V6 dumps coolant at MOT - Page 3

Organiser · 15th May 2015, 19:43

Two pictures below first one of a 3 speed fan without a resistor, second of a 2 speed with a resistor.

Tom.

Salad-Dodger · 15th May 2015, 19:59

Already done the de mist test as mentioned earlier. The fan comes on like its going to take off and stays on. I've also started the engine from cold and looked to see what the fan does when it comes on. It doesn't come on until the engine is hot and when it does, its loud and fast. Also noticed that the clutch on the air-con compressor doesn't engage but that's for another day.

I've had a look on ebay just to have a look at what the brush plate looks like and I think I could fit the brushes if I can find some. The gold resistor is another thing though. I would need to know where it would be wired in and why.
Putting my Sister in a cab or on a train to London just is not an option for reasons I cannot go into on here!

I've just heard a mail come in and I've had a look at the excellent pics from "organiser" and I definately don't have a resistor of any kind, so it looks like I have a three speed fan motor. I'll count the wires in the morning to confirm the motor type.
Bad luck really as it behaved itself until the MOT. Steve

ProfDave · 15th May 2015, 20:08

If there is no resistor then a gold one is not going to help. Still suggest getting some o rings; if you do test things and the fan is suspect I had a great kit from Jules for the ZTT which had a three speed fan and it replaced the original fan with a better quality one. Quite easy to fit to and lots of good instructions. But as said be sure this is it first !!!!!!!!!!!!

COLVERT · 15th May 2015, 20:30

Your brushes probably look like this------------

Salad-Dodger · 15th May 2015, 20:47

Like I said, I've no idea about the resistor or what its used for (yet) as nobody has explained the different models. I'm quite versed in mending motorcars but I need all the information first to effect a repair.
Assuming then, I have a three speed version of the motor, I will need to know the size of the brush as I may have some brushes here that I can use. I've mended many other motors by filling the brushes to a size and soldering them in.
I think that tomorrow will be taking that bumper off to find out what I have. Its pretty clear that I only have the one speed. There must be a control unit somewhere that feeds the motor with the correct voltage to control the speeds. Putting a meter over the wires may tell a tail.

Thanks for that pic Colvert. That's a much better pic than the ones on ebay. Just need the size of those brushes now. Steve

SD1too · 15th May 2015, 21:32

Quote:

Originally Posted by Salad-Dodger

Already done the de mist test as mentioned earlier. The fan comes on like its going to take off and stays on.

Steve, I'm sorry to say that I'm confused by your evidence. The demist test will trigger the slow speed and if that is working then your engine would not reach 115° with no fan running as you reported earlier.

Quote:

The gold resistor is another thing though. I would need to know where it would be wired in and why.

The resistor is relevant only to the 2 speed motor. You say that you cannot see a resistor, so it's irrelevant.

Quote:

I'll count the wires in the morning to confirm the motor type.

That will be very useful; thanks Steve.

Quote:

Originally Posted by Salad-Dodger

I've no idea about the resistor or what its used for (yet) as nobody has explained the different models.

2 speed systems use the resistor in series with the motor to effect the slow speed. The resistor is shorted out when the motor is required to run at full speed.

Quote:

I think that tomorrow will be taking that bumper off to find out what I have.

Yes please!

Quote:

There must be a control unit somewhere that feeds the motor with the correct voltage to control the speeds.

The control box is mounted on the fan shroud. You will see it when you take off the bumper and swing back the shroud. The way the control box works depends upon whether you have a 2 speed 2 wire or a 3 speed 4 wire motor. The latter doesn't achieve speed control by voltage.
If it turns out that you do have a 3 speed motor, I can tell you where to buy reliable replacement brushes. But let's wait to find out what you've got.

Simon

Salad-Dodger · 15th May 2015, 22:04

Well I think I have four wires as I can see three of them. When I find the plug I'll get the meter out. Its only a motor. Valeo make most of them and by an large, they all use the same components. Theres probably a part number on it somewhere for ID. Wont be that complicated.
If its open circuit then the brushes will come out for new ones but I'll need to know where they come from. If its ok, then it may be a control unit. You never know, I may be able to go there in my F and collect the parts.
I've got to look into this as I've a feeling it may have been tampered with. After all, why is the fan running at such a fast speed? That's never a slow speed. Almost takes off! Plus, there's a few other things I've not done yet like re-bleeding and changing the O rings.

Salad-Dodger · 16th May 2015, 08:53

I can confirm that it has a resistor. A really dirty one greyish in colour.
The other wires I can see were some rubbish left by the previous owner. Probably lighting as I did find a couple of weeks ago a starter gadget thingy mounted on one side of the bumper, or maybe horns or something.
Anyway, I don't know if this changes anything, I'll have a read through this thread later when I've looked at the bleeding issue and the O rings. Steve

Salad-Dodger · 16th May 2015, 10:13

Followed the fill procedure but no coolant coming from the pipe on the neck.
As soon as it starts, coolant rises in the neck.
When it gets to 90 degrees, still no fan and coolant coming past the cap. Tried changing the O rings but no luck. Both pipes on rad are hot.
Fan will run on d-mist though and no cream in the oil fill neck. Steve

kaiser · 16th May 2015, 10:27

How much was it filled when cold?

15th May 2015, 19:59	#22
Salad-Dodger Gets stuck in MG ZT-T 190 Join Date: Feb 2015 Location: Chatham Posts: 592 Thanks: 34 Thanked 66 Times in 62 Posts	Already done the de mist test as mentioned earlier. The fan comes on like its going to take off and stays on. I've also started the engine from cold and looked to see what the fan does when it comes on. It doesn't come on until the engine is hot and when it does, its loud and fast. Also noticed that the clutch on the air-con compressor doesn't engage but that's for another day. I've had a look on ebay just to have a look at what the brush plate looks like and I think I could fit the brushes if I can find some. The gold resistor is another thing though. I would need to know where it would be wired in and why. Putting my Sister in a cab or on a train to London just is not an option for reasons I cannot go into on here! I've just heard a mail come in and I've had a look at the excellent pics from "organiser" and I definately don't have a resistor of any kind, so it looks like I have a three speed fan motor. I'll count the wires in the morning to confirm the motor type. Bad luck really as it behaved itself until the MOT. Steve

15th May 2015, 20:08	#23
ProfDave This is my second home ZTT, Contemp Saloon, Duotone Tourer Join Date: May 2012 Location: Llandeilo Posts: 4,192 Thanks: 290 Thanked 387 Times in 333 Posts	If there is no resistor then a gold one is not going to help. Still suggest getting some o rings; if you do test things and the fan is suspect I had a great kit from Jules for the ZTT which had a three speed fan and it replaced the original fan with a better quality one. Quite easy to fit to and lots of good instructions. But as said be sure this is it first !!!!!!!!!!!!

15th May 2015, 20:30	#24
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	Your brushes probably look like this------------

15th May 2015, 20:47	#25
Salad-Dodger Gets stuck in MG ZT-T 190 Join Date: Feb 2015 Location: Chatham Posts: 592 Thanks: 34 Thanked 66 Times in 62 Posts	Like I said, I've no idea about the resistor or what its used for (yet) as nobody has explained the different models. I'm quite versed in mending motorcars but I need all the information first to effect a repair. Assuming then, I have a three speed version of the motor, I will need to know the size of the brush as I may have some brushes here that I can use. I've mended many other motors by filling the brushes to a size and soldering them in. I think that tomorrow will be taking that bumper off to find out what I have. Its pretty clear that I only have the one speed. There must be a control unit somewhere that feeds the motor with the correct voltage to control the speeds. Putting a meter over the wires may tell a tail. Thanks for that pic Colvert. That's a much better pic than the ones on ebay. Just need the size of those brushes now. Steve

15th May 2015, 22:04	#27
Salad-Dodger Gets stuck in MG ZT-T 190 Join Date: Feb 2015 Location: Chatham Posts: 592 Thanks: 34 Thanked 66 Times in 62 Posts	Well I think I have four wires as I can see three of them. When I find the plug I'll get the meter out. Its only a motor. Valeo make most of them and by an large, they all use the same components. Theres probably a part number on it somewhere for ID. Wont be that complicated. If its open circuit then the brushes will come out for new ones but I'll need to know where they come from. If its ok, then it may be a control unit. You never know, I may be able to go there in my F and collect the parts. I've got to look into this as I've a feeling it may have been tampered with. After all, why is the fan running at such a fast speed? That's never a slow speed. Almost takes off! Plus, there's a few other things I've not done yet like re-bleeding and changing the O rings.

16th May 2015, 08:53	#28
Salad-Dodger Gets stuck in MG ZT-T 190 Join Date: Feb 2015 Location: Chatham Posts: 592 Thanks: 34 Thanked 66 Times in 62 Posts	I can confirm that it has a resistor. A really dirty one greyish in colour. The other wires I can see were some rubbish left by the previous owner. Probably lighting as I did find a couple of weeks ago a starter gadget thingy mounted on one side of the bumper, or maybe horns or something. Anyway, I don't know if this changes anything, I'll have a read through this thread later when I've looked at the bleeding issue and the O rings. Steve

16th May 2015, 10:13	#29
Salad-Dodger Gets stuck in MG ZT-T 190 Join Date: Feb 2015 Location: Chatham Posts: 592 Thanks: 34 Thanked 66 Times in 62 Posts	Followed the fill procedure but no coolant coming from the pipe on the neck. As soon as it starts, coolant rises in the neck. When it gets to 90 degrees, still no fan and coolant coming past the cap. Tried changing the O rings but no luck. Both pipes on rad are hot. Fan will run on d-mist though and no cream in the oil fill neck. Steve

16th May 2015, 10:27	#30
kaiser This is my second home 75 Tourer 2.5 Auto, 1.8T, 75V8ZT Join Date: Jun 2007 Location: Johannesburg ZA Posts: 6,200 Thanks: 1 Thanked 859 Times in 613 Posts	How much was it filled when cold?