where is my engine block coolant drain plug? 4.2 V8 - PeachParts Mercedes-Benz Forum

Two560Two · #1 12-03-2005, 10:37 AM

After looking through all the MB books I have, the books dont seem to point me to the coolant drain plug on the engine. Its a 420sel and cant find it when Im looking around the engine bay and under. Can someone plz help

MikeTangas · #2 12-03-2005, 10:58 AM

Should be able to find them from under the car. There should be two, one on each side of the block. Look in the area between the motor mount arm and front of the block, they should be about 3/4" diameter and take a hex wrench, 6mm I think.

Two560Two · #3 12-10-2005, 08:59 PM

found it! Thanks. Another question. Now since I can only add coolant through the expansion tank, how can I tell that I am putting the correct mixture of coolant and water with out prmixing it in another container? My darn books are all in liters and I am not too great with math and conversions. I just wish the books also listed gallons and quarts.

MikeTangas · #4 12-10-2005, 11:04 PM

I pre-mix my coolant. Pour the majority of it in through the upper radiator hose, top up the remainder via the expansion tank. Make sure to have the heater turned on when you run it to purge the heater core of air.

For pre-mixing I use Prestone Radiator & Battery water. Using an empty coolant jug I pour 60% water to 40% coolant ( a little more than 1/2 gallon and a little less than 1/2) and shake to mx. Before pouring in I'll check the mix with my hydrometer to make sure I'm about 60/40 to 55/45 for opitmal protection. That mix was great in the California desert and has done fine in the frozen north.