disco 2 heating (or lack of) Td5

Car starts and runs fine , takes about 10 -15 minutes for heat to start coming through , at first nice and cosy. After about 30 minutes , heat gradually goes and will not come back until engine is stopped and cool , then re started. Stat was changed approx. 1 month ago , no change , bled as much air out as poss using Haynes manual method. Any ideas??????
Jimbo

Is it with digital aircon control unit or with manual heater control

+1 ^^^^^^^^^
Took me by surprise the first time it happened to me. The inside of the cab had reached the temperature set on the digital aircon and started blowing cool air. I turned the temperature settings up to 25 degrees and the system worked again.

That's why i asked....if you want constant warm flow in the D2 with aircon set the temp to "HI" both sides and adjust manually the air distribution and the blower speed

Either that or set the digital aircon controller to "ECON" in which case it works just like an ordinary car heater.

brian47 said:

Either that or set the digital aircon controller to "ECON" in which case it works just like an ordinary car heater.

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ECON is only for the compressor control it has nothing to do with heating when it's cold outside, the system will behave the same on heating with ECON like without it as no need for compressor then, it will blow warm at the beginning then when it reaches the set temp let's say 21*C it will start mixing the warm air with ambient air as to keep the preset temp as constant as possible

ECON does actually make a difference to fuel consumption in my experience. I used to leave the CC on Auto all the time, but realised there is very little point when you are looking to reach a cabin temperature higher than external ambient (363 days of the year) So unless we are having one of the two hot days in the UK I leave in ECON, and occasionally switch to full Auto to pump the fluid around the compressor and ancillary AC equipment. I accept the change to the consumption is marginal on a vehicle like ours, but it all helps.

GJ1 said:

ECON does actually make a difference to fuel consumption in my experience. I used to leave the CC on Auto all the time, but realised there is very little point when you are looking to reach a cabin temperature higher than external ambient (363 days of the year) So unless we are having one of the two hot days in the UK I leave in ECON, and occasionally switch to full Auto to pump the fluid around the compressor and ancillary AC equipment. I accept the change to the consumption is marginal on a vehicle like ours, but it all helps.

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My apologies i dont want to be rude but i must say that you should learn how this system works cos all you said is a nonsense especially that in this thread we speak about heating not about cooling
1. ECON is there only to disable the compressor nothing else and the economy is made ONLY when the ambient temperature is higher than the set temperature which means compressor involvment is needed so as the compressor is disabled the consumption will be lower
2. Setting on "full AUTO" as you said has nothing to do with "pump the fluid around the compressor and ancillary AC equipment." which i can't even figure out what you mean so little sense it makes especially that the aircon setting will not affect any "pumping" of any fluid

Don’t want to get in an argument, but think maybe you are being a little harsh?

I was picking up on the reference to Econ in the thread I appreciate the issue is about heating, but Econ was mentioned and in the spirt of the Forum thought i’d share a view.

1) I am fully aware of the Econ switching off the compressor (hence less load on the engine ancillaries, therefore slightly better fuel economy. Maybe a link between the word ECON and (fuel) Economy?, but then what do I know? Very little apparently)

2) Please take a moment to re-read my post... I made the point there is no need to cool the ambient incoming air when you are looking to have a cabin temperature higher than ambient. (No need to cool air to then blend with hot from the heather matrix to make it hot again)

3) the fluid I refer to, should perhaps have correctly been called the refrigerant... which undergoes a change in state as part of the evaporative process in the refrigeration cycle. Unless I am mistaken, this usually acts as or contains lubricants needed for the longevity of the sealed system, hence by switching off ECON (or in my perhaps poorly worded post going to “full Auto”) I switch on the compressor and flow the gas/vapour/liquid around the system, providing circulation.

I’m always happy to learn, so if I really have got any of this wrong, please let me know.

Sorry but we are off topic anyway cos the OP has a problem with the heating and ECON has nothing to do with heating.... as about the refrigerant it's not fluid it's gas, the small amount of oil for lubrication lays at the bottom of the tubing and it's moved through the system by the rerifgerant's velocity when the compressor starts pumping the gas that's why i was so stumped about the "pump the fluid around the compressor .... " thing.

With apologies to the OP @jimbo917 for taking this off-topic. I had a similar issue with my heating, and it was caused by a lack of coolant in the heater matrix. I've still not got to the bottom of the issue on mine, but if you hear gurgling or running water when you accelerate hard this could be part of the problem. On a long run, mine seems to capture air in the heater matrix and therefore reduces the volume of the coolant in the matrix for transfer to heating. The feed and return pipes are below the top of the matrix, so it doesn't always seem to purge any trapped air. A strong rev of the engine seems to boost the flow and hey presto, heat again. I'll post once I've found out what the issue is on mine (maybe HG failure as the whole system seems to come under excessive pressure) as I have somebody looking at it tomorrow morning for me.

@sierrafery, couple of things if I may;

I have already acknowledged I made a related post rather than addressing the OP's question, however as the subject of ECON was raised, I though I'd share. Little did I know the mistake that was to be.

Secondly, I needed to respond to correct your assertion that I know nothing about what I am talking about. I've always respected the detailed and comprehensive understanding you have on our vehicles, and the lengths you go to to assist (including me recently concerning the temperature sensor installation). On this occasion however I did feel that you were a little strong in your response to my post. Looking back, and at your subsequent responses, I don't think I was incorrect in any respect.

Thirdly, a fluid is not, by definition, a liquid. Fluid is a term for any substance that flows, and is not solid, a substance that has no fixed shape and yields easily to external pressure (gas, liquid etc) so in accepted definition, a refrigerant is a fluid.

IMO the OP has got the answer in the first 5 replies (provided he has digital aircon control) and it's no problem just that's how the system works, so if you want we can have a friendly polemic even though my own impression is that you dont really understand how the system works and without trying to offend you i can't put that other way, sorry ...especially when you say that your problems with lack of coolant in the matrix was similar with what the OP described:

jimbo917 said:

....at first nice and cosy. After about 30 minutes , heat gradually goes and will not come back until engine is stopped and cool , then re started.....

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... which if the set temp is around 21 and the cabin temp reached this level it is perfectly normal behaviour

as about this

GJ1 said:

Thirdly, a fluid is not, by definition, a liquid.

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i agree that it's so from lexical point of view but the general conception about refrigerant is that it's gas not "fluid" as fluid can be water too while the first impression of most of people about "fluid" is not thatbit's about a gas i'm sure.... but if we go lexical then your statement that the compressor pumps the fluid is still generally wrong cos a compressor is made to pump only air/gas not fluids in general

again i apologise cos i might be rude from time to time but i admit that i have a bad temper and there are moment when the fact that english is my third language doesnt help as well

Seems like conversations I used to have with my ex-wife, regardless of being right, still wrong.....