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MG MGB Technical - Possible MGB fan problem

Hi there again,

I would like to thank you all for your quick reactions on my gearbox question, they really helped me out.
My 78 MGB is equipped with two cooling fans. I thought that they were supposed to operate together, yet I have seen only one working (making a terrible noise by the way). Engine temperature stays ok though....even after long trips.
Does anyone know if something is wrong with the "not operating" fan on my "B", or is this normal?

Thanks,
Joost
Joost

They should operate together, I'm sure. You will have to check the wiring, connectors and the motor itself. In the UK only one fan was fitted except for V8s, so it's not surprising that you don't overheat. The fan(s) shouldn't come on while driving, only when in slow traffic. Above about 30 kph there is plenty of air passing through the rad without the fans.
Mike
Mike Howlett

Had an LE with fan problems.

Replaced or cleaned all electric connections after taking the motors apart for a good cleaning.

There were no covers on the armature shafts, so a lot of dirt and grim worked its way in around the brushes.

They are just a typical DC motors, so they aren't all that complicated. Take a look where the shaft comes out of the housing.

Something else to try first -- disconnect the motor wires, then bring power by jumper wires to see if really works.

Probably just a bad connection that's keeping it still.
glg

If you do disassemble the fans, pay attention to the little index mark on the body.

Mike
Mike Phillips

Definitely should operate together. You should find a two-pin connector connecting each fan to the loom, but these are just behind the grill and prone to corrosion. Pull these apart and make sure they are clean and the pins and sockets haven't been partially pushed out the back of the housing, then reassemble with Vaseline. With the ignition on and the thermo switch connections linked the fans should run. If the 2nd fan doesn't now run push the probes of a voltmeter in the back of the motor half of the connector and see if you have 12v. If you don't (left-hand motor not running?) then you have a wiring problem back towards the other motor. If you do then either a wire to the motor is broken inside the insulation or the motor itself is faulty. Could be a sticking brush, but if you can't fix it and have to get a new one you may have to get a new fan blade too, they are a pig to get off the old shaft. If installing a new motor make sure it spins the right way and blows through the rad and doesn't suck, and make sure the blades are on the spindle the right way - the thick edge should lead and the thin edge trail, just like an aircraft wing.
Paul Hunt

The fans on my '77 were noisy, slow and just worn out. I replaced them with one large 14 " replacement from Checker Auto. The cost is about $130.00. It mounts right on the radiator, with the plastic anchors. I still use the original sensors and switch. And does it Cool! And it's quiet. I am running with a 180 degree themostat, even in 80+ degree weather.
Yes, you can improve your MG!
I would use this fan on any car, including those that have a belt driven fan. They improve performance, fuel mileage and power. Makes the car quieter, and I never have to worry about overheating any more.
Safety [cool] Fast
Dwight
Dwight McCullough

Hmmm, I have heard of more than one case of the ties that go through the rad core chafing through the tubes.
Paul Hunt

This thread was discussed between 22/07/2003 and 25/07/2003

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