Strange fan motor but Siemens

[vitesse]

Nice hot day at 28c, shortly after start heard a noise from the front and knew somehow that it was the fan blades parting company. The fan was replaced before I bought the car last December.

Surprised indeed by what I found when I removed the bumper, blades marked Siemens, peeled back the unusual white sticker which just reveals a round hole.

Any idea of how to permanently reattach it to the spindle, I doubt if it could be drilled and threaded. I do have a dead commutator damaged fan with the correct mounting on the spindle, but has anyone tried to remove the mounting, succeeded?



Regards

[T-Cut]

It looks similar to an MGR fan motor, but it's not. The field windings of the original motors are not exposed as shown here and it has has a mounting flange permanently attached to the spindle. This fan unit would seem to have a different blades attachment system, though it's unclear what. The OEM fan unit is attached to the flange by three 'bayonet' clips in the central boss area. There appears to be nothing like that here. It surely can't be a simple push fit into the spindle?

Can you post a closeup photo of the rear fan centre?


EDIT:
Here's a photo that shows a side view of the flange.


TC

[vitesse]

Thanks for the reply, strangely it resembles the original but isn't and the blades are just a snug push fit on the spindle. No locking mechanism.

Sorry, no picture of the rear at the moment as it's still mounted.

I tried to remove the old three bayonet clips (as many have tried) using heat first but only managed to break one of the clips.

Regards

[T-Cut]

Was it performing satisfactorily before the fan came off? Looking at the size of the spindle, I'm a bit sceptical it has anything like the power/displacement rate of an OEM system. Is the fan the same size and shape as usual? Is there any indication of power/wattage on the motor?

As to refitting the blades, I fear once this push-on type fitting has separated, it will continue to separate. I guess you could try bonding it on with a film of superglue. The problem is, it's an interference fit, so no place for an adhesive to go.

TC

[vitesse]

Yes, it worked well at least in the six months I’ve had the car, the running temperature is a constant low 90s and the AC in continual use. I tested the fan several times when I bought the car as the car was seriously overheating (airlock) https://the75andztclub.co.uk/forum/s....php?p=2690481

Superglue is exactly what I’ve used as a temporary measure until I can get a replacement.

Fan looks like the original and the mountings are identical but I’ve not seen any marking on the casing, the spindle diameter doesn’t seem all that different either but now the superglue is in place I can’t measure it. Perhaps later when the replacement arrives, if I get the glued blades off!

I might ask the supplying garage where they got the fan unless someone comes along and identifies the fan motor, otherwise it might remain a mystery, thanks for your input.

Regards

[T-Cut]

It seems that Siemens have simplified the fan attachment. A pressed-on fit using a metal ferrule (I think from your photo) makes it simpler/cheaper, functional but not replaceable. So, you have to buy a new fan/motor assembly rather than just the fan unit. It's logical I guess since 99% of the problems are with the motor.

In that context, I notice the low speed resistor is the original 50-75 watt type. You should consider upgrading that to the recommended 'Gold' 100 watt version. The one you have will fail sooner or later. You can get one from electronics outlets like Farnell, from forum traders and from eBay.

TC

[vitesse]

Thanks for the resistor reminder, I have a gold one lying around somewhere but the silver one will have to do until the replacement fan arrives in a few weeks.

I messaged Nick at ECP2004 about his fans as his ebay ones https://www.ebay.co.uk/itm/ROVER-75-...0AAOSwfVpYpx0I look similar to the one fitted, same Siemens marking, same white sticker but he’s never seen the press fit spindle ones. He also said that while Siemens were the original suppliers, MG Rover later used a company called Brose.

After the blades separating and the non-repairable mounting I would avoid these types and recommend the original flange. I’ve had the original blades on / off on several cars and never had a problem re-attaching them. This cost saving measure doesn’t do us home mechanics any favours.

Regards

[Arctic]

Hi Mike
Can you take a photo further back so we can see the whole cowling on the car, that fan motor looks like it as been put on back to front, even though we know it hasn't, is there not a circlip holding the fan blades onto the spindle ?

[vitesse]

Originally Posted by Arctic

Hi Mike
Can you take a photo further back so we can see the whole cowling on the car, that fan motor looks like it as been put on back to front, even though we know it hasn't, is there not a circlip holding the fan blades onto the spindle ?

Steve, will take a photo when I return to the garage after lunch.

Sadly no circlip, no groove on the spindle or perhaps not that I've seen anyway.

Update from helpful Nick at ECP2004, the ones he sells https://www.ebay.co.uk/itm/ROVER-75-...9b1a%7Ciid%3A1 are the push fit type and says he’s sold over 200 without problems, unlike the originals.

He has genuine fan motors with the three legged bayonet mounting but at £389 I’ll make do with either the superglued one, or an old 3 speed from a donor which I re-brushed six years ago and will check before fitting.

Shame that Siemens never machined a thread into the spindle for a bolt ensuring 100% security for these push fit types but I guess that’s the way of the modern world.

Mike

[slovcan]

Originally Posted by vitesse

Steve, will take a photo when I return to the garage after lunch.

Sadly no circlip, no groove on the spindle or perhaps not that I've seen anyway.

Update from helpful Nick at ECP2004, the ones he sells https://www.ebay.co.uk/itm/ROVER-75-...9b1a%7Ciid%3A1 are the push fit type and says he’s sold over 200 without problems, unlike the originals.

He has genuine fan motors with the three legged bayonet mounting but at £389 I’ll make do with either the superglued one, or an old 3 speed from a donor which I re-brushed six years ago and will check before fitting.

Shame that Siemens never machined a thread into the spindle for a bolt ensuring 100% security for these push fit types but I guess that’s the way of the modern world.

Mike

Couldn't you press the fan blade back on, mark the shaft just in front of the fan, drill a small hole through the shaft and put in a roll pin to stop the fan coming off again?