M104 Engine Longevity Question
 

I have a M104 3.2 with 182K miles. From what I understand, the M104 does not need valve guides as often as the M103 engine.

So my question is, besides the engine wiring harness and head gasket, how long will a M104 last? What fails?

221,456.65 miles.

The only thing I can think of is the engine can overheat because of the radiator neck problem, water pump failure, or head gasket failure.

How many miles have you personally put on it? Do you know the history of the car? I've had to replace the water pump and the fan clutch bearing (typical at 200,000 miles I'm told). Belt tensioner goes too. I'm at 209,000 miles and bought it with 66,000 miles 5 years ago.

What other major work have you done in the last five years besides what you listed? Thanks. Just curious.

I bought the car with 179K miles this year so I've only put a few thousand miles on it. It had the headgasket replaced 3 years ago, the radiator and thermastat replaced this year and the engine wiring harness will be replaced soon.

I don't really expect people to accurately esitmate when my engine will fail. It's just that I have seen M103s that have died or that have terrible oil consumption but every M104 that I have seen has been alive and kicking.

I'm curious on this, too.

The M104's haven't been around for that long. The
"modern" HFM-SFI M104 was first used in the U.S. on W124's in 1993.

That's only 11 years.

I'm sure there are some with over 200,000 miles or more, but you don't see that many on this forum.

[QUOTE]Originally posted by suginami
[B]The M104's haven't been around for that long. The
"modern" HFM-SFI M104 was first used in the U.S. on W124's in 1993. That's only 11 years.

I agree with the point but the first application was actually the 1992 140 body, which was slightly misbadged as a 300SE.

It was also installed as a 3.0 version in the 1990 300CE.

Those were CIS rather than HFM.

That is correct. However, I think the durability will be the same regardless of type of fuel injection method.

Getting back to the original question: outside of non-engine related things like tracking down a phantom slow coolant leak my engine with 209,000 miles has no other engine noise than what's suppose to be heard and burns or leaks very minor amounts of oil. It is a very strong engine. I change the oil a lot too, by color as well as mileage. If I don't like the color of it - it's changed.

[QUOTE]Originally posted by deanyel
[B]I didn't include the early 3.0 liter M104's on the 300CE's, and the 1992 300SE because they are not HFM-SFI. The early M104 used the old mechanical CIS-E fuel injection, and the 3.2 liter in the 1992 300SE was an LH system, used only for this one year.

I believe it makes a difference in the long term reliability of the engine.

The HFM-SFI fuel injection system (hot-film mass air flow sensor) is fully electronic, with integrated electronic ignition and sequential fuel injection. This system combines fuel injection and ignition control in one module.

HFM fuel injection systems are designed so that idle speed can't be adjusted. Idle speed is completely controlled electronically. This HFM injection system also has adaptive technology that compensates for conditions such as engine wear and unmeasured intake air and is designed to maintain driveability as the engine ages.

HFM-SFI can retard engine knocking to just the knocking cylinders, unlike EZL technology, which retards spark timing across the entire engine. This keeps the ignition timing point as advanced as possible for maximum power output.

Wow, Paul, how do you know all this stuff? Where do you (and other senior members on this forum) find the time to have such scope and depth on MBs?

It depends on what you are refering to...

My 108 with the old M130.920 lasted 260K+ with the valves only being done once. It was starting to blow some more smoke when I let her go, but I am sure with another valve job she would have kept going. That was with MB technolgy from 1970. I would guess a properly maintained modern MB engine's bottom end would last over 300K. Maybe a search through one of those "who has the most miles" posts would lend some insight...