Fan Switch, Where Is It?
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rewmer
Well-Known Member
- Posts
- 2,082
- Location
- Clacton, Essex, UK
There is no manual control for the Air con fans, which I assume you are talking about. However, they should kick in if you are getting really hot. It would be a good idea to fix the problem though, rather than try and work around it. A cooked engine can be very expensive. If you are overheating when stationary, its a fair bet the viscous coupling has or is failing. Dont be tempted by a second hand unit from a breakers, buy new. No part part of the cooling system is very expensive, if its suspect - replace it. Dont take chances.
Hi, have just done my viscous fan today, very easy job only half hour and only £66 from island 4x4 but beware mine is a 1999 4.6 V8 and its a right hand nut NOT a left hand as stated in some workshop manuals. It has not cured the problem but good to have a new one so have put a post on here to see if it might be the rad. Paul
If anyone has any views all are most wellcome (sorry I'm highjacking your post!!)
If anyone has any views all are most wellcome (sorry I'm highjacking your post!!)
rewmer
Well-Known Member
- Posts
- 2,082
- Location
- Clacton, Essex, UK
Nce to hear you have sorted the old girl out. It certainly wouldnt hurt to give the rad a flush out as well. These cooling systems have to work realy hard and one small problem, and the tempreture rises - as you have found.
kimbo4x4
New Member
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- 8
- Location
- Central Scotland
I believe the electric fans only kick in when
1. Air conditioning requires gas passing through system cooled - heat transfer etc.
2. If gearbox oil temperature sensor detects things are getting a bit hot !
Under normal circumstances air flow over a V8 whist on the move will keep it cool as long as coolant is circulating through radiator. If you have a trailer stick it on the back then tow it up a steep hill - that will test the cooling.
1. Air conditioning requires gas passing through system cooled - heat transfer etc.
2. If gearbox oil temperature sensor detects things are getting a bit hot !
Under normal circumstances air flow over a V8 whist on the move will keep it cool as long as coolant is circulating through radiator. If you have a trailer stick it on the back then tow it up a steep hill - that will test the cooling.
Hi, had to change the rad today as just replacing the viscous fan did not work, easy job but even easier if you do it while replacing the fan. I can say all is now ok, at last. The advice is as other members said the parts arn't that expensive so do it all while your hands are dirty. Paul
Right, I can leave the vehicle ticking over for hours with no problems, I could probably drive the lenght and breadth of the country with no problems but if I put the boot down it instantly over heats.
Basically I drove home from work last night which is a good 15 miles and over various terrains being out in the sticks. So I was up and down hills with no problems, long stretches of straight county roads topping 60 mph, still no problems, but coming up a very steep hill in the village the car infront of me turned so I slowed to an almost stop before flooring it to get some speed up for the hill and it's then when it overheated.
The gauge went up quickly and the light came on but as soon as I passed the crest of the hill and started the descent the temp came down almost as fast as it went up. I then had another steep hill to climb before pulling on to my drive where the temp had risen again and the contents of the expansion tank were emptying all over my drive.
I have been as descriptive as i possibly can and I hope there is someone out there who can shed some light on this for me, please?
Thanks in advance.
Basically I drove home from work last night which is a good 15 miles and over various terrains being out in the sticks. So I was up and down hills with no problems, long stretches of straight county roads topping 60 mph, still no problems, but coming up a very steep hill in the village the car infront of me turned so I slowed to an almost stop before flooring it to get some speed up for the hill and it's then when it overheated.
The gauge went up quickly and the light came on but as soon as I passed the crest of the hill and started the descent the temp came down almost as fast as it went up. I then had another steep hill to climb before pulling on to my drive where the temp had risen again and the contents of the expansion tank were emptying all over my drive.
I have been as descriptive as i possibly can and I hope there is someone out there who can shed some light on this for me, please?
Thanks in advance.
jorjio_k
Active Member
- Posts
- 490
- Location
- Lebanon,middle east
Sorry for what ur having.having ur temp rising and droping is not an indication of hg blown,u have a problem in the weater circulation,start by flushing ur radiator coz a blocked radiator will overheat the engine on steep hills.morning time b4 u start the beast open the cap of the water tank,start it up and see if the water is returning to it,if no water returning it means:
1.blocked hose or hoses
2.water pump failure (not circulating the water)
close ur cap after checking the flow of water,keep ur engine running at idle,wait 4 20 min aprox,then touch the bottom hose of the rad if it is cold it means that the thermostat is seized in the closed position thus not allowing the water 2 circulate in the rad for additional cooling.
a hard rad top hose means pressure is build in the system (it can get hard also even if ur hg isn't blown=water pump) blocked water circulation.
do u have oil in the coolant?do u have coolant in the oil?white stuff like mayonaise on the oil stick or under the engine oil cap?these r signs of bhg.
if high milage in done in ur car:
replace ur rad
replace viscous fan
replace hoses
replace thermostat
replace expansion tank cap
replace water pump
these are the first things to start with b4 changing the hg,or checking for slipped liners.:doh:
good luck
- Posts
- 58,170
- Location
- Preston Lancs.
Electric aircon fans have no function as engine coolers, unless they have been rigged to act as such by fitting a thermostat in the top hose and switching them through a relay. Their only function is to cool the aircon radiator when the aircon system demands it. The switch to operate them is contained within the aircon system and cannot be affected by engine temperature.
ssmn1234
Active Member
- Posts
- 691
- Location
- Cairns, Australia.
the condensor fans run continueously while ever the air-con is running, if they aren't running and your cooling system is marginal, then you can over heat your engine. If they dont come on then check there is power getting to them by using multi-meter or test light on the electric cable somewhere close to them when air-con running, could be burnt out fans or faulty relay. my money is on the viscous head being lazy causing most of the issue, as stated above, they are cheap and easy to replace.
- Posts
- 58,170
- Location
- Preston Lancs.
It is obviously a lot warmer over there than it is here, if your aircon fans run continuously. They are controlled by a temperature switch in the aircon system. They only run as required by the aircon to cool the refridgerant. Whilst they also cool the engine to some degree while they are running they are not there for that purpose. The engine temperature does not control them. In fact on the P38 if the engine temperature gets too high, the aircon compressor should be disconnected automatically by the ECU to reduce the load on the engine until the temperature returns to normal.
