I have been servicing my father's W124 '93 E320 coupe (3.2 M104) for him. One thing he wanted me to look for was the source of the oil leak under the back of the motor. You guessed it! Rear, right corner of the head gasket. Nothing in the coolant yet, just a slight annoying external leak. I don't know how long before it really will need attention. Our '90 300TE (3.0 M103) went for a couple of years with a worse leak than this before oil appeared in the coolant and I had to pull the head. That was when the car was about 10 years old with 145,000km. Early this year I helped my brother do the head gasket on his '92 180E (1.8 M102). 11 years old and 93,000km. Now the E320, 11 years and 136,000km. There almost seem to be a predictable pattern to this. Just as well I purchased my '90 190E 2.3 at 13 years and 211,000km with the head gasket previously replaced. Hopefully I won't have to do that one as well.

For those who are familiar with head gasket replacement on the M102, 103 and 104, how do they compare? I have done the job on the M102 and 103 and apart from the occasional stubborn item, the jobs were not difficult. How about for the M104? Any tips? I found with the 102 and 103 it was easiest to lift the head with exhaust manifolds attached but with inlet manifold left behind in engine bay. They are KE whereas this 104 is HFM so that might change things. I suspect my father might ask me if I can do the job. I have yet to break the news to him. I am getting to know his car well. This year alone I have done the water pump, belt tensioner and damper and have just finished fitting new front discs and pads in addition to a routine service. The car now travels only about 10,000km (6,000 miles) per year.

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107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.