Hi all!

This morning I checked my coolant level on my '90 190E (cold). I see that the level is about 1 inch from the "arrow pointing at the line" mark. I remembered during my last major service, the tech told me to add water if the coolant level is a little low. Using a styrofoam cup, I poured about 8-10oz of (filtered) water into it and then poured it into the resevoir. I then decided to add some coolant. Again, using the same cup, I poured about 5-6oz of M-B orange coolant into it and then poured the coolant into the resevoir. The coolant level was now just slightly above the arrow mark.

For some reason after I had done this, I remembered something about how styrofoam cups tend to melt, degrade, or deform when they come in contact with certain chemicals. I immediately inspected the cup I was using but didn't see any degradation or deformity. The cup looked and felt no different than in its unused condition.

I used a styrofoam cup because it was disposable and allowed me to eaily add water/coolant without spilling. Does coolant have any effect on styrofoam? And is it SAFE and OKAY to pour coolant into a styrofoam cup and then pour it into your resevoir? Thanks in advance.