Oddjob

Does the water jacket empty completely (or adequately) thru the water pump? i.e. pulling the lower hose and thermostat empties the block?

Had to replace coolant at a track event this fall with water and want to make sure I don't have a freeze problem now that the cold weather is here.

Jfrahm

I use a wet vac. Works well.

V2Rocket

my experience, no it doesn't completely empty the block but gets most of the way there.
you'd probably have to have the back of the car lifted higher so the coolant flows downhill towards the WP.

StoogeMoe

When I prepare my race car (BMW E30) for the winter, I just empty the radiator, then fill it up with 100% antifreeze. Then run it up to temperature. It ends up being about 40% antifreeze mixture which gets me through the winter.

Then when it's time to hit the track, I completely drain everything and fill with water and wetter.

Oddjob

Sucking out of where - thru the water pump?

Swenny

From Clarks
There is a drain plug in the block also.

Oddjob

Only on early blocks.

Jfrahm

Coolant tank and lower radiator, radiator hose, both ways.

87944turbo

How early? There's one on my 87 turbo block.

Swenny

Mine is an '87 n/a

Oddjob

My bad, there is a drain plug. I looked for it previously and missed it under the exhaust manifold.

chudson

Oddjob

I drain the radiator and then remove the lower hose where it attaches to the radiator. Then, after insuring that the lower hose is clear of the power steering pulley, I start the engine and wait for the thermostat to start opening. As it opens, it allows the coolant to drain out of the block. As the flow starts to diminish, I shut the engine off so as to not allow the water pump to run dry and I then reinstall the lower hose once the flow becomes a dribble. Have done this countless times over the years both on my cars and all the similar designed cars that we service. Some may be uncomfortable with this method and if you are don't do it, but it works.

Cliff

Dan Martinic

That drain plug is on my '88 951 (I think it's an August '87 build).

FYI when I removed my head, I drained via front hoses etc. and there was plenty of water in the rear cylinder area and some in the bottom of the other three

KevinGross

The block drain (pictured) was removed for the 3 litre 944S2 blocks, because of changes to the cylinder location. AFAIK it remains for all other 944-series engines.