Cooling fan help - Page 2

GreyGhost · 12th November 2007, 13:45

Quote:

Originally Posted by Steven D

PS Sorry - just wanted to clarify that the fan does not seem to come on during normal driving - only when the car is slowed to park or stopped to reverse, etc...

If I have this right, the fan should only operate at all if the vehicle is doing less than 30MPH. Otherwise airflow through the rad will cool it sufficiently.

T-Cut · 12th November 2007, 16:32

I also believe you are describing the normal behaviour of the 2-speed fan fitted to all 1.8/1.8T models. It's significant that you have only experienced the car's cooling system during the colder part of the year. When the weather warms up next year, you will probably experience other features, like its high speed operation.
It will be useful for you to know the type of system you've got. Does it have the slow speed resistor system? Knowing this will allow you to plan for any possible failure that may occur in the future.
You can gain a clearer picture of how the 2-speed system works by reading just the parts in the post http://www.the75andztclub.co.uk/foru...ead.php?t=1371 as it relates to the 1.8 engine. Forget all the other variations and try to get an understanding of the specific system you have.
As to the apparently strange way your fan works, remember that the A/C condenser, which is also cooled by the fan, is actually mounted just in front of the engine radiator, from which it can absorb some heat by radiation. The A/C condenser is like a radiator, but runs at much lower temperatures, so a bit of additional heat can have a big effect.
If you've not so far heard the high speed turbine-like fan, I don't think you have anything to worry about.

TC

Steven D · 14th November 2007, 10:29

Thankyou Gents,

That gives me great comfort. You are indeed correct, the fan only comes on when the car is either stationary or 'creeping' about, i.e. parking, reversing, etc.. and even then it's only rarely. I have not noticed the fan when driving above 30mph and I have listened for it intently !!.

I will read the 2-speed fan thread. I don't seem to have that resistor that has been mentioned at 2.00.

Again, my many thanks. I will keep it monitored closely.

Now all I need to do is sort the creaking passenger window and the rattle behind the dash which disappears with varying temperature. I may have to venture behind that glove box and check out the BCU. Problem is that I have the touch of an elephant and the ethos of "if it's not broken don't fix it" definitely applies to me....... I always end up thinking "why didn't you just leave it alone".

Again many thanks. This truly is a great place to be !.

T-Cut · 14th November 2007, 13:45

Quote:

Originally Posted by Steven D

I have not noticed the fan when driving above 30mph and I have listened for it intently !!

I don't think the fan has any road speed related control. It's all based on fluid temperatures or A/C pressure. The ram effect at 30mph just happens to provide enough cooling to prevent the thermal trip. In very hot weather, you'll probably have to drive faster to get the same effect.

TC

Steven D · 14th November 2007, 15:30

Yes, sorry - I didn't mean to intimate I'd taken your 30mph comment as meaning some kind of 'switch' !. I'm happy that it does not seem to have (yet ?) taken on the characteristics of some of the problematic ones I have read about within the threads. I do understand though that the 2-speed unit is less problematic. Funnily enough, this is the first car I've ever owned (at the tender age of 38), all my previous ones being company cars. It's become something of a obsession of a owning a car....... I'll get some photos up soon after I've finished Zymol-ing it to death. Beautiful car, though.

12th November 2007, 16:32	#12
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,754 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	I also believe you are describing the normal behaviour of the 2-speed fan fitted to all 1.8/1.8T models. It's significant that you have only experienced the car's cooling system during the colder part of the year. When the weather warms up next year, you will probably experience other features, like its high speed operation. It will be useful for you to know the type of system you've got. Does it have the slow speed resistor system? Knowing this will allow you to plan for any possible failure that may occur in the future. You can gain a clearer picture of how the 2-speed system works by reading just the parts in the post http://www.the75andztclub.co.uk/foru...ead.php?t=1371 as it relates to the 1.8 engine. Forget all the other variations and try to get an understanding of the specific system you have. As to the apparently strange way your fan works, remember that the A/C condenser, which is also cooled by the fan, is actually mounted just in front of the engine radiator, from which it can absorb some heat by radiation. The A/C condenser is like a radiator, but runs at much lower temperatures, so a bit of additional heat can have a big effect. If you've not so far heard the high speed turbine-like fan, I don't think you have anything to worry about. TC

14th November 2007, 10:29	#13
Steven D Newbie Rover 75 1.8T Join Date: Nov 2007 Location: Co. Durham Posts: 28 Thanks: 0 Thanked 0 Times in 0 Posts	Thankyou Gents, That gives me great comfort. You are indeed correct, the fan only comes on when the car is either stationary or 'creeping' about, i.e. parking, reversing, etc.. and even then it's only rarely. I have not noticed the fan when driving above 30mph and I have listened for it intently !!. I will read the 2-speed fan thread. I don't seem to have that resistor that has been mentioned at 2.00. Again, my many thanks. I will keep it monitored closely. Now all I need to do is sort the creaking passenger window and the rattle behind the dash which disappears with varying temperature. I may have to venture behind that glove box and check out the BCU. Problem is that I have the touch of an elephant and the ethos of "if it's not broken don't fix it" definitely applies to me....... I always end up thinking "why didn't you just leave it alone". Again many thanks. This truly is a great place to be !.

14th November 2007, 15:30	#15
Steven D Newbie Rover 75 1.8T Join Date: Nov 2007 Location: Co. Durham Posts: 28 Thanks: 0 Thanked 0 Times in 0 Posts	Yes, sorry - I didn't mean to intimate I'd taken your 30mph comment as meaning some kind of 'switch' !. I'm happy that it does not seem to have (yet ?) taken on the characteristics of some of the problematic ones I have read about within the threads. I do understand though that the 2-speed unit is less problematic. Funnily enough, this is the first car I've ever owned (at the tender age of 38), all my previous ones being company cars. It's become something of a obsession of a owning a car....... I'll get some photos up soon after I've finished Zymol-ing it to death. Beautiful car, though.