Cali300E

Vehicle is a 1987 300E. There's a very short (couple of inches at the most) hose between the head and the thermostat (I'm assuming it's the thermostat..), front of engine on left side. My hose is cracked and starting to leak. But it doesn't look like there's enough room to squeeze a new hose in there. Before I destroy this hose taking it out, I want to be sure I can get the new one in. Do I need to take other parts out first (like that thermostat - or whatever - housing)? Also, is Zerex G05 right for this engine? Time for a coolant flush, too!

-- John
John F Sandhoff sandhoff@csus.edu Sacramento, CA

NorCal124

No not zerex! Zerex is more for Toyota, VW, Volvo, Audi, etc. Stay w/ the dealer stuff as much as possible. I see you're from Sacramento, I go to school up here. Glad to meet another W124 enthusiast.

AMG_Eric

1st go to the dealer and get the hose. it connects from the water pump to the front of the head. the thermostat doesnt have a hose fitting.

once you have the CORRECT hose then remove it. it will leak a bit. i just did mine. just use water unless you are going to the mts where it snows. you wont lose that much coolant. make sure you have a drain pan under the car so it doesnt puke all over. also buy 2 new hose clamps. it wont hurt. use caution when working close to the neck fo the radiator it is made of plastic and CRACKS really easy.

CDP

Yes, becareful with the neck of the radiator since it's made out of plastic. Don't over tighten, obviously. If you have the updated OEM radiator with the reinforced neck that has the metal ring on the inside then you're okay.

Cali300E

Sounds like you're referring to the upper radiator hose? The hose I have a problem with is the really short one that connects the pump/thermostat to the head. After staring at it for awhile this weekend, I'm convinced I'm going to need to pull the water pump to replace it. Somebody tell me I'm wrong...

Should I replace the pump as long as it's apart. Opinions? Favorite MB parts places? (Geez, the local dealer wants 25 bucks just for a gallon of MB antifreeze!)

oliverb

Hi;
YES, the Zerex G5 is the antifreeze you want. This formulation has been made by Zerex for many years specifically for such Euro engines and is approved by MB for use in your engine! Officially recommended on the MBCA website. I believe I read that Zerex may be/has been the O.E.M. supplier for MB coolant, with a slightly different dye additive. The Zerex is somewhere between $12.50 - $15.00/gallon, depending on where you but it. I ordered mine from a NAPA store - most places that carry Zerex do not carry the G5 formulation.
OliverB

ShoreBenz

No, you do not have to pull the water pump, & the radiator is not involved. Just replace the hose with a OEM hose & clamps. Check the condition of the thermostat housing as it may be cracked or worn. It is an inexpensive part.

Cali300E

Okay, I know I'm beating this to death.. I'm sorry. This hose connects to the pump, below the thermostat housing. Pulling the housing doesn't affect this hose. I haven't pulled the old hose yet 'cause as soon as I try there's no going back (nasty crack in it, any flexing will tear the hose all the way) so I don't know exactly how much space is between the pipe coming off the head and the fitting on the pump. Looking at a picture of the water pump, these two pipes must be just about touching and I just don't see how there's enough gap to wiggle the new hose in (yes, I have an OEM from the dealer). If I can, of course that would be wonderful, but I just can't envision it working that way.

So I just need to brace myself for a potentially ugly weekend. From what I can tell, a pump R&R is 7.5 hrs for a trained mechanic with the right tools. Ugh.

It's only a 'little' broken right now. I know I have to fix this before it blows on the freeway, but I don't want to take it apart and find I'm stuck, either.

Thanks for listening... words of encouragement welcome...

ShoreBenz

Simply replace the hose & clamps.