Which Engine Block Coolant Hose Is Cracked or Loose?
 

1995 E320 / M104

REPOSTING THIS WITH CLEARER INFO:

Driving home last night I saw steam under the hood. After parking and opening the hood it was rising from the back of block from somewhere below the oil filter. The hood pad and the back of the plastic intake cover were wet, as if sprayed from below. Coolant level was about a pint low.

It appears I have a crack at the top of a hose since it does not leak when the engine is off or idling, but will shoot coolant straight up when rpms exceed about 2700 rpm, which I can see with the hood up and sitting in the driver's seat, revving the engine.

From what I can tell from my reading here, the possible hoses are the ATF collant (one of the two hoses is rubber??) or a heater-to-engine hose.

Am I missing any -- and is replacement straightforward if that becomes necessary (and if it is not just a slipped hose).

I had this happen to me (m103, but it's the same thing on the m104). It's your heater-to engine hose. If it was the ATF hose, the fluid would be red, and you wouldn't lose coolant. It's a straightforward, easy and inexpensive fix. The hose comes from the firewall on the driver's side, goes through a grommet in the partition between where the fusebox is and the engine compartment, and down towards the cylinder head. Feel with your fingers and a flashlight for wetness around the hose & the split. You can find the hose online, or you can go to your local MB dealer and they should have it for you next day, and for not much more expensive.

Great, thanks.

Even though sprays like a small geyser at high RPM, the coolant level is not dropping too quickly and the engine temp stays between 81 and 82C. And, as described, the spray is coming from below the oil filter, which is about where the heater hose apparently connects to the engine (though I can't see that from above and will probably have to get under the car).

Thankfully I noticed it yesterday since I can replace the hose this weekend.

Also -- is that the only hose? I was looking for the part in AllPartsExpress, above, and there appear to be two or three different hoses from engine to heater.

That is the heater hose. Replace that, and replace your upper and lower radiator hoses as well if you haven't already. A new solid hose puts pressure to other weak hoses and it's like a domino effect every week!!! trust me!!! New upper hose, then new lower hose, then new bypass hose, then new expansion tank!!!! Argghhhh!!!!! These are 20+ year old hoses and this car gets HOT!!!

Amen. That's all i got to say about that.

Thank you gentlemen -- it was exactly where you said and completely invisible until I squeezed the hose and coolant leaked out.