Hi All

I have a query on the operation of the heater matrix in my Disco 2 4.0 with aircon. I recently noticed that the heater matrix always have hot coolant pumped through it and therefore it is always boiling hot. According to the workshop manual this is normal and there is no valve in the coolant feed or return pipes.

The problem I'm having is that it is so hot that the centre console is getting really hot I burnt my leg on it wearing shorts over the weekend. It is also kicking out a lot of heat and the drivers side footwell is really hot. Also footwell air ducts are very close to the heater matrix and they are getting warm resulting in hot air being blown out even when the air conditioning is on cold. Every other vent seems to work OK and i've looked at the servos on the heater assembly and they are all working OK and the blend valves appear to be operating normally.

Any thoughts on this welcome - is it a design flaw and normal operation?

Thanks, Paul
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Check that you aircon drain pipes are not blocked. If they are, the conndensation from the aircon can't get out the bottom, and can end up collecting round the heater pipes. It then acts as a nice conductor to bring the heat out.

I had this happen on a long journey off road in Zimbabwe - aircon was on but my feet were getting hot, and the car was steaming up. Also the carpets at the side of the gearbox tunnel were hot and damp.

Drains are two pipes either side of the gearbox, with a "squid-like" plug. This is supposed to let water out and keep the dust out. But the dust and water can easily turn to mud and block the tubes.

With the car cool (you have to reach round the exhaust), crawl under the car, and the pipes are either side of the gearbox, about level with the gear lever. Wearing old clothes (you will get an armful of dirty water and a faceful of dust), pull out the squid like plugs, and I suspect a load of water will come out. Clean the plug and refit. Repeat other side.

Hope that's your problem - it's a very common Disco I and II problem, and a really cheap fix!

Cheers!

Thanks Graham, I'll check it today. I was going to change the gearboix oil and filter so I'll be filthy anyway!

I found the resolution to this.

Behind the centre console sits the heater matrix. It is sealed by a foam gasket. The gasket had failed and lettinghot air blow out continuously into the footwell. I sealed this with some sealant and all is now fine!

Nothing to do with a dodgy earth for the electrics say? I only notice the console getting hot when I use the blower (aircon needs regassing). When I've driven without using the fan then it doesn't seem to get anywhere near as hot.

Thanks.