Installing electric block heater

Installing Block Heater-reprinted from the Yahoo Sprintervan site in answer to someone who could not get the plug out :

The block plug you need to remove has a large 38mm threaded diameter with a 1.5mm thread pitch.
Even though there is only a shallow 4 or 5 thread width on the plug-
thats a lot of surface area. Regardless of whether MBenz uses a thread
locking agent or corrosion is present-heat is needed to allow easy
removal.

You should drain the area of the block that covers the plug
with coolant. The coolant provides a heatsink your propane torch
cannot overcome. The coolant drain for the block is just below and
forward of the big plug that your removing for the heater install. It
has a 17mm hex head and is easy to unscrew. Some later models may have
a built-in hose nipple in this plug to make draining less messy. This
plug will allow the coolant to drain to a level just below the "big
plug".

You can now use an acetylene torch to pinpoint heat at the
inner flange(the inner threaded portion) of the big plug. Propane make
be adequate as well, but theres a lot of heat transfer into the cast
iron block even without coolant.

Using the block coolant drain and high,
quick, pinpoint heat you can unscrew this plug with even a 12 point
22mm and no effort. Once out-don't forget to carefully extract the old
O-ring-likely stuck in the machined relief in the block opening. Doktor A

Thanks for the info. I will try to do it and keep you posted.
Looking at the engine I am a little confused now. There is a large plug on the right side of the engine (turbo side)in the back, and the draining plug is on the left side and there is a large plug there also. Which do I have to remove to install the block heater?

joska said:

Thanks for the info. I will try to do it and keep you posted.
Looking at the engine I am a little confused now. There is a large plug on the right side of the engine (turbo side)in the back, and the draining plug is on the left side and there is a large plug there also. Which do I have to remove to install the block heater?

Click to expand...

Looks like from what I saw on the yahoo sprintervan forum (Chrysler pdf there in links\diy help in the Bs), that's in on the turbo side. Lots more info there too.

Hi. Just wanted to clarify for the OM612 engine on an 02/03 that the freeze plug is the rearmost one on the passenger side (between cylinder 4 and 5) that needs to be removed. There seems to be two plugs on that side close together and the Temro/Zerostart instructions just say RR (rear right).
Thanks.

I had the dealer install a block heater on my '05 a couple years after buying it. Ever since then
when I brought it in for an oil change twice a year, I'd tell them that there's an antifreeze leak
somewhere. They supposedly put a tracer fluid in in and couldn't find the leak. After a few years
I gave up and thought it was nothing to worry about. A couple of years ago the mechanic
mentioned the o-ring on the block heater was leaking and it'd be like $200 to replace it. I was
like "DUH, I've been telling you there's a leak since you put it in, look at the work orders." They
wouldn't warranty it because it had gone so long.
FF to today when my friend and I are replacing the harmonic balancer, we're looking at things
and see the block heater clearly from the front top. We can see the o-ring is pushed out because
heater nut was over tightened.

So anyways, don't over tighten the nut or it will leak.

cousi said:

I had the dealer install a block heater on my '05 a couple years after buying it. Ever since then
when I brought it in for an oil change twice a year, I'd tell them that there's an antifreeze leak
somewhere. They supposedly put a tracer fluid in in and couldn't find the leak. After a few years
I gave up and thought it was nothing to worry about. A couple of years ago the mechanic
mentioned the o-ring on the block heater was leaking and it'd be like $200 to replace it. I was
like "DUH, I've been telling you there's a leak since you put it in, look at the work orders." They
wouldn't warranty it because it had gone so long.
FF to today when my friend and I are replacing the harmonic balancer, we're looking at things
and see the block heater clearly from the front top. We can see the o-ring is pushed out because
heater nut was over tightened.

So anyways, don't over tighten the nut or it will leak.

Click to expand...

This is exactly why I installed my own block heater myself .