge has always stayed perfectly in the middle, even when towing.

Last weekend (with the onset of markedly colder weather), with some time on my hands to investigate further, I flushed out the whole cooling system (in case of any sludge – but was all clean). On flushing from the heater hose towards the radiator top hose the water wouldn’t flow at all. Thinking there may be a blockage I traced back to the T-piece in the top hose. I couldn’t blow through the pipe – so cut off the factory crimped hose clip to find that the bore in the T piece had not been drilled through to allow flow…!

I drilled out the T piece accordingly, refilled and bled – lo and behold the heater began blowing lovely and hot!

The moral of the story - always check and test new parts if you can before fitting....and check everything again...
 

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Having replaced the cylinder head on the vehicle and running it up (bleeding the cooling system and performing the “heater hot” test) – the old top hose began leaking (due to age / de-lamination). I dispatched my wife to collect a new replacement accordingly.

I fitted the replacement pipe, bled the system and believed all to be good - didn't recheck the heater at that time...weather was good at the time and it had heated up perfectly, hadn't it......

Sometime later, I noticed the heater wasn’t blowing any hot air at all – I presumed it was an airlock – so re-bled the system again – no change, so I replaced the thermostat with a new part – again no change. Temperature gauge has always stayed perfectly in the middle, even when towing.

Last weekend (with the onset of markedly colder weather), with some time on my hands to investigate further, I flushed out the whole cooling system (in case of any sludge – but was all clean). On flushing from the heater hose towards the radiator top hose the water wouldn’t flow at all. Thinking there may be a blockage I traced back to the T-piece in the top hose. I couldn’t blow through the pipe – so cut off the factory crimped hose clip to find that the bore in the T piece had not been drilled through to allow flow…!

I drilled out the T piece accordingly, refilled and bled – lo and behold the heater began blowing lovely and hot!

The moral of the story - always check and test new parts if you can before fitting....and check everything again...
Agreed! The return from the heater matrix flows through the fuel cooler so your fuel would have been a bit hot!
 
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