300tdi heating issues

old landyman · Dec 28, 2022

Last 2 wk, I've noticed heater blowing cold after warming up to normal temperature and remained cold throughout, with engine running at tickover, the red engine oil can symbol flickers on then goes out, I am concerned to do a long journey as doing further damage, there is no sign at this time the head gasket gone, exhaust smoke clear,no emulsion in the rocker cover, no coolant, oil loss, but wondering if the oil temperature sensor is in the same circuit as the pressure sensor. Any similar problems out there?Tim

discool · Dec 28, 2022

0k, cold heater possible a permanent open engine thermostat maybe, but as the Tdi is a cool running engine to start with and ambient temp is below freezing doesn’t help, so try partially restricting the air flow in to the radiator and if the heating returns.
A flicking oil pressure warning lamp due to low oil level, or even a iffy oil pressure switch which is easy to replace.
Engine oil temperature sensor isn’t part of anything… theres isn’t one fitted, but depending on your discos spec the transmission oil temperature has a sensor with in it’s cooling circuit.

old landyman · Dec 28, 2022

discool said:
0k, cold heater possible a permanent open engine thermostat maybe, but as the Tdi is a cool running engine to start with and ambient temp is below freezing doesn’t help, so try partially restricting the air flow in to the radiator and if the heating returns.
A flicking oil pressure warning lamp due to low oil level, or even a iffy oil pressure switch which is easy to replace.
Engine oil temperature sensor isn’t part of anything… theres isn’t one fitted, but depending on your discos spec the transmission oil temperature has a sensor with in it’s cooling circuit.

lynall · Dec 28, 2022

Try an oil pressure sensor first.
Is tickover speed to low?

Heater will be stat, easy enough to change, but do make sure you bleed it correctly.

miktdish · Dec 28, 2022

If I start my landy and dont rev a little, my oil light flickers on too, a quick blip of the throttle and it goes out and stays out. Same with the alternator/charge light.

The heater is fed from the top of the engine and water is pumped around before the thermostat opens and when it's closed. If the stat is open all the time water is pumped around the radiator and there is often not enough pressure to go around the heater matrix.

sierrafery · Dec 28, 2022

Touch the inlet and outet pipes of the heater core in the engine bay, if the inlet is warm and outlet cold the core is clogged and that's why you dont have heat, old cores used to be full of gunk, ask me how i know

KiwiTDI · Dec 29, 2022

Have you checked the coolant level? And if required topped it up in the correct way so as to remove any air in the heater circuit?

300tdi heating issues

old landyman

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discool

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old landyman

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lynall

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miktdish

Guns n Chainsaws

sierrafery

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KiwiTDI

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