Diesel Block Heater

Oct 04, 2009 23 Replies

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!


Did you check the circuit you plugged the heater into?

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.

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.

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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.

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Wire dead.

That might be a replacable cord if you don't care to repair it.

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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.

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Actually, it turned out that it was NOT the cord, but the block heater itself that had failed.

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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.

Since you had the car rebuilt, take it back to them and have them change it out for free...

Another $120 bill.....

But it works now!

I am at a loss to figure out what would cause the heater to fail after one night, but it is in keeping with my good fortune with this car.

At this rate your fortune may not stay good...

DAS

To send an e-mail directly replace "spam" with "schmetterling"

That heater should have been under warranty. Fortune? Hah... until your second one dies... but otherwise, thumbs up!

The block heater was the last component on the engine to be replaced. Everything under the hood, except for the radiator cap, has been replaced, and I'm hoping to get at least 200-300 miles out of the car before I have to start replacing things again...

200 to 300 miles? Your expectations seem exceedingly low. I have been following your travails with astonished incredulity. I thought Der Klunker was bad. I was about to abandon it the other day when the battery turned up dead. But the dome light had been left on for several days. Nonetheless, the next time I am facing a $400+ bill I will simply hand over the keys to whomever wants to charge me that. Totally undependable transportation is no transportation at all.

Did I tell you about the gear shif lever separating itself from the transmission? I think I did. A vise-grip wrench worked very well.

While I was joking, of course, about the 200-300 miles, it makes it even more ironic that, when I went out to the car this morning, the radiator had failed, spilling and emptying its contents during the night. The only mileage I got out of the car was the 3 miles from the shop to home.

Replaced leaking radiator hoses and clamps.

Second new engine block heater has failed.

"At this rate your fortune may not stay good..."

DAS

To send an e-mail directly replace "spam" with "schmetterling"

Jeez! Second heater failed? Must have been lack of coolant. How long did you heat up your engine? Are you sure your outlet is 115V?

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