coolant change
Moderator: martauto
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march109
- Engaged to the E30 Zone

- Posts: 6632
- Joined: Sun Aug 20, 2006 11:00 pm
- Location: Bournemouth
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There are 11 in an M20B25.
Did you remove the block drain plug? flushed the rad through? and removed bottom hose to the rad?
Did you remove the block drain plug? flushed the rad through? and removed bottom hose to the rad?
325i Tech 1 Touring, breaking.
2.5 high comp. M20, 3.64 LSD, Fully undersealed, Spax springs & Bilstein shocks, s/s exhaust, Alpina rep wheels and more.
2.5 high comp. M20, 3.64 LSD, Fully undersealed, Spax springs & Bilstein shocks, s/s exhaust, Alpina rep wheels and more.
Ok, on the block near the back cylinder on the exhaust side you will find the block drain plug, will need a old washing up bowl or somthing because the other 8 liters will come out of there, farely quickly at first.
- Brianmoooore
- E30 Zone Team Member

- Posts: 49358
- Joined: Mon Jan 10, 2005 11:00 pm
The block drain has a 19mm hex head, is hidden under the exhaust manifold, and requires a ring spanner with a straight end, not angled like most combination spanners. The skin on your knuckles will not survive!
A cheating way to change the coolant is to drain the rad as you have, then use a hose to thoroughly flush all the old coolant out of the block, replacing it with plain water.
Reconnect all the hoses, etc., and fill with four litres of neat, undiluted coolant (for a 33% mix), then top up with plain water.
If you do drain the block, read up on the real possibilities of air locks, overheating, and possible cracked heads.
A cheating way to change the coolant is to drain the rad as you have, then use a hose to thoroughly flush all the old coolant out of the block, replacing it with plain water.
Reconnect all the hoses, etc., and fill with four litres of neat, undiluted coolant (for a 33% mix), then top up with plain water.
If you do drain the block, read up on the real possibilities of air locks, overheating, and possible cracked heads.
- Bobbydoughnut
- E30 Zone Newbie

- Posts: 73
- Joined: Thu Mar 03, 2005 11:00 pm
- Location: Glasgow
If you want to maximise life, remember to get the right coolant for it, if it's an M20, due to the mixed metal engine it could do with certain anti corrosion additives etc.

Aint white nice these days


