testing a block heater? - PeachParts Mercedes-Benz Forum

galu220d · #1 02-05-2007, 03:45 AM

not sure if my block heater is working.
is it possible to test the thing without removing it?

i've had it plugged in overnight with no apparent benefit.

#2 02-05-2007, 03:50 AM

Get a multimeter and check it's resistance (Ohms/continuity) at the plug. Also make sure the plug is actually connected to the block heater.

pawoSD · #3 02-05-2007, 04:01 AM

I always check mine for operation with a Kill-a-watt meter....just plug that in, then the extension cord into it, and it says the exact watts/amps that are being used....my hose heater draws about 2.93 amps when warmed up...just over 3 when first plugged in. Equates to around 345 watts....it gets HOT. I burned myself before feeling under the car to check if it was on.....thats when I switched to using the meter...

Shawn D. · #4 02-05-2007, 09:34 AM

Quote:

Originally Posted by pawoSD

I always check mine for operation with a Kill-a-watt meter....just plug that in, then the extension cord into it, and it says the exact watts/amps that are being used....my hose heater draws about 2.93 amps when warmed up...just over 3 when first plugged in. Equates to around 345 watts....it gets HOT.

I use a La Crosse Technology 3362U and it shows my block heater on my '84 300td using 430 watts.

wheelguru · #5 02-05-2007, 11:53 AM

I just stick my head down by the grill and listen for the sound. You can hear the heater as it warms up. takes about 3 seconds after you plug it in. I would describe it as a roar, but really faint. I have had to replace the plug end of my heater before (the part that sticks out from the grill).

#6 02-05-2007, 12:22 PM

Quote:

Originally Posted by wheelguru

I just stick my head down by the grill and listen for the sound. You can hear the heater as it warms up. takes about 3 seconds after you plug it in. I would describe it as a roar, but really faint. I have had to replace the plug end of my heater before (the part that sticks out from the grill).

I can also hear mine when it is energized. It sort sounds like something starting to boil on the stove. I assume there is some local boiling of the coolant arounf the heating element.

Whiskeydan · #7 02-05-2007, 02:13 PM

You should also be able to hear the connection being made when you plug it in. A faint "click" at the plug indicating current is flowing.

irhunter · #8 02-05-2007, 02:53 PM

Does someone know what the resistance of the heater should be?

Roy

larry perkins · #9 02-05-2007, 03:35 PM

i normally see 15-25 ohm,depends on the temp
larry

irhunter · #10 02-06-2007, 05:07 PM

Thanks, Larry.

Ken300D · #11 02-06-2007, 06:14 PM

The block heater won't work if the line cord plug is dirty or corroded - as may be the case if you haven't used it in a couple of years. Get out something to clean the 110v contacts down to shiny metal.

Then when you plug it in, go away and come back in five minutes or so. With the hood up and your ear down by the turbo U-tube, you should hear a hiss just like a hot water heater makes when its heating water.

Ohm meter should show low ohmage and not an open circuit.

Ken300D

Sbean · #12 02-06-2007, 08:07 PM

Mine ('80 300 TD) makes the sizzling sound within 5 seconds of being plugged in. My other '80 300 TD doesn't have a block heater. Steve

longshore1 · #13 02-07-2007, 06:50 PM

I posted this topic a few weeks ago and got only two responses. I think mine is not working, but the car starts right up on 10 deg days. thanks for all the info.