MGB Register Forum

My car is/was fitted with a 4 blade metal fan on the water pump pulley.
I parked the car up on Sunday night.
Intended to go shopping monday morning, Started the car- fine. I'd done about a quarter of a mile and the whole car started a mega vibration. Gingerley turned back and returned home.
The metal fan had thrown a blade, which miraculously hadn't hit or damaged anything, so I removed it relying on the electric fan.
Later, I noticed that there was more than the usual cacophony from the engine. Subsequent investigation found that water pump was knackered.
So Half a mile of motoring with the now 3 bladed fan had done for the pump!
Thinking about it I was lucky to get away with no damage.

Do you really need a mechanical and electric fan?

Hi Vic. The mechanical fan was on when I got the car 5 years ago, so I left it on.
I don't trust electric fans anyway, so belt and braces.
To be honest, I don't think the mechanical fan did much anyway.
I've always thought that the 1978 cooling system is marginal, in that any traffic stoppages soon send the temp gauge soaring, but so far the electric fan has always worked. It's been like that for 5 years/10,000 miles though.

Mine is overheating badly but it's likely to be a cracked cylinder head which will be removed soon otherwise I've not experienced any overheating. I suppose the answer would be to fit a second electric fan as per the V8.

You are lucky. I have heard of a metal fan blade slicing a neat slot in the bonnet. 50 year old metal can be prone to metal fatigue, as you now know.

I can't check my metal fan at the present time, but are the blades rivetted on? I did wonder if it was the rivets which had failed or a failure of the metal blade itself?
If rivetted, I guess failure of the blade around the rivet holes is most likely?

Ian F

I'll take a pic today.

My 3 bladed fan is riveted-

Here's a pic of the broken fan.
I hadn't noticed before, but it appears to have been messed about with.
It#s 3 bladed not 4 bladed.

Looks like you have some additional holes drilled there, wonder if that has weakened the fan blades resulting in the eventual shearing?.