Coolant flow to the WRD

[wwheeler]

Can anyone tell me which of the two coolant lines FEED the WRD thermostat? The top hose attaches to the head via a bolt on block and the bottom hose attaches to the coolant pipe that goes to the air intake to warm it up.

I am refilling my coolant and like to disconnect one hose to bleed the air out of the WRD.

Thanks!

[Rolf-Dieter ✝︎]

Perhaps you like to have a reed of this in the Technical Manual ----> http://www.sl113.org/wiki/Cooling/CoolingSystem

Make a search once the link opens on "bleed"

[garymand]

Hopefully the newer thermostats fit the 230.  the 250 and 280 have bleed valves built into the thermostat.  No worries about trapped air if your our car's mechanical condition is kept up.  I just recored my 250 radiator and could hear the air bubbles coming through the thermostat.  You can close the cap and squeeze the radiator hoses to move the water a little quicker, but it still takes a few minutes.  Just start the motor, cap off, heater on, when the thero opens, water will flow and level out.  Then you will know how much to add.

[Rolf-Dieter ✝︎]

Also have a look at Technical Notes Vol. 5 No 4 .... excellent information here ---> http://www.sl113.org/wiki/uploads/Restricted/PNv5i4US.pdf

[wwheeler]

I read the information in the technical notes below and just wanted clarify so I don't make a mess.

"Disconnect the top hose on the warm running device (WRD) of the FI pump (see
diagram on previous page and photo on next above). Continue filling with the pre-mix of
anti-freeze until water emerges from the top hose of the WRD and from the brass entry
point on the firewall. This should clear all air from the system."

Where do I disconnect the top hose for the WRD? Leave the hose on the WRD and disconnect from the pipe or the reverse? I want to capture the coolant and want to make sure I am waiting with a cup in the right spot. I did it wrong last time but do not remember what I did.

Thanks.

[wwheeler]

Threw caution to the wind. And the answer is......

Remove the top hose off of the WRD tower leaving it attached to the pipe attached to the coolant block which is mounted to the head. Put a cup under the end of the hose and pour coolant until it starts coming out. Bleeds most of the air from that area.

[Benz Dr.]

I'm not sure why you are doing this. Normally, this whole area is self bleeding.

[wwheeler]

On my W111, when I changed the coolant, The WRD would not warm due to air lock. The engine would run at full cold mode despite the engine being fully warm. Once you shut it off, the air will eventually bleed off. But the first start and possibly the second after that are affected.