Engine running temp
 

My radiator was professionally cleaned and I put the Zerex concentrate in. Car (1989 300SE) is running over the 80 mark on the gauge and closer to that next line. NOTE: Today was about 90 and I was running the AC. I just rebuilt the head due to overheating and blowing the head gasket. Car is running great, but I want to make sure that I don't overheat again since I am planning to take it on a 200 sojourn over the weekend. Maybe I am being paranoid, but I want to make sure all is ok.

87 degrees celsius is the standard opening point for most thermostats for that car, it sounds like the temp is close to normal. If the temp goes up at idle it is an airflow issue if there is an issue, if the temp goes up while on the highway with the air rushing through it is radiator related.

If you are in traffic and the heat is climbing too high get moving as soon as you can; but, in the interim turn the heater on full blast.

What ratio of coolant to water did you use? 50/50 or 1:1 is the most coolant that should be used. Coolant is not a good heat exchanger, water is better but some coolant, at least a 1/3 is needed.

RedLine WaterWetter is an emulsifier that works, I've used it.

If you do a flush/cleaning use CRC ThermoCure, great stuff.

Sent you a PM.

Sounds fine to me. Mine operated between about 87 and 93. But the gauge says 10 higher. The gauge is wrong as I've measured quite a few times with an IR thermometer.

Mine's got MB blue coolant mixed 50/50.

No worries.

RayH

All good to hear. I used the Zerex concentrate. I did drain whatever I could out of the system, put water in, ran the car and drained again. I was able to put almost one gallon of the Zerex concentrate in but no water to cut the solution. FYI As always thanks for the info.

Measure the freeze protection, 50/50 is -34F. If the freeze protection is lower than 50/50 it has too much coolant.