Thinking of purchasing a W124 with an M104 engine
 

I've been looking at various cars between 1993 and 1995, models such as a E320 wagon or 300E 2.8. All of my experience these past 15 years has been with diesels, so I'm feeling a little intimidated by things like the ETA, and MB's odd approach to engine codes. I know that I should check the wiring harness before purchase, and expect to change the head gasket eventually, although I've been told that the head gasket leak on an M104 is more of a superficial oil leak unlikely to mix with the coolant.

I'm good at keeping up on maintenance and anticipating problems before they arise. So the most important question I have is how likely are these cars to leave you stranded without warning? I've read about the OVP relay failing, and I know that the alternator regulator can crap out, but would a well maintained W124 be a reliable daily driver? Thanks

Ive had both m103 and m104 w124s and a m104 w202. The 103 car never gave me any issues but it was also a much nicer car owned by my mother. The second one had all the textbook issues and I sold it after my buddy ran it without oil.

The neutral safety switch, ovp, and anti theft issues can leave you stranded. Id suggest bypassing the antitheft and keeping a spare ovp and nss in the car. The wiring harness decay is very slow and its like your car has Alzheimers. I've only seen a m104 head gasket fail dramatically from a bad water pump. Losing reverse generally sucks too. I had the intake resonance flap fail at one point and it was dog until I replaced it.

Im not trying to be overly negative though. These are just the issues Ive experienced. The m104 is a really good engine. Its unfortunate they're all over 20 years old.

Biggest problem with the 104 is you'll get a ticket if you do more than loaf it along. And my 4300lb town car gets the same mpg. Great motor though, it's issues are pretty well documented. If I had to buy over I'd hold out for a diesel, or a v8 car.

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If you find a well cared for 124 M104, I suggest jumping on it quickly. My 93 300E 3.2 was amazing, 360K plus miles and ran strong! Rode and handled very well. I would not suggest using one in the snow, that was horrible.

Avoid ASR if you can, but don't let it be a deal breaker on a nice example.

Good luck!!!

The M104 is a really amazing engine in the W124 chassis, A freind of mine has it and the whipped cream smoothness is in a league of its own, even down to the sound it makes and it can really move once you boot it - yes you will get a ticket very quickly too.

I found one for $600 with a bad transmission..missing and loose spark plugs, full of mouse nests, they packed gravel up onto the valve covers and wiring trays..But once it was tuned up it ran great until the cyl head leaks got worse..It was a mercedes certified sold in 06 ofr just under 4K all perfect, but I discovered on doing the head gasket they had not torqued the last head bolt at all.

Once the head was rebuilt and with new gasket, the engine has literally leaked two drops in 20K miles..Burns one quart per oil change, or less..

There is a host of issues from fuel pumps with intermittent failure and electrical issues... but once sorted out the car will ALWAYS start. Be sure it has that Delphi harness labeled with the tag behind the battery. Its an awesome engine I wish one could still buy in a newer mercedes and nearly went to the BMW which does still offer a straight six with comparable MPG but less power..

Thinking of purchasing a W124 with an M104 engine
 

We're still driving our 95 wagon that I purchased in 2009. Absolutely hands down could not be happier with a 22 year old car than this one. It is driven every day. Garaged. I've done generally all my own maintenance - scheduled and preventative. My European shop I do some business with has told me that the head gasket is not something that is likely to fail - on mine. So, when tempted to look at something newer I just take it out for a drive and feel the smooth and quiet ride it gives and then put my checkbook back in my pocket!

If you are set on a later W124 sedan I would hold out for an E420. The M119 is lightyears ahead of the M104 in power and will get over 20 MPG on the highway. You still have the same electrical issues as the M104 but once replaced with non bio junk its great.

There's a thread that makes it seem replacing E420 power steering hoses is in league with 617 oil cooler hoses. Is that correct?

Sixto
98 E320s sedan and wagon

m104 last of the cast iron gasoline blocks,you can get over 1200hp with that motor.

How difficult is general maintenance on that car? I've never worked on anything newer than a 1981 300SD.

My M104 is my daily summer driver. Engine wiring harness, throttle body wiring, and head gasket have been proactively replaced. The engine has otherwise not been a problem and has never left me stranded.

On the other hand, the body electronics are horrible, a never ending battle with diagnosis and repair. It's shameful that Germans, who pride themselves in engineering, can do such a horrible job with electricals. If they weren't so parochially arrogant, they could study Japanese vehicles, reverse engineer the electricals, and copy the successful designs.... maybe even improve on them.

Who replaced that M272 intake manifold, then? :)

Sixto
98 E320s sedan and wagon

Pretty straight forward R&R job. I bent the injector rail in the process, and was lucky to find a used one with good injectors on CL.

The engine bay is rather cramped since the M119 is really squeezed in there but I didn't have any issues with plugs, wires, caps, rotors and oil changes. I also had to replace the upper wiring harness on mine and it was easier than the M104 I helped change a few years ago.