Thread: 300Tdi Air Conditioning Fan will not shut down

Originally Posted by Judo

Rob, I'm on my phone so perhaps I've not understood, but it sounded like you had just installed some new wiring.

It was fine, then without any changes it started happening?

Apologies Judo, it started happening before I changed the sensors, literally out of the blue.

I changed the sensors last night in a bid to restore it back to "normal" operation and this has not suceeded.

Rob

Originally Posted by Overland_110

I built the land rover from the ground up and sourced a Rest of the World spec loom which means I have a late Td5 style dash and electrics (still no engine ecu though).

I was talking about this, but based on your replies, I assume you didn't install the new loom recently.

Does your A/C work when the fans are on?

I just had a quick look at the workshop manual and if you had an overheating problem, then I believe 2 things would be happening:

1. A/C would not work once the fans started. (thus my above questions).
2. The fans would continue running for 10 minutes after you turn the vehicle off.

Of course with your non-standard wiring, these may not be true, but that's the case for a standard 300TDI.

The twin electric fans on my 300Tdi D1 run all the time the air-con is on - always have. I just assumed this was normal.

Originally Posted by DiscoMick

The twin electric fans on my 300Tdi D1 run all the time the air-con is on - always have. I just assumed this was normal.

That is normal.

Rob's fans run even when the air con is off.

OK, a bit more information. Last night I replaced the viscous fan unit witha new one as I suspected that it wasn't "locking-up" when hot.Anyway, I am not sure if this made much difference as the electric fan stillcame on when the temperature gauge was reading "normal".

Once this happened I removed both the yellow and the green plugs from theswitches. The fan stopped when the yellow was removed. I could also hear thecompressor "clicking" when the green was removed, though not a 100%sure. I checked the fuses and they were good, I also checked the two relaysunder the driver’s seat (ROW Spec loom again) and these appeared to be openingand closing when the fan was discounted and reconnected in the engine bay.

My thoughts:

The engine has done around 3600 miles since it was fitted (reconditioned inthe UK, by Turner Engineering). My rad is a 4 core HD one, (replaced the sametime as the engine). Also worth noting all the ancillaries were replaced aswell; water pump (new, genuine), new turbo, etc.

About the only thing I can think of is that perhaps I have an airlock in thesystem? The rad certainly isn’t blocked and the condenser is fine. In view ofthis I am going to give the system a really good flush, but what is the bestway to refill a Defender cooling system to ensure no airlocks.

I still don’t understand why this has started happening though. Also, doesanyone know of a good aftermarket temp gauge that I can fit into my thermostathousing to measure the temperature more accurately than the Land Rover gauge.

Regards

Rob

VDO gauges are the same size as your factory dash one and the sender will also fit into the factory sender thread if you buy the mechanical gauge. Electric gauges can also be used, just make sure the thread of the sender is right.

1/8 inch - 27NPTF thread

Temperature Gauge - Mechanical Water

If you believe it is an overheating problem but radiator, water pump etc are new, you could take out and test your thermomstat. Maybe it's not opening. That would explain why it takes ~10 minutes of driving before heating up.

Originally Posted by Judo

VDO gauges are the same size as your factory dash one and the sender will also fit into the factory sender thread if you buy the mechanical gauge. Electric gauges can also be used, just make sure the thread of the sender is right.

1/8 inch - 27NPTF thread

Temperature Gauge - Mechanical Water

If you believe it is an overheating problem but radiator, water pump etc are new, you could take out and test your thermomstat. Maybe it's not opening. That would explain why it takes ~10 minutes of driving before heating up.

Judo,

I forgot to explain I also replaced the thermostat with a new "waxstat" (genuine part I think) last night. This also had no effect on stopping the fan.

Rob