coolant fan problem

[keitht]

Car is a 52 plate zt 2.4 auto, when ignition is switched off coolant fan contiues to run, only way to stop appears to be disconnecting battery, car doesnt appear to be overheating anybody help thanks keitht

[rich17865]

Have you checked the plenum? Is it full of water? This has to be the first point of call.

[IanDCW]

I had same problem, turned out to be relay problem. I stopped the fan running by removing the fuse for the fan. Meant I didn't have to disconnect battery, and I could get it to the garage.
Maybe others have suggestions too :)

Just found link to my problem

http://www.the75andztclub.co.uk/forum/showthread.php?t=88661&highlight=fuse+cooling+fan

[SD1too]

car doesnt appear to be overheating
Keith,

It might be if you have the usual fan motor problems. Start the car from cold, press 'demist' and tell us if the fan is running by listening at the radiator grille.

Simon.

[keitht]

Have you checked the plenum? Is it full of water? This has to be the first point of call.
Thanks for advice , but where is the plenum do you mean the heaer tank. incientally Ibought the car in Nantwich an lived in the area for over twenty years car an owner now in SW France

[keitht]

I had same problem, turned out to be relay problem. I stopped the fan running by removing the fuse for the fan. Meant I didn't have to disconnect battery, and I could get it to the garage.
Maybe others have suggestions too :)

Just found link to my problem

http://www.the75andztclub.co.uk/forum/showthread.php?t=88661&highlight=fuse+cooling+fan
I would certainly be a lot easier to remove a fuse as this would allow me to use the car whilst I sort the problem, not easy in SW France but which fuse is it thanks Keitht

[stocktake]

The V6 needs it's fan, not a good idea to disconnect it, it sounds like a stuck relay, more common than you may think :). Its a bumper off job to get to them.

Follow the advice SD1too and he will guide you to the solution. it is better to follow a procedure from start to finish with one knowledgeable member in these cases so i will leave you in the hands of SD1too ;)

[rich17865]

Thanks for advice , but where is the plenum do you mean the heaer tank. incientally Ibought the car in Nantwich an lived in the area for over twenty years car an owner now in SW France

Use the search tool and search for 'clearing plenum' a wealth of information to be found.

Nantwich a lovely place, Crewe not so :rolleyes: :D

[SD1too]

... but where is the plenum do you mean the heaer tank ...
Keith, you sound confused so here's a more detailed explanation.

The 'plenum' is the area between the engine compartment and cabin bulkhead. It's home to the car's main electronic control module (ECM) amongst other things. The plenum lies beneath the cover surrounding the windscreen wiper arms and is susceptible to flooding by rainwater when the drain tubes become blocked with leaves and other debris. When this happens the ECM gets wet and the result is very illogical and random electrical faults affecting several types of equipment.

You have reported only that your engine cooling fan is running unexpectedly. You've said that the engine doesn't appear to be overheating. Are you depending upon the car's temperature gauge for this conclusion? If so, I'm afraid that's a mistake with the 75/ZT. Your engine could be overheating because the lower fan speed(s) have failed and you won't be aware of it by looking at the gauge. Fan failure is a common problem with our cars. Note that if the temperature exceeds a certain value the fan is designed to run after the engine has been stopped and the ignition turned off. So your car might be behaving perfectly normally, and warning you that you need to take some action. The first test that you need to perform is described in my first post. The result will tell us whether to look at the fan system or to suspect a flooded plenum.

I'd also like to endorse what Stocktake says. You must not disconnect your fan otherwise you will risk serious overheating and much greater problems than you have at the moment.

Let us have the result of the 'demist' test please Keith and we'll proceed from there.

Simon.

[keitht]

Hi Simon, tryed the demist test this was result, reconnected battery car stone cold first thing in the morning, started car and swiched on demist fan still running. car neeed fuel took it for probably about 8 miles stopped for petrol switched off ignition fan had stopped, restarted car drove home fan still not running after ignition switched off tempgauge normal througout any comments appreciated Thanks Keitht

[COLVERT]

Still slightly confused. :confused:

When you switched on 'demist' which fan started running. ( Both. ? )

It should be the rad fan cos 'demist' puts on the aircon and also the rad fan.

The internal heater fan should go on to 'flat out' too.





Colvert. :D:D

[SD1too]

Yes, Keith, can you confirm that you're talking about the engine radiator fan? Thanks.

Simon.

[keitht]

Hi Simon Both Fans Running when emist engaged, went to the front of car to listen and confirm rad fan, but definitely not running when I stoppe for fuel. Any comments appreciate ,thanks Keitht

[SD1too]

O.K., so when starting the engine from cold with 'demist' pressed, the radiator fan runs. That's what it's supposed to do. However it's strange that, at the petrol station, it had stopped. At that time, was the air con. still in 'demist', or had you changed to 'auto' or 'econ' mode?

Second question: with a cold engine, please can you remove the expansion tank cap to check the coolant level. It should be about one third of the way up the tank.

Simon.

[COLVERT]

Hi Simon. Both Fans Running when demist engaged. Went to the front of car to listen and confirm rad fan running. But definitely not running when I stopped for fuel. Any comments appreciated ,thanks Keitht

When you stopped for fuel you would have turned the ignition off. This will turn the fan off too unless the engine is VERY hot when it might run for a few seconds before switching itself off.




Colvert. :D

[keitht]

Hi Simon yes i ha switshed to auto after a few miles, willcheck cooant level this morning . thanks for helping much appreciated , cheers keitht

[keitht]

Hi Simon Checked coolant level with egine cold and running it was as you said it should be, done about another 60 miles since without problem, coukd the relay have free'ed itself. all comments helpgreatly appreciated thanks keitht.

[SD1too]

Hmmm. All I can suggest now is that you monitor a digital display of the coolant temperature in your instrument pack (the gauge is useless). The guide on how to do this is in the forum's "How to..." section. The hottest it should get is one or two degrees above 100; the temperature at which the fan's slowest speed triggers.

Let us know if you have any further problems.

Simon.