Cooling Fan Speed - Page 2

Dave6 · 4th October 2019, 18:51

Thanks Simon. That's really helpful. I have limited DIY skills so I probably wouldn't want to tackle it. I have a decent local garage so I will see if they can help. How did you go about your fix?

SD1too · 4th October 2019, 18:59

Quote:

Originally Posted by Dave6

I have a decent local garage so I will see if they can help. How did you go about your fix?

I renewed two motor brushes but I have to tell you that no garage will be able to do that.

I'd suggest that you send a PM to club member Arctic. He keeps a range of fan spares and may well be able to help you. Club trader Jules, at Colwyn Bay, may also be able to supply a replacement system that your garage can fit.

Simon

Dave6 · 4th October 2019, 19:06

Thanks Simon. I will pop down to the garage tomorrow and take it from there. They have used Rimmer Bros for a few other bits and pieces but it's probably more cost effective to get the fan from someone on here. Do you know if a new fan is a 'plug and play?'

SD1too · 4th October 2019, 19:15

Quote:

Originally Posted by Dave6

Do you know if a new fan is a 'plug and play?'

A new MGR fan using the resistor system can replace your 3 speed system without modification, but they are several hundred pounds. To put that into perspective, a set of new brushes is £20.

Jules will sell you an aftermarket system. Your garage will need to follow his instructions on how to wire it to your existing control box. That solution is cheaper but still expensive compared with new brushes.

Simon

COLVERT · 4th October 2019, 19:52

Dave. If you have a trawl through the How-To section on the forum you will find lots of posts, pictures and answers to do with the fan system.---

stocktake · 4th October 2019, 20:37

Quote:

Originally Posted by SD1too

Cycling speed applies only to resistor systems which you don't have. So you can forget about that.

Simon

Interesting, I have personal experience of a three speed fan cycling due to low speed only failing, it was on a members car close to me and I have to admit i was surprised but as I say I have seen it with my own eyes and can confirm 100% it can happen.

SD1too · 4th October 2019, 21:23

Quote:

Originally Posted by stocktake

Interesting, I have personal experience of a three speed fan cycling due to low speed only failing ...

We both know Dave that the only way this can happen is if the low speed supply brush fails. Then, when the trinary switch calls for medium speed it will run but only at low speed because there are only two brushes in service not three.

I think that what you witnessed was an extraordinary event. Did you dismantle the motor to find out what had actually happened?

Cheers,

Simon

stocktake · 5th October 2019, 06:36

It Was on Pab's motor Simon, never got the chance to strip it out and have a look. He wanted it replaced with the two speed version, It was an 04 car and you would have thought it would have been a two speed fan but it was certainly three speed four wire fan that appeared original.

It definitely cycled on and off I have never known another 3 speed fan do this, looking back it was certainly not a high speed.

So I believe your explanation is correct. I also believe that the trinary switch called, the remaining two brushes caused the motor to operate and successfully satisfied the trinarys needs and as such shut down until it reach its threshold again. Hence the cycling.

T-Cut · 5th October 2019, 12:38

Quote:

Originally Posted by stocktake

I also believe that the trinary switch called, the remaining two brushes caused the motor to operate and successfully satisfied the trinarys needs and as such shut down until it reach its threshold again. Hence the cycling.

I hadn't thought about it before, but isn't fan cycling logical for all motors?

Why would a faulty 3-speed fan run at a higher speed to cool the condenser but not trip off when the trinary pressure dropped? The implication is a faulty 3-speed would run continuously at higher speed while ever the aircon was in use.

TC

SD1too · 5th October 2019, 13:25

Quote:

Originally Posted by T-Cut

Why would a faulty 3-speed fan run at a higher speed to cool the condenser but not trip off when the trinary pressure dropped? The implication is a faulty 3-speed would run continuously at higher speed while ever the aircon was in use.

I don't think anyone is suggesting that particular scenario. What is the precise nature of the fan fault which you are considering?

Simon

5th October 2019, 06:36	#18
stocktake Vis Whiz Rover 75 2.5 auto Saloon Join Date: Jun 2007 Location: LEEDS Posts: 20,587 Thanks: 2,057 Thanked 3,056 Times in 1,621 Posts	It Was on Pab's motor Simon, never got the chance to strip it out and have a look. He wanted it replaced with the two speed version, It was an 04 car and you would have thought it would have been a two speed fan but it was certainly three speed four wire fan that appeared original. It definitely cycled on and off I have never known another 3 speed fan do this, looking back it was certainly not a high speed. So I believe your explanation is correct. I also believe that the trinary switch called, the remaining two brushes caused the motor to operate and successfully satisfied the trinarys needs and as such shut down until it reach its threshold again. Hence the cycling. __________________ Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident

4th October 2019, 18:51	#11
Dave6 Newbie 2002 V6 2.5 Join Date: Apr 2019 Location: North West England Posts: 21 Thanks: 3 Thanked 0 Times in 0 Posts	Thanks Simon. That's really helpful. I have limited DIY skills so I probably wouldn't want to tackle it. I have a decent local garage so I will see if they can help. How did you go about your fix?

4th October 2019, 19:06	#13
Dave6 Newbie 2002 V6 2.5 Join Date: Apr 2019 Location: North West England Posts: 21 Thanks: 3 Thanked 0 Times in 0 Posts	Thanks Simon. I will pop down to the garage tomorrow and take it from there. They have used Rimmer Bros for a few other bits and pieces but it's probably more cost effective to get the fan from someone on here. Do you know if a new fan is a 'plug and play?'

4th October 2019, 19:52	#15
COLVERT This is my second home R75 Saloon. Join Date: Feb 2009 Location: France/or Devon. Posts: 14,003 Thanks: 3,851 Thanked 2,167 Times in 1,816 Posts	Dave. If you have a trawl through the How-To section on the forum you will find lots of posts, pictures and answers to do with the fan system.---