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<small-six block coolant drain plug>

Thi VanAusdal said:

>Someone asked about draining the coolant in his 2.0 baby six, saying
>there was no drain for the block...
>    I have just run out into my garage in my skivvies to confirm for
>all of you:
>
>            There is!!!
>
>    It is on the exhaust side, by the #5 cylinder, a 17mm or 19mm hex
>head bolt.  Its location is similar to the big 6 and 4-cylinder blocks.
>It is the rearward part of the block to allow complete drainage of the
>cooling jacket.  Look again: it is behind a "ridge" in the block that
>is an oil drain for the cylinder head.  The plug is just below the
>level of the freeze plugs.

However, be aware that there may still be as much as 4 to 5 quarts of
coolant remaining in the system (of an E30, at least) even after draining
the block and radiator.  A well-done coolant drain, flush, and refill
therefore can take quite a while, since one should allow the engine to heat
up to the point where the thermostat opens to get complete mixing and
exchange of fluids.  One is well-advised to allow the engine to cool off
significantly before removing the block coolant drain!

While recently changing coolant in our E30, I flushed the system.  The
"flushed" coolant was a pale yellow as a result of the several quarts of
coolant remaining in the system.  So each step should be done twice, and,
when refilling, one might be better off to add all the antifreeze required,
since you can't tell exactly how many quarts of coolant you'll be able to
get back in.

Paul Reitz
BMWCCA #1167