[Kirali]

Need help from the experts....

Just recently changed my water pump on my 1984 500SEC. The car has been running hotter than ususal at around 90-95c and in traffic fluctuates. I also noticed aftera 25 miles drive today while the car was running that the colloant level on the expansion tank was low but as soon as I turned the car off it filled up to normal levels.

Any help would be apprecaited.

 

[Mike NZ]

Did you change the thermostat at the same time, they come in a variety of operating temps.
Mine is 82C, and does fluctuate from there to 95C and back on occasion but for the main part stays on 82C.
Also, could there be an air lock in your cooling system ??

 

[DrewPT]

Kirali,

The coolant fluctuation is normal from when the car is hot vs cold. Also, there may be air pockets in the coolant, but they may have let the car run/coolant circulate after the water pump change.

I had mine done 2 weeks ago, and also had a new thermostat and hoses installed while they were in there. The normal temp went from 90-93C down to 83-85C, about what others on the forum told me to expect. It could be just the new thermostat, and maybe the temp was actually the same earlier. I also switched from conventional green coolant to Mercedes clear-orange, so that could have played a role.