Hi there,

It is possible that your rad plastic tube that the hose connects to is cracked or broken.

I am assuming you mean the large rad hose - correct?

When the engine is cold, remove the air temp sensor and the air snorkle connected to your air filter housing. Now you can hold a clean plastic container under the hose at the rad as you loosen the clamp.

Carefully remove the hose allowing the coolant to drain into the plastic container.

you will see clearly if the plastic is cracked or broken or not. You will likely need a new rad. I replaced mine two weeks ago, also 1990 w124.

I'm in Richmond Hill, feel free to send me a PM and I can advise better.