Engine Head Gasket Replacement?
 

Hello,
I have a W124 300E 1989 and need some advise
for the below case: :the radiator has been checked under pressure and holds
up to 4 Atm- and is leak free, the heater has been disconnected
all engine coolant hoses are brand new. I am getting engine coolant leaks
that are iritating to the eyes when the engine worms up.
Could the engine coolant be emerging from the head gasket unnoticed, there are bubbles of air coming out in the compensating engine coolant container any way of testing this
other than dismantling the engine?
Michael

The bubbles in the coolant reservoir are enough test for me. You can try a leakdown test if you're not convinced. If you don't have a leakdown gauge, pressurize each cylinder to 100psi when it's at compression TDC and check for bubbles in the coolant reservoir.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

Happened to me, bubbles in the reservoir=blown head gasket.
Be a good time to replace seals.