Most modern cars are lying to you and doing so directly in front of your eyes -- the gauges ..... particularly the coolant temperature and the oil pressure gauges. Electronic gauges can be programed like anything else -- the coolant temperature gauge in the x308 is programed so that the needle will stay in the center of the gauge over a very wide temperature range. Your Jaguar will tell you all is normal at 180F and still report everything is fine at almost 240F ...when this may or may not be true.


I first discovered the gauge manipulation with my 1995 x300 vdp when it was less than a year old. The oil pressure gauge fell to zero while I was driving. Coming from an earlier Jaguar equipped with an analog pressure gauge and knowing the reliability of analog gauges I stopped driving the car figuring a lost pump or other major failure. When I called my dealer and was told "not to worry about it" I naturally was surprised. I later discovered the gauge was only capable of showing "0" or "normal". The gauge was connected to a simple pressure switch and was really nothing more than an "idiot light" -- it was not a gauge at all.


Unfortunately, the way the gauge is programed in the x308 it will not show you the normal seasonal variables that make gauges so valuable over time. What would be a normal indication on a 100 degree day would cause alarm in the winter ...... driving in traffic vs highway -- all the nuances are lost. This is of particular concern in the early cars equipped with brittle water pump vanes -- I'm sure if the cars were equipped with a true progressive gauge that many owners would have been able to see the unusual increase in coolant temperatures as the pump vans began to fail and loose efficiency.


I have been aware of this -- but all the recent head gasket discussions and a recent post link by 'test point' made me think that many may not understand the operation. It is important to understand that having the temperature gauge move very far above the center line is showing a very high coolant temperature. Another indication is the cooling fans -- they are set to switch to high speed at 207F -- mine are rarely on even in the mid-atlantic summers.

Go to this thread on the XK board where someone has actually tested his gauge at different temperatures. https://www.jaguarforums.com/forum/x...e-gauge-62813/

 

interesting read, thank you

 

Thanks for posting this... I really didn't know about it. And now, after reading your post, I'm pretty sure that the fuel gauge is showing some kind of approximate state as well based on the current fuel consumption, because when I start the engine the needle is pointing to a lower level than it was when turning off, and after driving for a 5-10 minutes, the needle magically goes up... I was wondering why, but now I believe the reason is the same.

 

your fuel level indicator is more than likely a float or sender issue.

Most are not that accurate ... only relative. We rent a lot of cars and it is amazing how inaccurate many are.

My Jag reads empty when it has at least 1/4 of a tank remaining.

 

Some of you may have followed the corresponding link on the XK8/R forum The Folly of the Temperature Gauge. I have just developed an electronic module that converts the factory temperature guage to display the true temperature. I plan to start selling them late next month.

Fortunately for XJ (X308) owners, your car uses the exact same gauge cluster as the XK8/R. I therefore plan to make this module available to you also!

I need an X308 owner who is willing to work with me and test my unit on your car and give me detailed feedback as to performance, installation and documentation. I will need you to install the unit promptly once you receive it. You should be comfortable doing small jobs on your car (installation is not too hard), and own an OBDII reader that can read the coolant temperature so you can check accuracy. If you are near the Washington DC area, all the better, but it is not a requirement.

The reward for your trouble is you get to keep the unit for free (which will probably sell for between $100-$150...the exact price is not set yet).

Post or PM ASAP if interested!! If there is more than one candidate, the others not chosen will get a discount on the product once it is available.

 

My 'Beta tester' has now signed up.

Yeldogt expressed very well the value of this product:

This product might save your engine one day from a slowly degrading condition or a sudden cooling system failure. In addition to displaying the real temperature on the factory gauge, it has an audible alarm (which can be supressed) for severe overtemperature situations. It also has a memory feature which lets you review the max.temperature over the last 60 runs of the car, so you can monitor a potentially slow degrading situation.

If you have interest, please contact me on my website below...this will help me plan for the early demand. The more I can make, the better pricing I can offer.

 

Subbed

 

I indicated my interest on the website

This will be a great product