75ZT Community

I thought i would started this thread for our cooling fans we have on our cars,and try to keep this thread only about cooling fan issues we may have, this can be from a none working fan to a fan that is not cooling the engine as it should but is working.

I think you get the drift hopefully then we can build up and log of how faults were rectified and by what method (ie) modification or a complete new system.

As we know our R75 & MG ZT have three kinds of fans two version of the petrol fan and a diesel fan these could be the three speed four wire fan, the two speed three wire fan, and the two speed with two wires incorporting a silver resistor.

Then there are different tests we can undertake to see if our fan is working or to find out which fan we have.

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How to determine which fan your cars as and if is working on low speed, you will have one of two fan a three speed fan or a two speed, the three speed fan will have no resistor the two speed will have a silverresistor in place unless it as been changed for an up rated Gold resistor Arctic.

To check you need to look through the front grill at about 2.0 oclock between the fan blades, if the fab blades are are in the way you can use a long screwdriver to push the fan blade round until you reach a gap at the place above, under no curcumstance do this with the engine running.

If you have a three speed fan with no resistor you will see only the two lugs where it be Fig 1
1

If you see a silver resistor in the same place then you have a two speed fan Fig 2
2

If you see a Gold resistor that means you have a two speed which as been up rated from the silver one Fig 3
3

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How to test if the fan is working on low speed weather it is a three speed fan or a two speed fan, is to do the demist test as below, to do this test make sure from the start that the A/C is in the turned off postion.

If you have a diesel car you only need to put the key in the ignition and set it to postion II you do not have to start the engine unless you prefer to here we go.


With key at postion II in the ignition press the demist button on the A/C control Fig 1
1

Once the demist button as been pressed the A/C control will illuminate and show your settings press this either to low or 16 Fig 2
2

Now you need to look through the front grill and see if the fan is running continuous without interuptions or pulsing on and off if it runs continually then the low speed is working.Fig 3
3

If not the low speed as failed and if your fan is a three speed with no resistor then more than likely the medium speed will not be working either, if you have a fan with a silver resistor the resistor as failed and will need chaning to a Gold one.

The same test is carried out on the petrol engines but this time the engine must be running to do the demist test above.
Arctic.

Hi Steve

I think what would be useful is a flow chart for checking out the fans - sort of an idiots guide, not that I'm suggesting you or anyone else are idiots of course , only I think it may help newbies in identifying fan problems and then the solutions?

I have somewhere a drafty version of one I was playing with earlier if I can find it I'll ping it to you and see what you think. I've also thought about either a short video or sound recording of the sound of a healthy (2-speed) fan when being tested? It good also go in the on-line magazine on the Enthuse site perhaps?

Gary M

Hi Gary.
Anything related to the R75 and MG ZT fans would be good for this thread more info the better,i have taken lots of photo's today of differnt fans i have from the diesel to the 1.8T two speed and three speed hopefully will be posting some later just trying to get them in some order by the end of the week this thread with members imput also it should more or less help t find what maybe wrong with the fan and how to solve it Arctic

Good idea for a thread Steve, i can produce a flow chart for you if you want , we could sort it next time we get together if you wish

Trebor wrote:Good idea for a thread Steve, i can produce a flow chart for you if you want , we could sort it next time we get together if you wish

Hi Rob.
That would be great and i will take you up on that kind offer cheers Arctic.

Hi guys do not forget to test your fans now the warmer weather is on it's way I have had a few members reporting that their fans are not working on the low speed after winter. Arctic