560SEL Heater hose replacement completed
I just had one of the heater hoses from the engine block split and cause me to lose all coolant so I took the opportunity to replace all four hoses. These hoses are difficult to remove and refit so it's well worth doing them all at the same time, it makes it easier to get to do the job if you replace them all. I always start at the difficult end first which in this case is the ends in between the two firewalls. The only tools I needed were an 8mm socket, a long handled screw driver, and a sharp knife.
First up remove the rubber strip that sits along the top of the first firewall, this just pulls up and off and then pull the ABS computer up and out of it's holder, this is just an interference fit so pull straight up. Secondly there are three 8mm bolts and a clip that secure the middle section of the first firewall, remove these and the middle section pulls up and slightly towards the front of the car to remove.
With these things out of the way you will now be able to see all the hoses, the two that come from the left and right sides of the engine block through the firewall, and the two that are inside the firewall and run from left to right. The ABS computer bracket is a pain as it prevents easy access to the hose clips, luckily only one couldn't be reached with a screw driver and was relatively easy to get to with a ring and open ender. Once all the hose clips were completely undone and slid off the hoses I used a sharp knife to cut the hose open at the end. Trying to pull these hoses off is very difficult as there is little room and with age they are generally stuck. With the hose cut they slip off much easier. The ends on the engine block couldn't be reached with the knife but there was enough room to simply pull them off. There is a T piece that the hoses connect to in between the firewalls, this needs to be unbolted to get easier access to the hoses.
Replacement is reasonably simply, fit the two engine hoses first and then the others. Ensure that you have the hose clips in the correct way so that you can easily reach them with a long handled screw driver to tighten them. Before refitting the middle firewall section test the cooling system for leaks.
Hope this helps someone, sorry about the lack of pictures but I didn't have access to a camera at the time, and was under some pressure to get this fixed. The hoses were about $50 us all up.