1994, C280: Expansion Tank Operation

[Arv]

Hello:

1. Is there some kinda valve at the bottom of the tank right where the hose
is connected which opens/closes when more coolent is needed in the engine?

2. If there is a valve, what triggers it to open/close? Coolent Pressure?

3. Also, is there a coolent pressure sensor on the water pump or somewhere
in the cooling system?

Thank you for your help,
Arv.

 

[xitrum_dalat]

the only thing to control pressure is tank cap.

if the pressure is higher than limit, it will release liquid out.

 

[Arv]

There seems to be something at the bottom of the tank at it's neck which I can see. If I put a wire or a snake, it doesn't go in the hose. It gets obstructed by something at the neck of the tank. Is this some kind of valve which opens periodically and what causes it to open?
Is it the pressure in the cooling system?

Thank you,
Arv.

 

[bigasotonuk]

Hi,
If you take a look at the link below, you will see your expansion tank and associated parts, and there is no valve on the bottom of the tank, just an opened ended hose attached by a jubilee clip. I think you may have a blockage.
http://www.detali.ru/cat/oem_mb2.as...GM=717.441&CT=F&cat=44V&SID=50&SGR=165&SGN=02

 

[Arv]

Thank you for the diagram. It seems that the diagram has 2 tanks, expansion and overflow which are seperate.

I will check tank ones again to see what's at the bottom. I will completely dry it out by putting in a piece of cloth and see what's down at the bottom.

My 1994, C280 with petrol engine has just 1 tank with seperate compartments for expansion and overflow. Am I right?

Thank you again for your help,
Arv.

 

[bigasotonuk]

Please bear in mind that the link I posted shows two diagrams, the right hand diagram is for Diesel's and the left hand one is the one fitted to your car.

 

[television]

As Andy,,only one tank and no valve, if too much water it blows it out, if too little it runs back in

 

[Arv]

Thank you all again for your help. I drained all the coolent from the tank and dried it out with a piece of cloth and I can see that the 2 chambers are connected by a hole at the bottom and the hose is connected right below that hole connecting the 2 chambers.

Thanks again,
Arv.