Having run my 'new' Jag (2.0 l SE diesel estate) for just over a week, I must say I am delighted with it. Drives like a new car even with nearly 100,000 on the clock.

However, I am experiencing one or two little gremlins, and was wondering if anyone had any clues as to what is happening.

The temperature gauge is not working, especially when the car has an electrical load (climate control, lights on etc), and the DSC comes up with an error fault when starting up.

When I first got the car, the headlights were very dim - I thought a tired battery or an alternator fault, but I have had the battery tested (only 65% charged, but testing as OK - now charged up on trickle charge), and the alternator seems to be charging. No starting or cranking problems.

Also, the heater does not seem to be overly hot. It was minus 4 last night, and the heater was at best warm, even when the climate control was turned up to 29 C.

I am not sure if these problems are related, but would welcome a steer on where to look.

Thanks

 

basso, not to ask a silly question, but have you put your hand on the coolant hoses going to the heater core to see if the water going through the hoses is hot. From what I can guess is happening, it sounds like your thermostat is failing and it is maintaining too low of a temp. As a result, what you are seeing is the coolant is remaining too cold (leading to the low coolant gauge reading) and since the coolant is too cool, you are not getting good heat inside the cabin.

The DSC code requires getting the codes read from the plug under the dash. THis will tell you a lot more specific what is going on with the car. Odds are, you are looking at an issue with one of the rear wheel speed sensors (the rings are known to rust and break apart, leading to a loss of wheel speed).

As for the "low power" from the alternator/battery, what I would tell you to do is to connect a multimeter across the battery. With the engine off, it should be reading 12.6 VDC. ANything less than that, your battery is not at 100% charge. Next, start the car as you are watching the multimeter. You should see it jump up to around 14.4 VDC for a few seconds and then slowly lower down to around 13.7 VDC. If you are down around 13.0 VDC, then you have an issue with the alternator or the battery cables are starting to fail on you. If you want to narrow things down more, let me know.

 

Well..... tested the car today. It is cold and frosty, 1 C indicated. Drove the car 30 miles, and the temperature gauge didn't rise from the bottom. The radiator is cold to the touch, and the top hose barely lukewarm.

The fuel consumption on the message centre indicates 38mpg but I suspect it is doing a lot less than that as the fuel gauge is dropping fast, not sure how accurate the message centre is.

Is the only problem likely to be the thermostat, and if so, which one is them most likely suspect?

 

Basso, I would start with the thermostat. It is a fairly easy replacement (atleast on a gas/petrol engine, not sure on the diesel engine) and also is cheap to do if you can do it yourself.

As for the message center, the best advice that I can give you is to get out on a long drive and fill the car up just before leaving and then fill it up again as soon as you get somewhere else. Then look at the distance you travelled, but also compare it to something like Mapquest or GoogleEarth for a distance comparison to ensure you don't have an issue with how the car is calculating distance. Then you can compare your fuel usage to what the car thinks the fuel usage is. If it is off by say 1-2 mpg, then that is pretty good. If it is off by more, may be a sign of other outstanding issues.

 

Car booked in for a check over next week. The weather was a bit warmer yesterday, and I drove the car about 40 miles and the temp gauge rose to about 1/4 after about 20 miles. In freezing weather the car doesn't heat up at all though - is this common with the diesel? I know they are very thermally efficient, but I would expect them to warm up a bit better than luke warm.

 

basso, it is possible that the car does need to have some of the airflow blocked to the radiator to ensure there is enough heat that remains in the coolant to allow the motor to run efficiently. But, at the same time, I would think with the weather that you are having, it would not run as cold as it is. See what the shop says and go from there. But, I am willing to bet that you will find that the thermostat is having issues.

If it is simply that the motor is getting too much cooling, atleast the fix is easy. In the past, I have simply taken a piece of cardboard and covered up half of the radiator to allow more flow through the radiator without the coolant being cooled. Then, in the spring as things start to heat up, you remove the cardboard and call it good. I have contemplated doing that with my car to help with the efficiency since it would allow the thermostat to run a bit more open and reduce the backpressure on the water pump.

 

Diesel engine owners also have to consider the oil cooler thermostat that if U/S also delays warmup. Extract from JTIS refers:

Engine Oil Cooler Thermostat

The engine oil cooler thermostat is located in the water pump housing and helps to reduce the warm-up time by limiting the coolant flow through the lubrication system until the engine reaches its optimum operating temperature. The engine oil cooler thermostat starts to open at 75°C (167°F) and is fully open at 89°C (192°F).

There are many reported instances of this thermostat causing your sort of problem as well as the coolant one!

 

Garage replaced the water thermostat today - made no difference. Oil cooler thermostat on order and in on Thursday, so hopefully that will make the difference....Will report back.

 

OK. Garage has swapped both thermostats - one of them was evidently 'bent'. Car warms up after idling for about 1/2 an hour, but then cools right down when being driven around. Dealer is not happy with this ( to his credit) and has it booked in with another garage with more experience of this marque. Local Jag dealer says it is either the water pump impellers breaking down and not circulating water properly, or there is a small blow in the head gasket causing an air leak into the coolant. I would have thought these would have caused the temperature to go up myself, but if they replace the water pump f.o.c I am not going to complain. Does this make any sense to anyone out there?

 

basso, just because the water temp sensor is not seeing the temp does not mean that the rest of the motor is not baking. Think about a pan on the stove. Where you cook the food is hot, but the handle is still able to be touched with the hand. Same idea with the coolant system of the car. If the water is not being pushed around the block, the cylinders will be getting warm, but the warm water will not make it to the radiator or past the temp sensor.

As for the head gasket leak, I would thing that you would be seeing a lot of bubbling in the overflow bottle and the bottle at a minimum would be getting very warm. In theory, the incoming air can force the water to stop and potentially run backwards. But, again, you should be seeing lots of gases coming out of the overflow bottle if this was happening.

 

OK that make sense. They have tested for head gasket failure, and nothing is showing - thankfully. It is a bit worrying if the parts of the engine have been running over hot though...hope there is no lasting damage....

 

OK. Just got the car back. The garage replaced both thermostats with Jaguar parts - no improvement, and much head scratching and testing, at another garage, ensued.

Turns out the top thermostat replacement was Faulty! New new one put in, and the temp goes up nicely. What a waste of time and money - thankfully not my money, but the dealers (he has been great).

DSC problem showed C1975, dynamic stability control C1165 right rear wheel speed sensor and C1280 Yaw rate sensor. Faults cleared, and now do not show up in message Centre. Road tested and no faults showed. Does this mean that the system is working properly? Bit of a mystery to me why the faults showed in the first place....

 

OK DSC error is still there. Not sure why it only shows up when the car is cold. Garage who did the error codes suggest tackling the speed sensors first, then, I guess, the Yaw control. Do speed sensor errors cause Yaw sensor errors too? Car back to dealer after xmas break......

 

The DSC warning in the circumstances you describe is a common sign of a battery voltage below the DSC system limit. When the car is cold and you crank it, the voltage falls below that limit, but by the time the engine is hot, the battery has been charged sufficiently to cure the problem. You may not be charging the battery enough to keep the voltage high enough when cranking from cold, but more likely, the battery is, unfortunately, past its time and needs replacing.

New batteries solve a lot of Jaguar (and other modern car!) problems!!

 

Thanks for that Astromorg. I had read about this, and it seems to make sense, but I did have the battery and charging system tested and they all showed as good. Is it still possible that the battery is poor after standing over night, but recovers enough to show as good when driven somewhere to be tested?

 

OK. Tested battery charge from standing overnight - reading 12.4v, and the alternator is charging properly. 12.4 is a little low I guess, but when I went to Halfords and they tested the system for me, it was fine, and they refused to sell me a Battery!

 

This is an extract from the Jaguar Battery Care Manual:

Before carrying out an open circuit voltage check, you must
ensure that there is no battery surface charge present.
The battery may be tested either on a bench or on the
vehicle. A vehicle which has had its battery charged or
been driven within 24 hours prior to the test must have its
surface charge removed using one of the following
methods:
– Wait 24 hours before the test is performed.
– Or switch on the headlights on main-beam for
5 minutes for all models except X-TYPE which

should be for 2 minutes only.

Battery O/C voltage should be measured after 10 minutes has elapsed following surface charge removal.

Results obtained:
Open circuit voltage ~ 12.45 volts or less

– Fit replacement battery.
– Scrap or return removed battery.

Unsatisfactory result:

Open circuit voltage ~ 12.45 to 12.49 volts

– Remove and re-charge battery.
– Charge the battery by following the instructions
given with the charger in use (see note on charging
on page 6).
– Carry out a post-charge check (see page 8).
– If the result after charging the battery is 12.49 volts
or less then fit a replacement battery.
– Scrap or return removed battery.

Open circuit voltage ~ 12.5 volts or above

Do one of the following:
– @ Port of entry ~ deliver to the dealership.
– @ Dealership ~ deliver to the customer or put into

storage.

Driving to Halfords would require the 2 min headlight routine followed by a 10 min rest before their test.

 

That is very interesting. Given that my battery at rest is struggling to pull 12.4v I guess that it really isn't sufficient for the X type. I also think that the battery is the original from when the car was new in 2004! I will do a proper test tomorrow, but it looks like I will have to source a decent replacement battery.

Are there any special precautions needed replacing the battery on the X type? I have the radio code....

 

Battery changeover is routine, though depending on how long you take over the change, you may lose the Trip Mileage and average speed and fuel conumption figures so if these are important to you, note them before you start. Finally, don't forget to get a vented battery and connect the breather tube before replacing the battery box lid.