w124 E250 Diesel Coolant Change

[lukebowman551]

I had to replace my oil to water heat exchanger after driving over a rather big rock and destroying it recently. I managed to get a replacement part from a breakers £55 instead of £200 from merc and fitted it no problem.

When i came to re-filling the coolant i seem to have a bit of a problem getting the air out of the system. I think i've sorted it but still doesn't seem like the full 9 litres has gone back in. Any tips on bleeding the air out would be much appreciated.

I've seena few threads and have tried the following:

Parked up hill so that the expansion tank is the highest point.
Turned the heater vents to hot.
Squeezed the top and bottom hoses as the engine was running.


Any other tips?

Cheers, Luke.

 

[Dieselman]

Just keep the engine ticking over with the expansion tank cap off and the heater full on. It will eventually bleed.
You might need a book to read or try watching some drying paint whilst doing this.

Did you drain the engine block, if not only about 5 litres will go in.

 

[lukebowman551]

How do i drain the engine block?

 

[lukebowman551]

You mean did i drain the block before i re-filled the coolant? I opened the drain plug at the bottom of the radiator and also took the oil to water heat exchanger off. I don't know where the block drain plug is so as far as i know i didn't drain the block.

I left the engine on tickover with expansion tank cap off and squeezed the hoses also heater on full. The air was bleeding out slowly but it got a bit late so i had to stop as i'm having to do it in the street. So far it's probably taken nearly 6 litres i reckon. The temp was sitting nicely at about 85 - 90 Celsius.

 

[Dieselman]

It sounds like it's full again but has about 3 litres of old coolant in there.

To drain the block undo the drain plug under the no6 exhaust manifold.