Overheating after coolant flush

O' dear not another post. How can we have 4 pages on how to vent a Discovery cooling system?

😱never new it was that difficult!😁 onto the third page of instructions! Be quicker to RTFM!!!

dellboy1959 said:

The heater matrix is part of the cooling system so if you do a drain/refill the heater Must be in the max open position (hot) in order to allow coolant into it.
If you don't do this you end up with a massive air lock.

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sorry the heater matrix is part of the water cooling system and therfore always has water at the temp of the engine,the heater control,hot/cold only flips between blowing air through the matrix and bypassing the matrix it has nothing to do with the coolant level!!!

thebiglad said:

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

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Thank you, very good instructions. I actually managed to get some air out but it's still not looking good. After 10 minutes of driving, this is the temperature that I get:



Before the flush I needed more than 10 minutes to hit the "working temperature" mark. I'll repeat your instructions once again. Maybe there's still some air in the system

discool said:

O' dear not another post. How can we have 4 pages on how to vent a Discovery cooling system?

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Let's make it 6 pages, shall we?

to be honest 300 tdi if filled fully with bungs out, and replaced as they overflow ,take little bleeding air out its straight forward unlike some other engine systems ,feel the top hose ,feel the rad feel the other pipes,if you think its getting hot find out why

motorhead said:

Thank you, very good instructions. I actually managed to get some air out but it's still not looking good. After 10 minutes of driving, this is the temperature that I get:

Before the flush I needed more than 10 minutes to hit the "working temperature" mark. I'll repeat your instructions once again. Maybe there's still some air in the system


Let's make it 6 pages, shall we?

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Now I don't understand, what wrong with reaching the operating temp after 10 minutes???? If anything at all, it's a bit slow, but not abnormal as it depends how much work the engine is being asked to do, in those first ten mins - light demand slower warm-up.

On face value it appears to be perfect???

What you will probably find is that over the next few days, the coolant level will reduce as the air in the system (if any?) is expelled. This is normal behaviour and you just need to monitor and top-up as required.

PS. One thing you might care to check - after a run where the engine is fully warm. Stop the engine and check the stiffness of the fan to turn, it just turn quite easily. If it's too stiff it will over cool the engine. It's a subjective test I know, but do it anyway.