Air conditioner fans and engine temp

[Hendrous]

G'day all,

Since putting an engine temp gauge on I've noticed a fairly big jump in temp hen I put the air conditioner on.
Normal running temp seems to be about 83 degrees, but with the air conditioner running on a warm day y'day the gauge jumped to 92 fairly quickly. Is this anything to worry about?
Also I'm wondering how the fans at the front of the grill work? At what point are they meant to spring into action. Looking at them today with the air con running they were doing nothing, but the engine wasn't above 86.
Any ideas on how i can test the fans are working and troubleshoot a problem would be appreciated. I'm set to go north with my wife and kids in a few days and I can just see my wife's face when I tell her we can only use the air conditioner when it isn't really hot in the car.;)

[PhilipA]

On a RRC the fans turn on at 102C and off at AFAIR 96C.
I am pretty sure that a D1 would be the same.
I have only seen mine go on once on the Mt Pinnibar climb on a 37C day.
BTW a D1 v8 should run at over 88C all the time except for a very cold morning.
The fans on an RRC work all the time that the aircon is turned on whether the compressor is operating or not. I don't know whether later D1s are different but I think not.
So I would be checking whether the fans work by hot wiring them to the battery. You could first check them with the engine running by bridging the switch on the thermostat housing.

Regards Philip A

[omvanders]

All sounds pretty normal to me as far as increased temps go, although the rise may be a bit exaggerated if the front fans are not working. Then again mine weren't working for the first 18 months I owned the D1 and yet I never had any real issues, given that rest of my cooling system was in good nick. A good radiator and hoses are essential.

And yes, the fans should come on as soon as you flick the AC on.

[Discomark]

i'm pretty sure mine come on as soon as the aircon is turned on as well, regardless of the temperature.
The relay for the fans is at the back of the glove box and I connected a switch so I can turn them on without the aircon on.

[Uglitom]

Disco v8 electric fans are supposed to come on when the air con is switched on and when the engine temp is getting high (I don't recall the specific temp).
I have certainly had mine come on after some hard sand driving ( I don't often use the aircon - too stingy).

[Hendrous]

Thanks fellas,

Reading the manual it does mention a temp sensor to regulate the fans so that implies they are designed to flick on at some point, but from the sounds of it, on some D1's they just run when the air con is turned on.

As my air con struggled last summer on the hottest days I figure i need them turning whenever the air is switchd on. Can't hurt can it and it should help the radiator out.
Now to figure out how i sort it. Unfortunately I'm next to useless when it comes to electrics. Eg assuming I can find the relay switch, how do I proceed from there, do I give it a slight bash with something as per the old tv method, or do I attempt to check it with a multimeter which I barely know how to read or use. Hmmm...this is where I'm inclined to start from scratch and wire some new fans up independently and stick a switch on the dash or find a power source related to the internal air con fan- i know that is working.

Any ideas (or warnings) most appreciated.

Chrs

Mark

[PhilipA]

Reading the manual it does mention a temp sensor to regulate the fans so that
implies they are designed to flick on at some point, but from the sounds of it,
on some D1's they just run when the air con is turned on.

Mate, the fans have 2 purposes.
One is to cool the condenser for the aircon, so they go on all the time the aircon is on.
Second is to help the engine viscous fan when theengine gets really hot to avoid damage.
There are two separate switching circuits.

If you are not confident to do the couple of tests that I have suggested , you really should take it to a Land Rover specialist to be sorted out.
Regards Philip A

[Discomark]

Hi Hendrous,

I couldn't find a way of adding an attachment to the PM so here is the pic of the relay and thin black wire you need to ground to turn the condensor fans on.

Cheers
Mark

[98discovery]

For what its worth I had to replace both of mine several years ago when I purchased the vehicle.The fans are a sealed non maintainable part so I bought two second hand units.
I didn't have any cooling issues but was aware of the potential risk of overheating due to the dodgy temp gauge so thought it a worthwhile investment to replace them.
As outlined previously they operate off two independent circuits.Are they spinning freely? One of mine wasn't as it had a bunch of bugs leaves etc jammed behind it.
Another quick way to test them is to unplug each fan and test with a multimeter firstly that you have 12V at the supply wiring plug (A/C on) and secondly resistance across the fan (unplugged of course).This will quickly establish if you are getting power to the fans with the A/C turned on and if so whether the fan is open circuited as both mine were.
From memory the plugs were ok to access and I managed to change the fans out by removing the grill with a bit of patience.

[Hendrous]

Yep I agree it does take some patience getting the old fans out. The one on the left facing the grill I found you can drop down after getting the hard to get at screws loose. The one of the right was more problematic. I found it had to go up and out and so you have to undo the oil cooler on the right side and pull it out by about an inch or so and also take out the strut connecting to the bonnet lock.Maybe there is an easier way to do it?
For replacements I got two 12 inch fans from a mob on ebay for $25 ea and cut them down to fit into the old housings..Not my intention when I bought them but when they arrived I discovered they were too big by about an inch. There is a lesson there somewhere- measure before ordering.. Anyway the benefit of doing the modification this way is they go back in snug because you are using the original landy housing
Mark, thanks for the pic, I'll definitely have a go at wiring in a switch so i can use the fans when crawling up hills this summer.

So far I haven't had a chance to really test the engine temp on a warm day to see if getting the fans working has made a difference, but I'll report back if it seems to improve things. The air con does seem to be blowing cooler air.

Chrs

Mark

[angus1]

As PhilipA says the fans come on at 102C, OR when the aircon is switched on. More important is to make sure the viscous fan is working properly. I went two years trying to fix overheating problems until replacing the viscous unit!!!!

[Fraser7919]

Very good advice. It's very difficult to pickup a problem with the viscous fan visually. I had a similar problem which took some head scratching to figure out.

[theNEWT]

What engine v8 or diesel? My 300 Tdi increases temp by 4-5C with AC on. The fans come on with the AC, they work together and the fans come on if temps get too high to assist the viscous fan...havent tested to see at what temp.

[Blknight.aus]

the fans are supposed to come on automatically over 100 deg C (or thereabouts) by means of a break/make temp sensitive switch in the outlet of the engine between the thermostat and the radiator.

they should come on anytime that the AC pump is engaged

its normal for the temp to come up when they are on 1. extra load on the engine 2. extra heat in front of the radiator. Sometimes its also caused by electrical load kicking the voltage to the gauges/sensors around. easy to spot the temperature jumps the same amount every time the compressor cycles

[Fausto79]

One of the plugs that goes into the u pipe at my thermostat housing has been unplugged and taped since ive had the car. Does this mean that:
1. It's not turning fans on when ac is on?
2. It's not switching on when it hits the high temps?

the fans definitely come on when i turn ac on so point 1 above cancels out.
Is the other plug for the high temp sensor then and my fan will not kick in at all when engine hits the high temp mark?

[Fausto79]

UPDATE: pulled tape off around the loose plug and someone has put a jumper between the teminals. What would this achieve? Just continuation of circuit so that you don't get earth issues?

Heres a pic.

[Blknight.aus]

one of the switches turns the AC compressor off as the engine gets into "hot" territory, this is the one that seems to have been bypassed in your case, the other one bypasses all the AC settings and tries to turn the Thermo fans at the front on.