Tap into the heater hose coming from the block next to the oil filter. Use a T. Route that to your HE. Then, tap into the heater hose just after the aux pump (close to the water pump) with a T to your HE.

Arrange the T so that it will not interfere with getting the oil filter out, or you will regret it.

You will get heat to the HE without running the heater. Works for me.

Here is a post with pictures:
http://biodiesel.infopop.cc/groupee/forums/a/tpc/f/159605551/m/813107262/r/620101362#620101362

__________________
1984 300Sd 210k

Former cars:
1984 300D 445k (!!) (Strider) Original (and not rebuilt) engine and transmission. Currently running on V80 ( 80% vegetable oil, 20% petroleum products). Actually not, taking a WVO break.
1993 300d 2.5 275k. Current 120/day commuter
1981 300SD 188k (Hans) Killed by a deer