Disco 2 Discovery 2 Td5 heater air block.

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Richeee

Well-Known Member
Posts
138
Location
Salisbury
Need help guys and gals.
Had to change my thermostat 3 to 4 weeks ago because of water leak between it and hose. All seemed good and with lock down and other vehicles not used much. Now With colder weather noticed that heater not seemed to be working.
So checked thermostat in right way round and connected with side issue to pump. All correct.
Bleed as per manual with expansion bottle raised and bleed screw on top hose. But no luck.
So now removed hose from engine to heater. The one at the side of the head by turbo and the pipe to the fuel cooler at the bulkhead. Made sure full of water and reconnected and rebled.
With the front of the car raised on ramps. Another drive. Still no good.
From cold afret 5 mins temp guage on 1/3 rd. Then over a spate of 30 seconds or so themostat must open and it rises to 1/2 way and sticks there. On the second squiggly line making the temperature sign.

Hawkeye live data shows coolant temp 83.4 and fuel temp of71.1.

Ran the ac fault diagnosis by holding the buttons as turned on key but no faults identified.

So. Am i missing something. Whats the trick to bleeding heater matrix or ideas to another solution / cause.

Had the truch since the summer and to be honest cant really say if it had previously worked.

I tried flushing out the matric and was surprised by the slow flow of water. But there again given the smaller tubes and ways there will be a resistance to free flowing water i suppose.
 
Need help guys and gals.
Had to change my thermostat 3 to 4 weeks ago because of water leak between it and hose. All seemed good and with lock down and other vehicles not used much. Now With colder weather noticed that heater not seemed to be working.
So checked thermostat in right way round and connected with side issue to pump. All correct.
Bleed as per manual with expansion bottle raised and bleed screw on top hose. But no luck.
So now removed hose from engine to heater. The one at the side of the head by turbo and the pipe to the fuel cooler at the bulkhead. Made sure full of water and reconnected and rebled.
With the front of the car raised on ramps. Another drive. Still no good.
From cold afret 5 mins temp guage on 1/3 rd. Then over a spate of 30 seconds or so themostat must open and it rises to 1/2 way and sticks there. On the second squiggly line making the temperature sign.

Hawkeye live data shows coolant temp 83.4 and fuel temp of71.1.

Ran the ac fault diagnosis by holding the buttons as turned on key but no faults identified.

So. Am i missing something. Whats the trick to bleeding heater matrix or ideas to another solution / cause.

Had the truch since the summer and to be honest cant really say if it had previously worked.

I tried flushing out the matric and was surprised by the slow flow of water. But there again given the smaller tubes and ways there will be a resistance to free flowing water i suppose.
Recently @sierrafery put up a thing where he said that you have to slightly unscrew the bleed screw then rev the engine at above 2000 revs to open summat in the system which lets a valve open, a bypass valve or summat? can't remember the details. but this isn't to be found directly in the manuals or RAVE. SF worked it out for himself and it ought to be something we all know ,
I'll see if I can find it again, but if not I expect SF will jump on a reiterate it.
Put it this way, it cannot do any harm to try it!
 
Just searched, sorry, cannot find it.:(
But that was the essence of it, slightly open the bleed screw, rev it over 2000 revs for a bit until all the air is out then retighten.
Hope you fix it.
 
Another thing, make sure that the tank's cap is tightened to max, let's hope it's valve is not stuck cos then it mixes up the whole thing
When you say hope its valve not stuck are you referring to by pass valve in the thermostat or cap.?
Sorry but may have got myself confused.
 
Thanks guys. Very nearly there.

Front raised on ramps. Stick from the seat to pedal to hold on 2000 revs, bleed screw cracked a bit and as a trickle of water came out from the hose , topped up the expansion tank. Did this for approx 10 mins until warm and the heater was deffinetly improved. Not perfect as yet but went for an essential maintenance journey and with heater on high was comfortably warm.
Will let it cool down and then repeat. Wondering if when topping up i should had raised the expansion bottle higher. Will tomorrow when have another go. But loads better.
Thanks again.
 
Front raised on ramps.
You better not raise the vehicle's front for that cos it has rather bad effect on the flow and the radiator's top gets above the bleed hole so air can be trapped there, you only have to raise the tank with horizontal vehicle
Wondering if when topping up i should had raised the expansion bottle higher
No, that's only to fill the empty system
 
Getting there guys but still not perfect. I would say its warm rather than hot.
Have tried the 2000 rev bleeding trick with the bleed valve cracked open several times. Have also replaced the pressure cap.
The pump is working fine because with the bleed valve removed water will bounce off the opened bonnet and get myself wet.
I will run as is for a while through a few cooling and heating cycles.
And see if the air block clears.

Also beginning to wonder of a good wash out and descaler might do some good.
But will run as is for a while.
 
Yes, a cooling system flush would be a good move cos the heater matrix might be gunked up and there is not enough flow through it, i recommend this one https://www.ebay.co.uk/itm/Liqui-Moly-Radiator-Cleaner-1804-300ML-/383263360570 which worked well for me on all my cars... extract 300 ml of coolant from the tank, put this in and drive it so that day without fear then at the end of the day flush with water and fill with 50% OAT mix, bleed it well, job done
 
Heater now works. Thanks all.
A dose of Liqui Moly as suggested by Serrafery, A fun couple fun of hours driving round the New Forest in attrocious conditions on my favourite back roads, let it cooled, drained, flushed, refilled and road tested, and heat. In fact had to turn it down to reduce the temp.
Sorted.
Now to look at the heated rear window which is popping fuses. Have read several threads on here about connectors and route ro rear door so will have fun tracking that down.
 
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