PeachParts Mercedes-Benz Forum - View Single Post

crhenkel · #9 09-24-2007, 09:45 PM

It really doesnt matter I would say.
You have a new radiator and thermostat, you are not losing any fluid from a bad head gasket or any leaks, there is not much more you can do to get the engine to run any cooler. I guess you should have the mech make sure the aux fans are coming on and off as they are supposed to and that the temp sensors are all working as they should. But after that it the car is getting air and the rad and therm are new, it is likely your car is running at its Max cooling capasity right now. It is not the end of the world running ar 90-100 as long as that is where it likes to stay. The big thing would be to see if it cools down while on a highway trip in moderate weather, say 85-90 max hi temp outside. If the car cools down to a average of 90 c then it is going to be fine. All cars like to heat up when not moving and the outside air is already hot. I have had my small 190E engine temp at 100 to 110 easy sitting and idling in an enclosed garage ( no, I vent the exhast outside) and it was winter time outside.
I would buy a new radiator cap, get which ever one you want and use it. I would say that if the 140 is the one for sale on line everywhere it is likely because at some point MB determined that they wanted to use the 140 and they now recommend the 140. I have seen that on several diff MB models. Mine has a sticker right on the reservoir that says use only a cap with 120 marked on it, but the dealer will sell you a 140 every time because that is the new part number that the old part was changed from in my car's case. I would bet yours was changed too in the parts lisst at some point. the online sales shops are not making anything up, they simply go by what the parts list at now, I would say that the 140 is now listed at the correct cap. Have the dealer run the part number or look up what cap they would order, it is probably a 140, eitehr way, it really wont hurt a thing.