850r overheating at standstill.

[steveyruss]

Hi guys. I'm new here. I'm having some problems with my 850r. It seems to be overheating slowly when on idle. It's absolutely fine at speed. This problem occurs around town at a standstill. It looks like the fan isn't working or isn't kicking in like it should. Is this a common problem and what steps should I take to diagnose it? Will I need a replacement fan and where can I get the parts? Thanks in advance.

[stribo]

It may be the temperature switch, or a relay. Easiest way to test the fan is to unplug it, and run 12Vs directly to it.

[MoleT-5R]

I'd have my money on a broken/corroded wire to the relays on the top drivers side of the fan/rad unit, give them a wiggle when it's hot and see if the fan starts

[steveyruss]

Thanks for the advice guys. I'm wiggling the wiring around and it around seems to have no affect. I'm having a friend come around on Monday to help me out more. When the engine is getting very hot on idle there seems to be small amount of smoke coming from the dipstick when I take it out. Is this normal or could it indicate headgasket problems too? I can't see any coolant/oil leaks thankfully.
.

[ajc106]

the smoke from the dipstick is the pvc system needs to be replaced

[Saaamon]

If it really is just a little bit of smoke i'd just leave it and keep an eye on it but its unrelated to the fan not working.

[merc85]

It will be the fuseable link off the starter motor, The Fan relay wont have a perminant 12v supply so wen the temp sensor tells the ecu to put the fan on it wont be able to power up.

Take a Direct 12v supply off the battery and wired it to the 12v on the fan relay. Should work then.

[steveyruss]

Looks like the fan is the least of my worries unfortunately! After giving the 850r a good run at speed the coolant tank is also making hissing noise once its cap is removed from the release of pressure. The coolant level is also noticeably dropping from time to time. Classic head gasket failure symptom methinks . The car was starting to overheat when I noticed the fan was not working but I didn't think that it was severe enough to cause damage like this. I'll have to book it into the local garage on Monday for a sniff test and then consider the options.

[craigoodwood]

ah also common is coolant tank splitting around the thread to the cap....

[LeeT5]

If it really is just a little bit of smoke i'd just leave it and keep an eye on it but its unrelated to the fan not working.

With respect, your version of 'a little bit of smoke' might be very different to someone elses version.

To be perfectly clear....there should be absolutely NO smoke coming from the dipstick tube, as any amount of vapours/smoke indicates that the PCV system is indeed blocked and not functioning as it should.
If the PCV blockage is not addressed on a 850 then the weakest link is the 'rear main seal' and these are known to leak because of excess pressure in the crankcase.
It only costs about £10 for the rear main seal but if the seal fails then your looking at £500 to put it right!

Cost of PCV system parts on an 850 are IIRC about £155 inc vat.

Don't wait for the seal to fail...that's foolish!

[LeeT5]

Looks like the fan is the least of my worries unfortunately! After giving the 850r a good run at speed the coolant tank is also making hissing noise once its cap is removed from the release of pressure. The coolant level is also noticeably dropping from time to time. Classic head gasket failure symptom methinks . The car was starting to overheat when I noticed the fan was not working but I didn't think that it was severe enough to cause damage like this. I'll have to book it into the local garage on Monday for a sniff test and then consider the options.

If you removed the expamsion tank cap when the engine was hot and engine running and it didn't boil over and spew its guts up, then I doubt very much that the head gasket is leaking.
If you don't know how a cooling system fuctions then your doing the right thing by taking it to the garage.
The mere fact that your cooling fan is not working tells me that you've allowed the engine to get too hot and not just on one occasion. A sniffer test will indeed detect combustion gases, if present and a cooling system pressure test will very quickly establish if there are any leaks, both internal and external. Allowing the coolant to get too hot would cause it to boil, but it would have to go about 10*C beyond 100*C before it turned to a gas and boiled because of the antifreeze in the water. However, you may or may not have been topping up with normal water and therefore the mixture will be weakened. Your garage will be able to test the coolant strength to establish it's strength.

Often overlooked is the actual expansion tank 'cap'. If this is not working correctly then the system will overheat.

[steveyruss]

If you removed the expamsion tank cap when the engine was hot and engine running and it didn't boil over and spew its guts up, then I doubt very much that the head gasket is leaking.
If you don't know how a cooling system fuctions then your doing the right thing by taking it to the garage.
The mere fact that your cooling fan is not working tells me that you've allowed the engine to get too hot and not just on one occasion. A sniffer test will indeed detect combustion gases, if present and a cooling system pressure test will very quickly establish if there are any leaks, both internal and external. Allowing the coolant to get too hot would cause it to boil, but it would have to go about 10*C beyond 100*C before it turned to a gas and boiled because of the antifreeze in the water. However, you may or may not have been topping up with normal water and therefore the mixture will be weakened. Your garage will be able to test the coolant strength to establish it's strength.

Often overlooked is the actual expansion tank 'cap'. If this is not working correctly then the system will overheat.

Thanks for the advice. I had a closer look this morning after letting the car stand. I have found a small leak coming from the radiator which accounts for the slow loss of coolant. I was worried that the loss could have been internal. When it overheated it might have cracked the radiator. The car has only overheated once according to the temperature gauge but I guess it only takes once to do some damage. Still, I feel a bit more optimistic, I'd rather have to replace the radiator than the head gasket....

[steveyruss]

So the local garage had a look at it. They confirmed that the fan motor is running fine but were incapable of finding the fault admitting they lacked expertise. The problem is clearly electrical, and I'm betting on one of the relays. They didn't even know how many relays the fan really had! I'm a bit annoyed because the garage have also triggered a warning light: "fault in engines electrical system." Apparently this is an electrical fault in either the fuel or ignition systems. I'm wondering if they were pissing around with the fuse box and did something. I can't think of any other explanations on how this has happened when they were supposed to be investigating the radiator fan! Has anyone experienced this warning light? I removed the fuses and put them back in but it wont go off. Also, there is a tiny leak in the radiator like I suspected, but I'm hoping that I can just patch it up in the mean time. Electrical faults on older cars are a money pit in my experience

[oblark]

Try pulling the ecu out overnight, that mite clear the code.

[Nealevo]

If its a relay issue, its normally the double size fan relay on top of rad o/s. Get a multi metre on it to check, I replaced mine last month with same issues

[855t5]

There is earth wire on the front of the block just by the dipstick tube take that off and clean it..mine did this cleaned the earth and all sweet again

[steveyruss]

I have just noticed that my dipped headbeams are not working. The full beam works but will not catch and stay on. It's like the dipped beams have been disabled. Good grief what have they done to my car. This is a disaster.

[steveyruss]

I had an electronics specialist look at the car. He found 3 electrical faults on the vehicle and a poorly wired starting motor. A new starting motor was put in the car recently but he said it was wired badly by the mechanic who did the job. Here the problem started with the fan, and the second garage f'ed it up even more. The car is running well again.

[Nealevo]

Damm and blast, I nearly mentioned the starter motor, when jamest5r and smithy did my manual conversion they FORGOT to connect the grey wire to starter motor (lol) so the car would over heat..

Hope its all sorted now.

[Jamest5r]

Damm and blast, I nearly mentioned the starter motor, when jamest5r and smithy did my manual conversion they FORGOT to connect the grey wire to starter motor (lol) so the car would over heat..

Hope its all sorted now.

Bastward do your own conversion next time