New guy here with a 240D. The 240 has 285k and smells of antifreeze when I turn on the right side heat. I have only had the car for a few months and it is the best car that I have ever owned. So far I have done the clutch master cylinder, upper control arms, lower ball joints, tie rods, and shocks all myself. (though I had to have a shop press in the lower ball joints into the steering knuckle)

Is the heater core a DIY job for me? It looks like they started with a heater core and built the car around it. Is the CD rom worth the $116 as a reference? Haynes does not cover the heater core.

Welcome to the world of Mercedes. Yes, Mercedes built the car from the heater core outwards. I broke a lever on the flap inside the heater core compartment and undertook to replace it. Took me almost two days. Everything must come out, including the AC, dash, blower, tubes, ducts, the works. Luckily I got mine reassembled with nary a screw left over. Thereis a separate heating and AC manual for the 123 series cars, and it was essential for me. Yes, a DYIer can do it and should, in light of the labor cost to have someone else do it, but it is not a job to be contemplated lightly. You will incur some expense in evacuating and refilling thenAC. Sujject you rehab the AC while the system is down. If the smell is only when the right side is operating, perhapes you will be luckt and find the problem short of the total removal.

__________________
Douglas
1959 M-B 220S cabriolet

My 240D heater core developed a leak some years ago. It is such an enormous job to get to it, I went to a lot of trouble and took a chance and was lucky enough to fix it without taking apart the dash.

Taking apart the dash is not only frustrating, but unless you really know how it comes apart and goes back together, you run a chance of making your Benz a rattle trap.

Here's what I did. I used some heater hose and a salvaged auxilliary water pump, a camp stove and a metal pot. I disconnected the hoses to the heater at the firewall and connected heater hose long enough to reach my bucket and campstove. I heated about a gallon and a half of water with a can of bars leaks added, I don't know how hot it was, but I made sure it didn't boil. I pulled this concoction through the pump and circulated it through the heater core for about fifteen minutes. I then disconnected the contraption and let it set overnight. In the process of doing this I drained the block and radiator and flushed as best I could. The next morning I connected the heater core and added antifreeze and water.

I think that was about eight years and a couple of hundred thousand miles ago. It has been fine since.

I went to all that trouble to keep from putting the bars leaks in my radiator. But, it may very work by just adding a can of bars leaks to the radiator, run it a week, then flush the system with water and freshen the antifreeze.

I was willing to take this chance, you may not want to. This is a personal decision and I offer no guarantees that it will work for you.

Best of luck,

Does the 1979 year model of the 240D have the auxiliary water pump? Certainly my 1977 version does not. I suspect they began in 1980.

__________________
Douglas
1959 M-B 220S cabriolet

No it does not have an aux. pump, only the climate controlled cars have them. The base a/c system does not.

I may have given the wrong impression. The car that I did the operation to did not have the aux. pump. I used one that I got off of a salvage car and hooked it up to the battery for power.

What would work better would be a pump from an old evaporative water cooler. These coolers are only used in very dry climates like New Mexico or somewhere. They have in them a pump that recirculates water across pads to humidify and cool the house.

Good luck,