E420 Engine to Heater Core Hose
 

I noticed a leak right at the elbow on the left (driver's side). It looks like I'm going to have to replace this line (124 830 74 96) (attached). Has anyone done this? Access to where it goes into the heater seems simple enough, but it looks like I may have to take some of the plastic cowling off at the bottom of the windshield (in front of blower motor) to get to the two lower connections between the engine and firewall. I didn't see any hose clamps down below, but the epc shows two "rubber rings" (124 832 96 93). Are these just push-on fittings? Thanks.

Follow Up
 

The two rubber rings were just rub protectors for the hose, like the rings used on the 3/4" hose leading to the coolant recovery tank along the right fender well. My car didn't have the rings anyway, so I didn't install them.

Hose clamps are used for all three connections. The large hose runs vertically down past the back of the head on the driver's side and there is a PVC heat sleeve on about 6 inches of the hose in that area. It wasn't on the factory replacement hose, so I had to cut the old hose in order to slide it off. It was fairly brittle and I had to use lubricant to slide it in place on the new hose.

In order to access the hose clamps, I had to remove the cowling at the bottom of the windshield on the driver's side (just as if you were going to change the air filters). A 1/4" drive with a 12" extension works well to get to the hose clamp bolts. There was minimal coolant loss when I pulled the hoses off. I did knock loose a few vacuum lines from that yellow 3-in-1 connector at the firewall, but they slipped right back on. The factory hose was $67. It took a few hours. Overall, not a bad job. I plan to do the hoses on the passenger side next.

Maybe I should order them now and put them in the truck, so the hoses will never blow.