Problem.
Just resting in bed one morning, engine running. Suddenly it started making a crunching noise. Sounded ominous.
Ran out and immediately turned the engine off.
This happened twice or three times. A loud metallic crunching sound.
Next day when I started it up, it began overheating quite badly.
Overheating
Most of the coolant ended up squirted all over the engine compartment floor.
When I started the engine, after about an hour, it started ‘boiling out’. The coolant was just boiling off the top of the cylinder heads and being forced out.
This can point to a badly bled system, or a more serious problem with your cooling system.
BMC 1,800 marine waterpump
After talking to a couple of people, I was fairly convinced that the problem was with the waterpump.

Symptoms including:-
- Metalic crunching sound; the pump scraping on it’s housing.
- Overheating.
- No oil in water or water in oil: Not being a problem with the head gasket.
Procedure for removing waterpump
The waterpump resides behind the engine. The fan belt rotates around it, along with the alternator and the drive-shaft.
- Loosen screws on waterpump wheel: There are four nuts that need to be loosened.
- Loosen alternator: Slacken the belt off.
- Remove waterpump wheel: Fully take nuts out and gently lever the wheel from the waterpump. Keep this, you will need it later!
- Remove water from your system: Pick the place where the cooling system piping is at it’s lowest. Remove the pipe here and bleed the coolant out.
- Remove pipes: There’s a pipe which connects the waterpump to the cooling jacket. Carefully remove this.
- Remove waterpump: There are 4 nuts and washers holding it on. Slacken these off and remove the pump.
You should be left holding your old and broken waterpump in your hand.
You may want to dispose of this in the best way you see fit. Continue reading “BMC 1800 waterpump”

