Originally posted by 95E320cab
Had a new (rebuilt?) pump installed last week. When I picked up the car the indie had the hood up, the A/C on, and the car idling. The temp gauge was at 90C. The tech said "pretty good for idling for 45 min. with the A/C on". I agreed. However, I noticed driving over the weekend that the temp runs at 90C, without air on, around town. Before the pump the temp ran just over 80C. I was shocked to see the green coolant when I picked the car up, especially since I had gone to the dealer and bought a gallon of MB coolant before dropping the car off. Left it in the floorboard. Should I as them to change it out? Will it lower the operating temp? The tech said it was important not to mix the coolants, but that the green was okay. They did not change the thermostat out, only the serpentine belt.
The operating temp is not due to the green coolant necessarily probably, due to not mixing it correctly with water. A simple way of mixing it correctly is pour a cup of water and a cup of coolant after each other. Mxing by shaking both in a bottle is another mehtod also obviously. Another is that there is actually more coolant than water.. Air bubbles from intial fill have to be bled out. That is another possibiltiy. These are simple remedies.
The bad news is that it is required on your car to use only MB coolant or something equivalent due, to the aluminum heads, radiator, and other parts of the engine that consists of aluminum. Look in your MB owner's packet. Better backflush or flush the engine out of any remains of the green coolant.