Changing antifreeze - general help please?

[tim.100]

Hello,

Have realised that having 7 year old antifreeze in my car is probably a bad idea, and would like to drain, flush, and refill this weekend.

Car is 97 W202 (post-facelift I think) 250 turbodiesel.

Questions:
- will I have to remove the engine undertray?
- is there a drain tap?
- is there a bleed screw, and is bleeding air out difficult to do? It takes an hour on a BMW straight six...


best regards,

Tim

 

[jimmy]

There is a tap on the near side bottom of the radiator, you need to take the tray off to get at it. Have the engine off but ignition on and heater on when draining and refilling. Fill slowly and you should be OK.

 

[1998K]

I try to help you as I can. Mine is a kompressor so not a diesel. There should be a plastic plug (red in my case) on below the radiator (left side in my LHD W202), there is also a metallic plug in the monoblock.

To access you take off the underside plasic cover, you clearly see the radiator plug. FYI I tried to operate also the monoblock plug but it has been suggested me to avoid (possible leakage). Draining out all the coolant from the radiator, then turn the key and operate (not starting the engine) the internal heat in order to permit also the drainage of the cabin heater fluid.

When you refill, start the engine with the radiator tank opened to permit bubbles to go out. Keep it till the termostat will open and if necessary refill with further liquid with engine running. I suggest to permit at least 10-15 min of engine running.

Should be quite completed, verify after few kilometers that it's all OK.

Hoping to help you, please consider an Haynes Manual if you need also some photograph and more detailed info on plug location and also to torque wrench setting (for the monobloch plug).

Hi

 

[guydewdney]

- is there a bleed screw, and is bleeding air out difficult to do? It takes an hour on a BMW straight six...

Try a V8 7 series beemer - a friend of mine spent three weeks topping up half a cup at a time (every other day) after we fixed the radiator... constant gurgling noises.. and that was after we spent an afternoon trying to bleed it...
(which is for sale now if anyones interested)

 

[tim.100]

Try a V8 7 series beemer - a friend of mine spent three weeks topping up half a cup at a time (every other day) after we fixed the radiator... constant gurgling noises.. and that was after we spent an afternoon trying to bleed it...
(which is for sale now if anyones interested)

Mine was the classic big 6 (M30) engine in an E32 730i - not quite weeks to bleed it, but I remember the neighbour's faces as I manoeuvred around the hill I then lived on to try and get it at the right angle for the air to come out....

 

[Dieselman]

There is a tap on the near side bottom of the radiator, you need to take the tray off to get at it. Have the engine off but ignition on and heater on when draining and refilling. Fill slowly and you should be OK.

There is a block drain under no5 exhaust manifold.

Ensure the heater controls are set to hot for both draining and filling. It will take about an hour of ticking over to bleed the system properly.

 

[MB250D]

Mine was the classic big 6 (M30) engine in an E32 730i - not quite weeks to bleed it, but I remember the neighbour's faces as I manoeuvred around the hill I then lived on to try and get it at the right angle for the air to come out....

Hehe - I've previously bought 2 M30 engined E34's for beer money, with "blown head gaskets". They both just needed parked uphill and bled properly, then they ran fine.....

 

[1998K]

Hehe - I've previously bought 2 M30 engined E34's for beer money, with "blown head gaskets". They both just needed parked uphill and bled properly, then they ran fine.....

this remember me when I found oil in the coolant circuit into my old BMW E34 M5, it was really a lot of money waste for a new headgasket.

 

[tim.100]

Thanks for the suggestions - the weather beat expectations this weekend so I didn't spend any time under the car.

When I do get around to doing it, will look for both drain plugs (block and radiator)

Best regards,

Tim