The coolant temperature gauge on our x-Type 2.2D Auto appears to move around a great deal; it even drops on the overrun going downhill! The engine appears to take an age to warm up (perhaps 6 miles) and the needle usually rests around 3/8 across, only moving up to 1/2 (vertical, midway between blue and red) at 70 mph or so. Fuel consumption is not too impressive, 40 mpg only being possible at a very steady 50-60 mph. Is this behavior normal or do we have a thermostat problem? I'm keen to decide before the car's Jaguar warranty expires in January!

 

Redcat09,
It does sound like your thermostat is stuck in the open position which could account for the symptoms you describe.
Check your car's warranty and if covered get it booked in and done. Though not familiar with your car I would imagine it would still be a straight forward job to do yourself if needs be.

Hope you get sorted,

 

I have a similar problem on my 05 estate. Takes ages to warm up and only gets to about 2/8 unless I'm in heavy traffic. Oddly enough this problem only happened aftre a servuce .

Sorry for the daft question : but are we talking about a thermostatic valve in the cooling pipes here ? If so - where might I find it (or how might I describe to a mechanic what I want checking / replacing ?

 

I'd say thermostat for sure, classic symptoms.......perhaps Temp coolant sensor may also have a part to play.

Neither should be overly expensive

 

Thanks for the replies guys. It would be good if somebody somewhere could confirm that 'yes the needle should be almost rock steady on the x-Type Diesel' like just about every other car I have ever owned.

@JimHunt100 - yes since almost the beginning of time (well almost) internal combustion engines have had a thermostat in the coolant flow that diverts between the radiator and simple re-cycling back to the block to aid warm-up (and it appears, probably to steady the engine temperature at any time, any load alongside the thermostatic radiator fan). It's usually inside the top-hose joint to the cylinder head but i have no idea on this engine (and btw it should not fail at just 25k miles! )

 

@Redcat09

My X-type temp gauge always used to be rock steady - just a whisker below the half-way mark and it NEVER wavered. That was before my 'service;' now it barely gets above 1/4 and takes an age to warm-up. Going to get my thermostat replaced I think !

 

have only just bought my Jag X type diesel (2004 2.0l estate). It is back with the dealer with temp problems as we speak. In the cold weather we have been having in the UK, the temperature gauge never climbs off the bottom stop! They have replaced the thermostat in the water system - problem is still there. They are waiting for delivery of the thermostat on the Oil cooler, which according to many on this site is the one most likely to cause problems. Have others had this problem too.....Watch this space, and let us know how you get on Redcat

 

Well. Got my water thermostat replaced and now the engine temp is steady at about 1/4. Not the usual 1/2 way mark I had before, but some improvement.

I'm now wondering if it is the oil cooler thermostat that is the problem !

 

I've an '06 2.2 d saloon. I've a 15mile commute to work. In summer it takes about 2-3 miles to warm up, but on a winters day it's not at the halfway mark by the time I get home. 12 miles of my journey is on the motorway.

Hope that helps a bit.

 

OK. Oil thermostat replaced, problem still occured. It now turns out that the new top thermostat from Jaguar was faulty! Replaced, and the car now heats up nicely as it should. It just shows you that you shouldn't take anything for granted.

 

Looking at this and the other comments on this thread makes me think that this problem could actually be quite widespread and due to poor quality components. Perhaps many people just don't notice it or bother to get it corrected, putting up with poor fuel economy etc, hardly wise in these straightened times. Anyway ours is going in next week for Jag dealer to comment.

 

Sorry for a daft question(s) but by 'top thermostat' do you mean the coolant thermostat ?

Am I also correct in believing that the 2.0 X-Type Diesel has two thermostats - one for coolant and one for oil ?

If that's the case - then maybe I need to get my oil thermostat replaced as well in order to get the problem finally resolved ?

thanks again for the replies and information - very useful !
Jim

 

Yes Jim, the coolant thermostat is the 'Top' one - oil thermo is down the front of the engine evidently and commonly causes problems. My car now heats up to just under half now - was right on the bottom all the time before.

 

Well that's interesting; my local jaguar dealer confirms that the Diesel engine does indeed take a long time to warm up, the variable reading is quite common, but all is well as long as the interior heater works (which it does). Ho hum; I must say that owning a Jaguar after a lifetime of German cars is proving an interesting experience to say the least!

 

The slower warm up time for modern diesels is common - the Rover 75 diesel is very slow to warm up too and that is a BMW engine. This is because modern diesels are very Thermally efficient evidently. After my Thermostat was changed, the engine warms up after about 5 miles, which is normal - it wasn't warming up at all before...

 

For what it's worth our Jag was recently serviced, during which I insisted that they did not overfill the oil as before (being worried about the life of my DPF). As a result the oil level is now half way between the dipstick marks and guess what? The engine warms up much faster and has a more stable water temperature. Not perfect or rock-steady but certainly better. So perhaps the oil thermostats are ropey as suggested above and a partial cure is less oil sloshing about (no bad thing anyway as the handbook clearly states that an overfill risks a blocked DPF). 'hope this helps someone!