Cooling Problem - PeachParts Mercedes-Benz Forum

NY2LA · #1 03-20-2007, 02:10 PM

Recently I was driving on the freeway and I noticed that my temp guage went as high as 120c but not into the red... the temp. outside was not hot maybe around 78*. I replaced the themostat and flushed the radiator and added new coolant... then took it out on the freeway again with outside temp at around 60* and the needle went from 40-89 in about 4-5 mins but never went above 90...
Someone made the remark that the radiator could be losing pressure around the tank seal. It is not losing coolant. I have not had to put coolant in the resevoir in over 2 yrs.
Is it possible for a temperature rise to be caused by a radiator that is losing pressure and how do I determine if that is my problem. Could there be anyother problem I am overlooking?

1982 300SD Turbo

david s poole · #2 03-20-2007, 02:34 PM

how old is that radiator?

NY2LA · #3 03-20-2007, 02:44 PM

I have to believe it came with the car originally... so 24-25 yrs old.

NY2LA · #4 03-20-2007, 02:48 PM

Hi David:
Thanks for your reply... I don't have any idea on how old... but I am going to say that the radiator is original... I can tell you this.. when I look at the top of the radiator, the tank part, are area where the tank is attached to the base it is damp all the way around.. but as mentioned I have not had to put coolant into the resevoir... it stays full... even when cold...

david s poole · #5 03-20-2007, 03:49 PM

the tubes in that radiator have shrunk[they are aluminum and start to shrink from day one usually last 7yrs]you will find that you have to race the engine to force enough water through the pipes to get normal cooling.also check the fan clutch as they are known for going bad.

mespe · #6 04-11-2007, 10:15 AM

You could have a leak in the damp area. Pressure test the system. If the leak is on the suction side of the cooling system, it'll draw in air, but not leak much coolant. Remember, a closed cooling system should lose no coolant.
With the leak sucking in air, you prol need to purge the air out of the system.

good luck