Changing Coolant & Hoses - '98ML320 - PeachParts Mercedes-Benz Forum

fema · #1 12-20-2004, 11:36 AM

Second year in a row I've found the lower radiator hose leaking at the clamp, last year tightning worked, but this time there was no room to tighten, so I figure I'll just replace all hoses and thermo, and flush. The car is an outdoor car and it was this time of year last when the same trouble occurred - so maybe some cold weather effects FYI.

That particular hose looks hard to get at the top point (on the water pump?) - is there any trick to getting there other than patience? Is the fan easily removed? I have a brush guard, which looks as if it were removed, would give me better access.

What's the best place to drain from? - I don't see radiator drain, and read somewhere about a block drain.

Thanks!

TBGeoff · #2 12-20-2004, 04:16 PM

Francis -- facing the front of the vehicle, the rad drain plug is at the lower left front of the rad. Don't look for a nicely finished brass fitting -- as I recall, the valve base is just moulded into the plastic plenum forming the side of the rad. The valve stem "handle" therein is a small plastic piece that is difficult to see. I ended up popping off the bumper cover to find it the first time the system was flushed. Shouldn't have to do that next time if I can remember how it feels.

Allthough I've never used it, I have a note here advising that the block drain is under the right hand exhaust manifold -- presumably this means passenger side of the block.

Good luck,

Geoff

fema · #3 12-20-2004, 06:39 PM

Thanks Geoff.

While on the subject - how important is it to get the hoses, clamps, and coolant from MB? To buy all is $388! I don't want to use poor quality, so let me know where to buy alternative parts.

Gilly · #4 12-20-2004, 07:32 PM

Try Fastlane for better parts prices and to help support this forum.
Yes, the radiator drain is on the FRONT of the radiator, lower corner passengers side, it looks like a red plastic wingnut. I would try twisting it counter-clockwise with a needle nose and a regular pliers, very tricky. You turn it 1/4 turn counter-clockwise, then pul "out" on it slightly. There is a small tube off to the side that the coolant runs out of.
The block drain, passengers side of the block, hard to see, it's a bluish colored metal. You use a LONNNG extension with an allen socket (6mm?) with a ball end on it, and the long extension in inserted between the top of the frame rail and plastic inner fender, almost need to remove the RF wheel to do it. The allen socket is inserted into the drain fitting and twist in the normal loosen direction (counter-clockwise), loosen about 1 or 2 turns, then remove the tool and the coolant flows out the hex shaped hole in the center (that you loosened the fitting with).
When the coolant is almost done runnning out, turn the key on and off briefly so the aux pump will run and help pump out more fluid.
I would re-use the clamps, just replace the lower hose.
No real trick to remove the upper clamp. I'd do it from the underhood area, not under the truck. Use a hex socket, short extension and 1/4" drive short ratchet, not a screwdriver.

Gilly

sdanville · #5 12-20-2004, 09:37 PM

Will the Mercedes take any quality anti-freeze ?
I know Honda tries and scares you into buying their $18 a gallon stuff.
(which I got scared into buying for my Honda's).

My Oldsmobile Silouette came with the Orange stuff and the dealer suggested the Green after a failed head gasket at 20,000 miles.

Gilly · #6 12-21-2004, 04:33 AM

I would have switched the Olds off of that "DexCool" crap too, I've had problems with it.
The MB you'd be well-advised to stick with the MB coolant however, good shtuff.

Gilly