w 140 question
 

hi.. i need some help i have a 93 mercedes 300 se and im having problems with it running a little hot, its running at 100 degrees and the little tank is overflowing i can see steam comming from it, also i was thinking it was the thermostat so i remove it and its still running hot, it takes a while to get hot not real fast, and no water in oil no oil in water so my question is what do i check for next and thanks again for the help.

that's a good one...all I can think of is put a new themostat in and properly bleed the system...although 100 is not critical in the overheat thing......are you sure the cap is properly secured on the little tank? You might want to make sure of that first, before going ahead with other things.... sounds to me like that is your problem...the overflow/filler tank cap is either not re-installed properly or (unlikely) faulty...just a guess mind you

+1 on the filler cap The system has to run under pressure to prevent a boil over.

How's your fan clutch? The silicone goo can drain out over the years and leave the fan to free-wheel on the shaft. Give it a spin by hand and see how easy it is.

Last thing: When's the last time you changed your coolant? It might not be a bad idea to test it with a hygrometer and make sure you've got a 50/50 mix.

w 140
 

ok.. thanks for the replys i will check the fan clutch today.

You might want to check the radiator. Over time radiators can lose their cooling ability. This can be due to internal clogging or dirt/debris clogging the cooling fins. If I were you I'd check the radiator and see what kind of condition it's in.

easiest way to check the fan clutch is to spin the fan by hand when the engine is stone cold...it should spin freely...if it doesn't then the fan clutch is locked up.....

Actually it SHOULDN'T spin freely. You should be able to feel some drag from the silicone fluid when you spin it. If it spins freenly that means all the silicone fluid has leaked out and the fan won't be able to move air effectively.