Xantia Water Reheater

rory_perrett · Post by **rory_perrett** » 27 Mar 2011, 22:13

Looking for what I thought was a hydraulic leak (just what you want with the MOT 2 weeks away) I found it is coming from a unit tucked behind the nearside front bumper of my Xantia HDi Exclusive. Not quite sure if it is the rubber pipe or the unit itself leaking. Tracing the pipe back was a dead lost, it goes down and then back up through the inner wing, emerges under the battery, across and under the LHM tank before disappering down the back of the engine. It seems to be diesel that is leaking, and I have concluded that this must be the reheater. Given how long it takes for the car to warm up in the morning I suspect the thing isn't working. However do these reheaters use diesel, I thought they were electric? Just want to know I'm safe cutting it. If it is the pipe that is leacking then I should able to cut enough off the end and refit. If it is the unit it is attached to, I'm I safe just plugging/seaking the end?

DickieG · Post by **DickieG** » 27 Mar 2011, 22:22

If it is diesel leaking from the water heater in the N/S/F wheelarch (they do use diesel) then there is little pressure in the plastic supply pipe (the heater has its own pump attached to it) have you considered that the leak may be coming from a rubber joint on the pipe?

rory_perrett · Post by **rory_perrett** » 27 Mar 2011, 22:34

Thanks DickieG. The leak does seem to be from the joint, not sure if it is the pipe or from the unit. Now I know it is low pressure and diesel I can have a "mess" with it and see if I can fix it. Is the heater activated by the coolant temperature or from the heated rear window switch like the heated mirrors etc.

DickieG · Post by **DickieG** » 27 Mar 2011, 22:42

rory_perrett wrote:Thanks DickieG. The leak does seem to be from the joint, not sure if it is the pipe or from the unit. Now I know it is low pressure and diesel I can have a "mess" with it and see if I can fix it. Is the heater activated by the coolant temperature or from the heated rear window switch like the heated mirrors etc.

It activated by the engine ECU according to the engine water/outside air temperature, unless you fit a separate switch as I did then you have no control over it.

HDI · Post by **HDI** » 28 Mar 2011, 10:09

When it's working it would be obvious, it sounds like a small jet engine from the outside !

Post by **Northern_Mike** » 31 Mar 2011, 16:43

HDI wrote:When it's working it would be obvious, it sounds like a small jet engine from the outside !

Aha! That's what that weird noise mine sometimes made in winter was!

Post by **Peter.N.** » 31 Mar 2011, 19:32

I have one on my 406, I didn't know when I bought it

it works a treat, I get heat from the heater within a minute of starting the car although the temperature gauge doesn't move for at least another five, or 10 even in really cold weather. One of the best features of the vehicle to me - I hate a cold car!

Peter

rory_perrett · Post by **rory_perrett** » 31 Mar 2011, 20:49

What are the conditions/ parameters required to get it to work? In the morning it is 7 to 10 miles before I get any warmth out of the heater.

Post by **Peter.N.** » 31 Mar 2011, 21:41

I think the temperature has to be below about 8C although it may be higher, the only morning I noticed it wasn't working it was 16C. The Hdi engine is very thermally efficient so in cold weather the output to the heater is very poor, which is I think why they fit them. Mine is giving a good heat output before the temp gauge even moves.

Peter

DickieG · Post by **DickieG** » 31 Mar 2011, 21:52

rory_perrett wrote:What are the conditions/ parameters required to get it to work? In the morning it is 7 to 10 miles before I get any warmth out of the heater.

It depends upon what wiring layout you have, originally they were controlled by the engine ECU to always run until the engine got up to IIRC 75°c even on hot summer days, Citroen then published a service bulletin where a thermal switch was added which prevented it operating unless the outside temperature is below 5°c, the trouble with that system is that once started the heater pretty much runs forever as it then needs to be turned off by a thermal switch inside the heater itself but the coolant never really got hot enough to turn it off.

It was because of the above I wired in an override switch so that I could control it manually, this also allowed me to get the heater going a couple of minutes quicker in the morning as the engine needs to be running for at least two minutes before the heater even starts to purge itself then eventually start.

Post by **Peter.N.** » 31 Mar 2011, 22:09

I find my heater is delivering heat within about 200 yards of leaving the house, mind you this is up a forest track so takes a minute or so, I couldn't understand it until I realized it had this 'auxiliary heater' It doesn't mention it the handbook or the Haynes manual. Its about 4 miles before the temp gauge is halfway up. I think mine must be turning off OK because its doing around 60 mpg on a longish journey, I went to cornwall last night and it managed 61.5 mpg. Its a brilliant thing to have - well it is to me anyway, but I'm cold most of the time.

Peter

rory_perrett · Post by **rory_perrett** » 31 Mar 2011, 22:19

I'm going to have to have a go at sorting mine out in eager anticipation of a cold and miserable summer. Mind you I won't be buying any new parts as I bet these are all dealer only. Will be a while need to get through the MOT first. List so far o/s lower wishbone (did n/s last weekend). N/S track rod and probably the o/s as well. Rear brakes need a look at, suspect the dreaded corrosion is canting the caliper over and a quick check of the back exhaust box as it was an advisory for corrosion last year, sounds fine to me but needs checking out.

Post by **Peter.N.** » 31 Mar 2011, 22:38

There are a few of these units for sale on ebay, but they seem to make about £100.00 - depends how much you like your warmth. The aircon has packed up on mine but it rarely gets to hot for me in this country.

Peter

mongoose100 · Post by **mongoose100** » 01 Apr 2011, 05:12

Just how efficient are these things? Might look at retrofitting one to a caravan just to take the edge off a freezing night!!!

Do the V6's have something similar?

DickieG · Post by **DickieG** » 01 Apr 2011, 07:35

rory_perrett wrote:I'm going to have to have a go at sorting mine out in eager anticipation of a cold and miserable summer. Mind you I won't be buying any new parts as I bet these are all dealer only.

You can buy quite a number of parts for these from VW dealers as they're fitted to the T4 Transporter minibus and Sharan/Galaxy's not to mention a number of seller's offering parts on Ebay as well as others offering to service them for under £100. More than likely the glow plug is U/S in which case GSF sell those, the unit may also have excess soot in the gauze around the glow plug which causes clogging/non lighting then the unit flooding itself.

These heaters use a minuscule amount of fuel so won't noticeably affect fuel consumption figures even if they are constantly running, however the electric fan motors' life cycle will be somewhat shortened, not to mention the gauze issue mentioned above.

These heaters were only fitted to HDi's due to their thermal efficiency, the downside to them on cold winter mornings is the delay of two minutes engine running followed the time it takes them to go through their purging process before they even light up and start producing heat, great boys toys though!.