www.jec.org.uk

I went to put the heat on today as it was a little chilly, and....

nothing. no matter what buttons I pushed I can get no heat at all (that I can feel anyway) into the cabin - any ideas? Maybe I am doing something wrong? all the fans seem to work fine and The previous owner never mentioned any problems - and I assumed because the air-con was working the "other way" would be fine as well

coming into winter and with a very limited budget to fix any problems I hope there is something simple I can look at.

on another note, where should the temp gauge be sitting usually?

EDIT:
Just to update, I had a quick look around the internet and some places mention to check the fog light fuse, and my fog lights are working ok.

If its at the correct temperature it should be stood to attention up the middle........just a note you are running the engine a while before looking at the temp gauge eh?.........Joe

Hi bmc,

Assuming you have checked the coolant levels and have squeezed both hoses with the header tank cap off to make sure there are no air locks, the most likely reason for no heat is that the electric water pump has failed. This pump is used to circulate water continuously through the heater matrix from the engine block so that i) before the engine main thermostat opens you can get some heat and ii) because at low engine rpm the main pump does not circulate enough water around the minor heater loop.

Have you checked if you get heat at motorway speeds, i.e. engine above 2000 rpm? If you set the heat all the way up beyond 31deg C to "Hi" then above 2000 rpm you should suddenly start to get loads of heat. If you do then this will confirm that the pump is the culprit. (The other possible problem, although less likely, is that the four-way valve has stuck. This valve allows water through the heater matrix or returns it to the engine if not required, and usually cycles open/close on a 6-second interval. On "Hi" the valve should be fully open and not cycling)

The pump failure is a common problem, because the motor runs all the time the ignition is on (Climate Control blends hot and cold air to get the desired temperature and humidity level) and after several years the motor carbon brushes wear out. The pump is quite easy to get at, and if you are feeling rich then you could get a whole new pump from your Jaguar main dealer (about £260 at the last count!) or you could try and find a second-hand one - but that may not have much life left in the brushes.

Unfortunately brushes are not available as spares however, if you are fairly handy you can take the motor apart and make new carbon brushes (I modified some that I got from a washing machine spares shop). This process is detailed on the Jag-Lovers site (http://www.jag-lovers.org) by several people including me. If you don't know about this site you will have to register (it's free) and then you can search for the posts dealing with the brush replacement - some of these have good pictures. Search the X300 X308 archives for "heater pump brushes" or similar.

Good Luck!

I just went to check the coolant levels while she was cold, and the expansion tank is full of the usual old dirty brown water I'm used to seeing in my old rovers. Obviously no antifreeze in there for a while! I'm getting that flushed out asap and the correct antifreeze solution put in - thankfully there is no sign of any oil in the water or "mayo" on the oil dipstick

the temp gauge (sort of a half circle on its side) seems to be sitting just below the 3/4 up mark and does not go above that point, there are no warning lights or coolant smells either. It all reminds me of my old rover V8 as it did that as well.

Does anybody do reconditioned pumps (service/exchange) if that is the problem? I'm in northern Ireland though so postage could be a problem

but lastly, is it safe to drive on like that? could I do any damage?


edit:

I spoke to the PO's mechanic today and he was able to re-assure me on a few points, mainly that whatever the car needed it got and was indeed well looked after, but it was due a service about now.

I'm leaving it in this week for my mechanic to get a look over it

Hi again bmc,

The temperature gauge should normally be "nailed" to the middle mark (it's not actually connected directly to the temperature sensor like older cars - it's driven from an engine ECU output) . If yours is at three-quarters that is slightly cause for concern as the thermostats can fail after a couple of years so I would definitely fit a new one: you don't say what year your car is but if it's before about mid 2000 then it probably has an engine with Nikasil coated bores (check archives here for affected VIN numbers). That's no problem in itself these days provided the engine does / is not overheating due to a dodgy thermostat.

I would also be worried by dirty coolant - it should be a nice yellow or orange colour depending on the model year - low/no antifreeze can cause severe corrosion in the engine. Please make sure that you, or your mechanic, use the correct special Jaguar antifreeze for the model year. DO NOT use non-Jaguar antifreeze or mix it with other types otherwise various seals can fail.

Regarding your question "is it safe to drive" - I would say definitely not until you get the temperature reading correctly: these engines are easily damaged if they get too hot.

Regarding second hand pumps, you will need to look at the web sites for various breakers e.g. as advertised in the club magazine. I could not find any on offer at the time I rebuilt mine, but you may be lucky.

Regards,

Just to mention try EUORJAGS they are the top ones we recommend for your used pump...........Joe

Thanks for the replies, I noticed the gauge never moves above the 3/4 mark, and coupled with the lack of heat I did suspect the thermostat and will be replacing it during its service tomorrow anyway. I only got the car on Friday night and have done very few miles - although I really want to use it

I also don't know how long the problem has been there. I have been told that the heater water pump is important for the LPG system to work properly so I'm just using petrol at the moment in case I damage it.

Anyway, hopefully a new thermostat, a good flush out and top up with the correct fluids will sort that problem out, although I am not likely to get a pump tomorrow so I will probably just take the car off the road until I get one (just to be on the safe side) and then flush out the system and replace the pump at the same time

next job after that will be the "rattling" catalytic converter.....

oh, and thanks for mentioning eurojags, I used them when I had an XJ40 a few years ago, and forgot about them

Just a quick update..

my eyes have been playing tricks (its a new car and that's my excuse) the temp gauge is in fact dead on centre - I never noticed the way the markings were printed on the gauge. as they start almost a 1/4 of the way up, what I thought (at a glance) was 3/4 was in fact 1/2

I've had the cat fixed, she has now been fully serviced with new filters and oil but my mechanic forgot to do the cooling system so I now am ordering a pump.

tune in late for the next exciting instalment

BMC........ Keep up the story......it may give valuable information....
..Joe

bmc,

Just a thought before you go and buy a new pump: I assume you have already checked the fuse? (they don't normally go, but you never know!)
You can check if the motor brushes have failed quite easily if you have a test meter with fairly thin pin-point probes. If you locate the fuse box at the left hand side of the engine bay and remove fuse no.15 (10A rating) this is solely for the heater pump circuit (Jaguar actually call it "Air Conditioning coolant pump" in the Vehicle Care handbook).

If you pull the fuse out and stick the meter probes in the holes - making sure you are touching the connections - with the meter on a 10A current range or higher, with the ignition on the pump should draw about 3 to 4 amps if running normally, but no current if the brushes are worn out.

Hope that helps -
P.S.
If you did not get the Vehicle Care or any of the other handbooks with your car you may still be able to get them from your Jaguar dealer, otherwise they are on the Jaguar Heritage CD - well worth the £15 quid or so!

For best help you really should state what model / year your car is in you signature line .

Thanks for all the replies, and it was indeed the pump. Reconditioned pump from Eurojag at a cost of £60 + vat & Shipping (total £92) fitted by my local mechanic in 15 minutes Its great to have warm feet again

Hi
If you would like the actual handbooks contact JEC's Andrew Swift.
His contact number is in the list in the magazine, and he may well be able to help. He was able to complete my handbook set.
David

Thanks David, I should have mentioned I have all the handbooks - the last owner kept everything, I still have the original salesman's business card.

Thank you very much for the info re heater pump. Replaced and problem solved.