My Block Heater is Kaputt - PeachParts Mercedes-Benz Forum

aieeegrunt · #1 09-28-2013, 12:37 PM

Had a few chilly nights up here in Canada, plugged block heater in for several hours, didn't heat. Tried plugging it in all night, no response. Usually plugging the glow plug in results in a 7 second glow light on time. I have 1978 300D with the old school loop plugs. These nights it's been a 30 second glow plug light on time. Car still starts fine, but I will be in trouble once December comes. I'm planning on replacing the loop plugs with pencils some time in October, and I'll be going to some form of 5-40 oil as well.

My browsing of the forum leads me to believe that replacing the block heater is an unpleasant task.

Looking for alternatives, kicking around a few options

(1) Zero start or equivelant lower rad heater. Seems like it would be somewhere around a hundred or so for a new unit. Job will be mess, have to drain rad. Plus side is replacing the fluid can only be good for the car.

(2) Put a small electric fan heater in the engine bay. Bonus points if I can have it pointed at the air intake, so the car sucks warm air into the combustion chamber as I crank it.

(3) Wrap a batter heater around the lower rad hose. Is this even remotely smart?

(4) Mount a little basket to put a small flameless propane heater in the engine bay, something like a Little Buddy heater. Plus side is that this can be used to warm up the engine even if I can't plug it in. Downside is buying those little propane tanks all the time.

I suppose I could combine one of (1), (2), and (3) with (4)

Thanks in advance for the feedback

dude99 · #2 09-28-2013, 02:27 PM

Before you condemn the heater, it may just be the cord. Unplug the cord and test it with a multi meter. Same with the heating element. You might get luck and jut need a new cord.

If your looking for a cheep solution I seem to remember that a 60 watt incandescent trouble light, positioned nice and close shining on the head with the hood closed over night produced enough heat to warm the head for starting.

shadetree77 · #3 09-28-2013, 11:09 PM

don't do #4, plus those little buddies will only last about 3 hours on low

vstech · #4 09-28-2013, 11:27 PM

I can confirm a 60 watt shop light will start a 603 with no glow plugs in 0F weather... I put a METAL shield shop light on the EXHAUST side of the head and let the light shine on the exhaust manifold/head. car started up like it was summer time.
now, I know the 61x motors ESPECIALLY the loop plug equipped version is a totally different animal, and there is no "exhaust side" to the motor, there is a FUEL side, and an AIR side, and it'd be safe to set the light on the air side of the motor to start it up.

The Gears · #5 09-29-2013, 03:08 AM

I solved the block heater problem with a small boiler I put together from a copper pipe tee, two caps and a block heater that fit right into the copper tee. There is a 130deg furnace limit switch fastened to the top, the hot end, with JB Weld Putty.
The boiler is installed in the hose coming from the heater and into the side of the thermostat.
There are two brass hose barbs soldered into the caps.
The loop heating element is installed pointing down.
There is a bolt through the boiler that holds the heating element in tight against the gasket.
This thing will circulate a gallon a minute on bench test. Flow is through the engine and the cabin heater exchanger. Nice on a cold morning. If I plug it in when the engine is hot it won't come on for about an half an hour then the heating on time is on for twenty minutes and off or 30. this will vary on outside temperature.
My cash investment is around 65 bucks.

aieeegrunt · #6 10-03-2013, 01:35 PM

I'll definetly double check the cord! Thank you for that suggestion. The trouble light sounds like something I might be able to rig up with a portable power pack for the times I cannot plug the car in.

The other winterizing I am going to do is buying "pencil" adapter glow plugs to replace the loops I have now, if I can find a good price and a place that ships to Canada

Zacharias · #7 10-03-2013, 01:51 PM

There used to be a complete kit to convert to pencil style plugs, but I guess it isn't available anymore.

Have you seen this?

Mercedes Diesel Glow Plug Repair

Also this note from Kerry, in another thread:

Quote:

It's not a big deal. Buy 5 of the retrofit glow plugs. Remove the loop plugs and their heavy wires. Leave the ground wire at the front of the engine disconnected. Hook the wire that come from the firewall to the first plug near the firewall to the new pencil plug nearest the firewall, then make jumper wires to connect the rest of the new pencil plugs together. You're done.