Fans on nearly all the time!
Discussion
I know I should have paid attention to all those previous messages on heating and otter switches - but sorry!
My 95 4.0 Chim always used to run about 75 degrees. The fans would kick on around 80 and in traffice it never got above 90. However, the original rad sprang a leak and a main dealer fiited a new one under warranty. The new one has a hole for a temp sensor in the lhs of the rad but, since my car has a sensor in a swirl chamber, the hole in the rad is blanked off by a spare sensor which is unconnected. Apparently this is standard practice for a new rad on an old car.
However, the car now runs sligtly hotter at about 78 (no great shakes there), but every time I stop, even after a run with a clear road and no traffic, the fans always seem to be on. The fans are never on when the engine is cold and only come on after it heats up properly. If I get stuck in traffic, the temperature still doesn't get above 90. If I shut down the engine but turn the ignition back on, the fans usually run for about 3 minutes before switching off.
Therefore, I am not worried about overheating but I want to know why my fans always seem to be on with normal running. Is a switch just kicking the fans on too early?
What can I look at? Where is it? (Sorry, no bible ATT).
Thanks for any advice.
My 95 4.0 Chim always used to run about 75 degrees. The fans would kick on around 80 and in traffice it never got above 90. However, the original rad sprang a leak and a main dealer fiited a new one under warranty. The new one has a hole for a temp sensor in the lhs of the rad but, since my car has a sensor in a swirl chamber, the hole in the rad is blanked off by a spare sensor which is unconnected. Apparently this is standard practice for a new rad on an old car.
However, the car now runs sligtly hotter at about 78 (no great shakes there), but every time I stop, even after a run with a clear road and no traffic, the fans always seem to be on. The fans are never on when the engine is cold and only come on after it heats up properly. If I get stuck in traffic, the temperature still doesn't get above 90. If I shut down the engine but turn the ignition back on, the fans usually run for about 3 minutes before switching off.
Therefore, I am not worried about overheating but I want to know why my fans always seem to be on with normal running. Is a switch just kicking the fans on too early?
What can I look at? Where is it? (Sorry, no bible ATT).
Thanks for any advice.
I don't think I've been on a single journey in mine without the fans starting a few times.
Coming on at about 80 (mine does) and temperature never really going over 90 (mine reaches about 95) looks normal. The fact that with your new radiator the car is running a few degrees hotter is the key here. As the new normal running temperature is very close to the point the fans switch on, I would think that is why they're now coming on a lot more.
Coming on at about 80 (mine does) and temperature never really going over 90 (mine reaches about 95) looks normal. The fact that with your new radiator the car is running a few degrees hotter is the key here. As the new normal running temperature is very close to the point the fans switch on, I would think that is why they're now coming on a lot more.
On my '99 450 the fans cycle on and off through all journeys, but never had them constantly on even in the hottest weather (unless crawling). If it sits idling the fans will come on but then go off again after about 1-2 mins once the water temp falls. 
I wonder if your otter switch is faulty and coming on to early.
I wonder if your otter switch is faulty and coming on to early.everitj said:
Sounds like a new radiator is needed. Mine used to be like that until i changed it, now the fans only run if its been sitting for a while. Never goes above 90, normally runs around the 80 mark...
Guess you didn't make it past the first line of the second paragraph of the original post
Thanks everyone for your replies so far. To clarify, the fans do their job ok (as does my NEW rad!) but they only used to come on if I got stuck in traffic. Now they just seem to be on all the time, as soon as the car warms up. Can't do the life expectancy of the fans any good!
So where is this otter switch then and how do I check it? Can you honestly get a lower temperature otter switch (in which case do I need to get a slightly higher one)?
So where is this otter switch then and how do I check it? Can you honestly get a lower temperature otter switch (in which case do I need to get a slightly higher one)?
Chris Smith said:
But is it ok for the fans to be running nearly all the time? Surely that can't do them any good??? The other day it was pretty cold and the fans were still on.
I'm going to buck the trend and agree with you, IMHO the system should either work properly or there's a problem (and my approach is that that goes for all systems). There's no way that the fans should be on vitually all of the time and besides which the noise is irritating.
You will need first to establish what the actual water temperature is (the gauge is too imprecise for this) and then decide whether the otter switch is operating properly. The alternative would be to substitute the switch with a known good one and see if that solves it.
Chris Smith said:
But is it ok for the fans to be running nearly all the time? Surely that can't do them any good??? The other day it was pretty cold and the fans were still on.
Sorry, I got a bit confused by your initial post, you start by saying that the fans come on when you stop, then you say they are on with normal running.. do you mean that they are on all the time with normal running or just on and off with normal running..?? If they are on all the time then indeed something is not quite right.. I'd start by replacing your otter switch (£12 and a 10 minute job) and seeing if that solves it.
Cheers,
Matt.
Big Al. said:
So where is the Otter switch? (must get a bible!!)
IIRC on the later models it sits under the Swirl Pot.
Indeed
Early one, in the bottom of the Swirl Pot, later ones sort of underneath it. Easy to change and you can do it without bleeding the system too if you're confident about it (you'll still have to top up though as you'll loose half a pint)
Chris,
I have pretty much exactly the same symptoms as yourself and pretty much the same history.
My rad was repaired over the summer (stone-holed) and while putting it back the otter switch was "upgraded". At the time the dealership showed me that it was working by using an infra-red sensor on the pipes as the fans kicked in an turned off (at 80 and 70 degrees respectively IIRC).
Since then my fans have been running a lot more than before, causing me minor worries about the longevity of the fuses. It's not something that is really concerning me though.
BTW, my otter switch is at the top, nearside of the radiator.
I have pretty much exactly the same symptoms as yourself and pretty much the same history.
My rad was repaired over the summer (stone-holed) and while putting it back the otter switch was "upgraded". At the time the dealership showed me that it was working by using an infra-red sensor on the pipes as the fans kicked in an turned off (at 80 and 70 degrees respectively IIRC).
Since then my fans have been running a lot more than before, causing me minor worries about the longevity of the fuses. It's not something that is really concerning me though.
BTW, my otter switch is at the top, nearside of the radiator.
Ah-ha, now I know where the Otter switch is! I just thought this was the temperature sender. In that case I now have 2!!! There is one in my swirl pot that has wires going on to the connectors. However, because the garage fitted a later style rad, they blanked off the hole in the rad for later style cars with another switch.
Presumably, therefore, I can simply try changing these 2 switches over????? If so, how tight should you do the switch up to when you put it in?
Alternatively, I could extend the wires from the swirl pot switch to the radiator one. Is there any reason why I shouldn't do this?
Presumably, therefore, I can simply try changing these 2 switches over????? If so, how tight should you do the switch up to when you put it in?
Alternatively, I could extend the wires from the swirl pot switch to the radiator one. Is there any reason why I shouldn't do this?
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