I have a newly-rebuilt engine, including a new engine block heater, on
my W123 300D. As it is no getting cold at night, I plugged the block
heater in, it worked splendidly ONE night, the engine started smartly
the next morning, and the block heater hasn't worked since.

Is there anything to look for or consider other than just a
prematurely failed block heater unit. Everything was new on this,
heater unit and wiring.

Thanks!

"randallbrink (AT) mac (DOT) com" <randallbrink (AT) gmail (DOT) com> wrote

On Oct 4, 2:54*pm, "Chas Hurst" <hur... (AT) comcrap (DOT) not> wrote:
Yes, I checked the electrical outlet, and it seems to work normally.
The block heater is not on a an car circuit, i.e., no fuse, etc.

"randallbrink" <randallbrink (AT) gmail (DOT) com> wrote

On Oct 4, 2:54 pm, "Chas Hurst" <hur... (AT) comcrap (DOT) not> wrote:
I'm quite familiar with the Benz block heater.
Get out your volt-ohm meter and start checking. I think the heater element
drawsa bout 500 watts, so the resistance of the heater should be around
20-22 ohms.
The power cord attaches to the block unit using a knurled threaded collar.
It's possible that wasn't made secure on assembly. I've seen the power cord
develope an internal break too.

On Oct 4, 4:03*pm, "Chas Hurst" <hur... (AT) comcrap (DOT) not> wrote:
Thanks very much. This is the type of thing I expected, particularly
with the unit appearing to fail so soon after installation. I'll get
to work on it with the meter.

On Oct 4, 4:03*pm, "Chas Hurst" <hur... (AT) comcrap (DOT) not> wrote:
Wire dead.

"randallbrink" <randallbrink (AT) gmail (DOT) com> wrote

On Oct 4, 4:03 pm, "Chas Hurst" <hur... (AT) comcrap (DOT) not> wrote:
That might be a replacable cord if you don't care to repair it.

On Oct 7, 6:57*am, "Chas Hurst" <hur... (AT) comcrap (DOT) not> wrote:
I am going to try to replace the cord today, but unfortunately, it is
one piece with the block heater and no way to detach the cord from the
heater unit, making the repair more difficult.

On Oct 7, 8:18*am, randallbrink <randallbr... (AT) gmail (DOT) com> wrote:
Actually, it turned out that it was NOT the cord, but the block heater
itself that had failed.

On Oct 7, 8:18*am, randallbrink <randallbr... (AT) gmail (DOT) com> wrote:
Also, in deference to an earlier poster, I want to correct myself on
an earlier post--the Mercedes Block Heater cord DOES detach from the
back of the unit, and I did not see this until I removed the air
cleaner pan and was able to get at the actual block heater unit.
Sorry for the mis-statement.