Block Heater Wiring
on the 1995 E300D (W124/OM606)
by Chris W.
10/5/03
Let's Wire Up the Block Heater!
It's getting cold. If you have a diesel, that means that you might want to fire up the block heater. My '95 E300D is new to me. I did not know if it even had a block heater. A bit of research determined that it does, and I believe that all diesels from at least 1995 onward have block heaters. BUT...they are not wired, unless you or the previous owner took the car back to the dealer for the free heater cord install. (Canadians and the rest of the world - it may be different in colder climates.) Look behind the small removable rectangular section of your plastic front grill on the passenger side to see if the cord is there.
So, I looked, and my cord was not present. So I ordered one - it's cheap, as it should be. Here's how to install it. An easy one-beer job.
First jack up the front of the car, place your jack stands, and remove the plastic belly pan, if you still have one. This photo shows what you see when looking down from the top side. The heater is located on the passenger side of the engine block, below the exhaust manifold. It has a black plastic cap on it, assuming it is still there.
Because you are working next to the exhaust manifold, wait until your car is cold to do this job.
The cap was tight on my car so I used some slip joint pliers to grab it and loosen it enough to remove it by hand. It's a tight fit, but you can reach it from above without much difficulty.
This close-up photo was taken from below and shows the heater with the cap. Nice to have the close-up feature on the digital cam - and long arms to hold the camera where my eyes couldn't see!
This photo shows the view from the top with the black plastic cap removed - you can see the brass threads on the heater itself.
This photo is a close-up of the heater with the cap removed.
This photo shows the heater cord. 3 prong plug on one end, and two holes on the other to fit the prongs on the heater.
Now you have to get under the car, and plug the heater cord into the heater itself. A bit of feeling and dexterity required, but it is not too difficult. You have to do it pretty much by feel, because you can't see too well up there. Actually if you are adventurous, you could probably remove the second plastic belly pan and gain more access and visibility under the car, but I did not feel like doing that, and the job is not too hard with it still in place.
So now you have plugged in the heater, you have to route the cord out the front of the car. I have not seen how the dealer techs do it, but I chose to run mine along the transmission oil cooler line. I just zip tied it along that tranny cooler line about every 6 inches or so, no big deal. Then you snake it out of the front of the car, out the trap door in the front fascia.
Here is the last photo with the cord hanging out the front of my bug splattered fascia. Don't make the same mistake I did at this point. You have to secure the cord firmly in place so it can not drop down and drag on the pavement. Another zip tie or two should do it. I did not do that and managed to drive about 80 miles with the cord dragging! Chewed up the plug quite nicely, but it still works. Now go have another beer and change the oil while your car is nicely up on the jack stands!
- Chris W.
CategoryDiy
