Which radiator fan?

[syncropatrick]

Hi,
My 2.1 petrol DJ has radiator fan 251 959 455 M. Larger diameter motor. Has two post terminals on rear for power. I'm not sure if this is the correct one.
I have acquired another fan which is 251 959 455 A. Smaller diameter motor. Has a flying lead with a round connector for power. Not sure if this is the correct one.
Can anyone advise which is the correct fan to use?

My current fan is louder than normal at both speeds and drawing ~55A at slow speed, so needs attention. It draws air well but I noticed the radiator is not in best nick with broken and flattened fins. I've run warm water over the vanes for 20 mins and got out a lot of mud (its a syncro so has seen plenty of muddy wading fun). Might a radiator which is blocked be causing the fan to work harder to pull air through? (not talking about internal flushing or blocking). Not convinced by this line of thought as the rest of the cooling system seems to be working well.

[AdrianC]

Might a radiator which is blocked be causing the fan to work harder to pull air through?

It'll cause it to work more often, since it won't cool as effectively, but the fan isn't hermetically sealed to the rad, so it won't make much difference to the fan itself. The airflow will just be much less effective, since more'll bounce off the clagged surface of the rad, meaning the fan'll still have to work longer and more often to cool the coolant down.

Quick and easy test while you've got the fan off - fire it up with nothing in the way, then sit it on a solid surface, and see if there's more current being drawn. I bet there won't be.

[syncropatrick]

Thats good advice, thanks.
I tried to remove the fan yesterday, without removing the radiator. It looked possible to get at the 6 bolts holding the cowl onto the rad by removing both front grills, but the bolts were well rusted and I was worried about breaking one so didnt proceed. The fan motor had various openings and I squirted grease inside and smeared some over the front where the hub circlip is. Fan didnt get any quieter so guess the problem is further inside.

Any ideas on what fan to replace with?