Mercedes-Benz Forum banner

Coolant change = higher temp?

1640 Views 16 Replies 6 Participants Last post by  300se126
OK, feeling a little bit like an idiot here. Changed the two radiator hoses and the coolant last week and now have higher temp at idle and a slower cool down time while cruising. Used Pentosin coolant right at 50/50 but have noticed that while cruising temp is normal, right at 80c, at a stop the temp climbs rather quickly to right at 100 c and then when I take off it goes slowly back to 80c. Fans come on fine but I want to know what I did wrong with the coolant change to cause this because before old knucklehead (me) got his mitts on it it was fine, usually rock steady at 80c. Can air get trapped in this system and cause this? I let it run without the rad cap long enough after the thermostat opened but I wonder now. Any ideas? With hot Sacramento summer temps coming soon don't want to let the old girl get hot.
1 - 1 of 17 Posts
Sounds like an air lock - same thing happened to me. Try it again with the heater
on full and remove the overflow cap, leave the motor idle until the thermostat
opens and watch the bubbles.
1 - 1 of 17 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.