A/C Condensor fan always on.

[Scandi]

Hi,

I have a Defender 2004 TD5 with air conditioner.

The gas is gone as I have a leaking condenser but climate is such that haven't had the need to use it.

The fan in front of the condenser is however always on once the engine is running despite the A/C being switched off.

Is this normal, as I can't see the point of it being on if A/C is not on?

Lars

Nairobi, Kenya

[Ally V8]

This happens when the engine has been overheated. There won't be any faults logged showing it, but if it is put on a diagnostic machine such as Testbook or Nanocom,and a fault code clear is performed,the fan will stop.

[Scandi]

Thanks a lot for that input Ally V8.

I did a quick and dirty by removing the relay but will now so the right thing.

 

[Scandi]

I had the faults cleared and the fan stopped,

A couple of days later the damn thing came on again and I'm sure there was no engine overheating.

Are there other things that may cause this to happen?

Lars

[Ally V8]

You need to hook up a diagnostic tool and watch the coolant temp as the engine ecu see's it. The gauge will not move above normal until its way too late.Overtemp is the only reason I've ever seen for the condensor fans to stay on.

[Scandi]

15 hours ago, Ally V8 said:

You need to hook up a diagnostic tool and watch the coolant temp as the engine ecu see's it. The gauge will not move above normal until its way too late.Overtemp is the only reason I've ever seen for the condensor fans to stay on.

Today I made an interesting observation.While driving I noted a slight loss of power, perhaps just a second or two, as if I would release the throttle a little bit and then push it down again.

at the same time just by chance I was looking at the instrument panel and noted the temperature gauge flying up into red and then immediately down to normal again matching the loss of power I noted. I'm talking of a duration of 1-2 seconds only.

I also note it takes a very long time to get heat going and coming out of the vents even if engine gauge shows it's warm.

When checking coolant level it was low and I had to add some 2-3 liters to get it up to level.

I'm suspecting this may be reason to the sudden and momentary rise of temperature as if there has been an airlock and parts of the cylinder head has heated up due to low level and suddenly a slug of coolant is gets in contact with the hot surfaces and gets very hot and reaches the temp sensor for that short time i noted the gauge flip out.

It may also explain why the heater isn't coming in as quickly as desired since the coolantdoesn't get there if pipes are empty.

Does this make sense?

Is the lack of power I noted perhaps a consequence of the ECU thinking the engine is overheating and making it power down as a precaution not to have it overheat further?

[Ally V8]

Yep, its trying to limit engine damage by limiting power output when it see's the overheat situation.Must have saved loads of engines ! What I don't understand is why they didn't allocate a fault code to it when they wrote the software. I think you need to investigate the coolant loss,pressure testing when cold will show any small leaks that escape as steam when hot. If there are no external leaks, a blown headgasket is a likely cause...

[Snagger]

It sounds like you have an electrical issue, either a bad connection on the sender or gauge hiding high temperatures due to the poor electrical connection, or more likely, an intermittent short that you're seeing on the gauge which is making the ECU think there is an overheat.

[Scandi]

At the moment I'm leaning towards having a coolant leak/low level issue rather than something electrical.

  I can confirm the heater coming on a lot quicker than before, after topping up the coolant. In fact I notice hot air well before the gauge reaches "steady state".

I'm going to check for possible leaks but the tell-tale smell of leaking coolant is absent so hope it's because of being tiny instead of being internal.

 

[Snagger]

I don't think Defender TD5 heads fail often if the engine is standard, but if it has been tuned, then it is more common.  Still, the usual problem is manifold studs being ripped out.  It's probably just a head gasket if it's internal.  I understand that the fuel heat exchanger can have problems, though, and that uses engine coolant.  A tiny leak in that could be contaminating the return line fuel with coolant.  I'd drain the tank or the sedimenter into a glass jar to check for water.

[Ally V8]

The heads themselves tend to crack in #1 inlet port,but its not that common. They also crack around the bore where the unit injectors sit - I have 2 heads in my workshop like this at the moment.Head gasket failure due to coolant loss is quite common,for all the usual reasons,small unnoticed coolant leaks,blocked radiators etc. I have one on the ramp at the moment with a pin hole in a coolant hose,enough to wreck an engine on a long motorway journey. They also suffer head gasket failure from the head not being located correctly because some clever oik decided plastic locating dowels were a good idea... Steel ones fix that.Failure of the oil cooler will show up by oil in the water,failure of the fuel cooler is normally an external leak. They can be difficult to accurately diagnose with coolant loss,often will run for a while using nothing,then swallow a litre or so on a short journey. A cold pressure test will show external leaks,but often sniffing in the header tank for hydrocarbons will not reaveal the normal gases present with gasket failure. If it can't be explained with a cold pressure test or sniff test, then its best to take it apart and inspect the gasket before any serious damage occurs.

[Scandi]

My engine is fitted with a Turbotechnics VNT and the ECU has been remapped by Bellauto but with a little less fuel than standard since I'm operating sometimes at 2,500m altitude.

I will start by looking for external leaks to start with and if coolant still escapes, work myself towards the interior.

Whatever I find (or not) will be posted here.

 

[Snagger]

I thought a 2004 vehicle would be certain to have steel dowels - I though LR realised the stupidity of their ways after just a year or two.

[Scandi]

Maybe they are just trying to save on weight with those plastic bits:-)

 

[Ally V8]

14 hours ago, Snagger said:

I thought a 2004 vehicle would be certain to have steel dowels - I though LR realised the stupidity of their ways after just a year or two.

Unless Scandi has owned or known the vehicles history from new,it could have either fitted. So many TD5's have had engine swaps because people are scared to take them apart.Often Defenders end up with engines out of Discoveries where the chassis has rotted out. The youngest TD5 is now 10 years old so i tend to treat each one as an individual,deal with whatever I find when it comes apart..

I was just trying to add hopefully useful data for anyone who reads this thread,trying to find info for a similar issue.