this might help...... (pics on link)
Cabin Heater
I've been the very happy owner of a 1998 Silver Freelander XEDi for around 3 months now, nothing but praise for it really, totally impressed. However I was pretty amazed for the type of vehicle this is that when the autumn came and I started turning the heater dial away from full cold and didn't use the A/C all the time that nothing came out. After about 15 mins I did get a little heat, but nothing to write home about. I first thought the heater matrix must be blocked, great job to change that looked ! but when I pulled the hoses off I found I could put water through it easily with a hose-pipe. Next I thought it must have got an airlock as I'd topped up the coolant recently, so I carefully topped it up again with the heater bleed valve open and made sure it was totally full. This was better, but still took 5-10 minutes to get warm and would sometimes lose its heat depending on driving conditions. So I looked further ...
As you may see from this cooling system diagram the heater matrix is plumbed in parallel with the EGR (exhaust gas recirculation) valve and is fed with water into the lower part of the matrix. It would seem that as soon as even a tiny amount of air enters the system the flow through the matrix will be impaired, and at best the flow isn't great as the route down to the EGR is much easier - good old gravity ! I had a good check of the pipes during a couple of mornings runs to work, jumping out every five minutes and feeling the relevant hoses and it was obvious that the heater got very little flow compared to the rest of the circuits. I set about a plan to improve this.
Basically I have moved the pipes so that rather than the EGR and heater being in parallel they are now in series. The water flows into the EGR valve, out of that on a new hose I have installed and to the top pipe of the heater, then out of that and return via the normal pipe. I used a foot of 16mm heater hose, two jubilee clips and two 15mm copper pipes made into stoppers. Actual pipe-work should take you around 15 minutes ! My only concern was the flow out of the IRD cooler, but on looking at this the flow for that remains exactly the same relative to the other items in the system.
The results were amazing, total transformation of the heater system. I now get warm air within two minutes of driving off and full heat in around five minutes. For the first time I even have to turn the dial off full heat whilst driving !
Note : this seems to apply in part to the 1.8 petrol engined vehicles also, but the heater is bypassed by the IRD circuit which takes a little more re-plumbing to make it run in series correctly - I'm sure it could be done though.
