Cheers,

dellboy1959 said:

2open the heater valve to full

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To make sure I don't do something silly again, this simply means turning the salon heater on, right?

discool said:

air blending heater system

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Air blending what?

1spin said:

Is it a 300 tdi ? or 200 , it dont say in the post...

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It doth in the signature it's a 300tdi

dellboy1959 said:

That still doesn't explain why the matrix is permanently hot and how the fan can possibly know there is air free coolant running through it?.

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Yes does... you were told NO valves and wtf has a fan got to do with it.

The air-blending system has a matrix that is heated constantly.
The temperature control opens and closes flaps that blend heated air with cold air from outside.

So why say leave the controls on HOT

jamesmartin said:

air gets warm ,or you can feel both pipes were they go through bulkhead both should be hot if engine is

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Nope,you still got me on that one.maybe discool could elaborate seeing as how he was the first one to jump down my throat

when you fill system it can flow through any part including heater matrix (heater matrix cant have flow switched off as there is no valve or tap )as its all open ,if there isnt a good flow through heater matrix air wont get warm when you put heater on ,putting heater on tells you coolant is flowing as does feeling pipes if one going in is hot and one coming out is hot coolant flowing ,likewise if top hose gets hot you know thermostat is open

@dellboy1959, just to double-check - do I simply turn the heater on in the salon?

dellboy1959 said:

That still doesn't explain why the matrix is permanently hot and how the fan can possibly know there is air free coolant running through it?.

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dellboy1959 said:

Nope,you still got me on that one.maybe discool could elaborate seeing as how he was the first one to jump down my throat

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It was quite plain that the thread was on a 300tdi therefore as you don't know the cooling system fitted this vehicle to this vehicle then say so.

And for the info you want just Google.

motorhead said:

@dellboy1959, just to double-check - do I simply turn the heater on in the salon?

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turning heater on will let you know coolants circulated not allow it to

jamesmartin said:

there no tap or valve for heater matrix, coolant just flows through it all the time ,running fan lets you know coolant has circulated through it

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It could have something to do with this statement

OK people,
It would seem i made a big error on this post as I'm the first to admit that as far as landys go I'm old school (plugs/points and generally series3)
Like most people on here It's a learning curve (even the most experienced)
I don't profess to like the newer ecu/electronic dependent and weird alien type landys but sign of the times I suppose.
Apologies for leading people astray but this was in the best intentions and in know way done on purpose.
I may pop back on occasion if i need advice but i feel it best if i don't participate,
Regards,
Dell.

dellboy1959 said:

OK people,
It would seem i made a big error on this post as I'm the first to admit that as far as landys go I'm old school (plugs/points and generally series3)
Like most people on here It's a learning curve (even the most experienced)
I don't profess to like the newer ecu/electronic dependent and weird alien type landys but sign of the times I suppose.
Apologies for leading people astray but this was in the best intentions and in know way done on purpose.
I may pop back on occasion if i need advice but i feel it best if i don't participate,
Regards,
Dell.

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dont be hard on yourself nobody knows it all, we learn from each other different things

jamesmartin said:

turning heater on will let you know coolants circulated not allow it to

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Sorry, I'm being extra thick here. I don't get what you're trying to say

So, if I turn the heater on, take the rad plug out and get the engine to the working temperature, the airlock should hopefully disappear?

motorhead said:

Sorry, I'm being extra thick here. I don't get what you're trying to say

So, if I turn the heater on, take the rad plug out and get the engine to the working temperature, the airlock should hopefully disappear?

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Run engine to operating temperature. Put heater control to HOT. Turn on heater fan in cabin. If hot air is coming out of vents you have flow through your heater matrix.

Turning the heater to hot does nothing to the matrix, it merely allows hot air to circulate into the cabin. The matrix should be hot whenever the engine is at working temp. If the heater is turned to cold it closes an airflap which stops the hot air.

So if no hot air from heater you probably have an airlock. If so jack the front end of the car up so the rad plug is higher than the matrix before filling with coolant.

Hope that links all the things others have already said.

@alexdon, thanks

Ok, so I got it to working temperature in 3 minutes, put the car on the slope hoping that some air would come out but nothing happened.

The heater is working, I got lots of hot air in the cabin almost instantly.

The radiator is totally cold.

When I remove the rad's cap and undo the reservoir's cap, coolant will try to escape from the rad's orifice. Same happens when I open the thermostat's cap. The moment I replace the reservoir's cap, coolant stops coming out of the radiator (or thermostat depending on which one is open).

So, what is it? A blocked rad?

you need to check top hose is getting hot so you know thermostat is open and if rad is still not hot all over replace rad with a new one

the top hose is lukewarm but the U-shape thingy that connects the top hose with the thermostat housing is substantially warmer. Mind you, I didn't run it as far as yesterday but if my memory doesn't fail me, the top hose was rather hot yesterday.

rad obviously wont get hot till thermostat is open ,you need to give it a bit more time to warm up by the sound of it then check

I'm sooo afraid to cook the engine, it's such a good engine! Ok, I'll try to warm it up slowly so that I can eliminate the thermostat.

jamesmartin said:

rad obviously wont get hot till thermostat is open ,you need to give it a bit more time to warm up by the sound of it then check

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Just what i was thinking of posting.

I had to refill my system last week I waited with the engine running and still the top hose was cold then after blipping the throttal a few times wham! it's red hot.. so to speek... the thermostate had opened.

motorhead said:

I'm sooo afraid to cook the engine, it's such a good engine! Ok, I'll try to warm it up slowly so that I can eliminate the thermostat.

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How are you going to warm the engine slowly? the coolent is circulating around the engine very little is going through the rad to be cooled via the fan.
Just keep the revs up and as soon as the thermostat opens the coolent will circulate and the levels will adjust, let the engine cool and top-up the expansion bottle as required.

motorhead said:

I'm sooo afraid to cook the engine, it's such a good engine! Ok, I'll try to warm it up slowly so that I can eliminate the thermostat.

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Motorhead, here's what you need to do (I'm typing this in the order this must be done, OK?):

1. Before you do anything else, take the cap off & check the coolant level in the header tank, it should be at the height of the seam on the outside. If it's low,top it up to that seam. Now put the cap back on (v.important).

2. Now go to the thermostat housing and remove the plug and check the level. If it is low, top up until it is full, then replace the cap.

3. So now we know that the coolant is fully topped up, start the engine and let it tick over for 5-10 minutes, or until the heat can be felt in the top hose going into the radiator. This tells us that the thermostat is now open. Also check the bottom rad hose to see the temp there.

4. Now carefully remove the header tank cap and leave it off. Leave the engine ticking over for another 10-15mins. This should clear any air from the system.

5. Whilst this is going on, check the temperature in the header tank - is it cold or is there at least some heat there?

6. If there is no heat in the header tank, check for heat in the small bore hose coming from the thermostat housing, another small bore pipe that goes from the top left of the rad to a small black plastic device where the two pipes go into one. Check the pipe that goes from this plastic device to the header tank. Is there heat in all of these pipes? Please note down carefully which are not and which are not !!

The reason for going through all this testing it to: a. remove an airlock & b. establish if there are any other issues.


I recently had temp issues with my wife's TDi 300 Defender and went on a trail of replacing all and sundry rather than doing a proper diagnosis. I changed:

1. The thermostat - twice!! The first one upon testing with boiling water in the kitchen, was faulty

2. All hoses, just as preventive maintenance.

3. Water pump;

4. Radiator;

5. and finally the two into one small bore hose with the one way valve in it.


So now I have a whole new coolant system, but the actual fault was cured by replacing the hose assembly with the 1-way valve.

Do the diagnosis, BEFORE doing what I did !!!!!