My car believes it is low on coolant despite having filling it up weeks ago. I am now receiving a message of "restricted performance". I believe my coolant thermometer sensor is faulty, so I have purchased a new one. Now my problem is that I don't know where this part is located. On other Jaguar models, it appeared more noticeably. Does anyone know where this sensor is located on a 2000 vanden plas by chance?

 

It is plugged into the bottom of the coolant reservoir. You will probably break the old one getting it out without removing the reservoir but stand a reasonable chance of getting the new one in ok.

Personally, I would remove the reservoir so you can see what you are doing. I have replaced a couple and they simply snap into place but the last new reservoir I installed had the sensor firmly glued in place.

The magnetic float stuck on its tube with old coolant crud is as likely the cause as a defective sensor contact.

[edit] Reread your post. Are we talking about the low coolant sensor or the temperature sensor. Low coolant sensor above.

 

The engine coolant temp sensor is in the plastic outlet pipe on the front/top of the engine.
The level sensor is where TEST POINT said.
Throwing parts at a problem usually does not fix the car.
What codes are logged in the modules?????

bob gauff

 

I'm receiving a message saying "low coolant" and at times "restricted performance". When plugged in, I don't receive any codes. Should I have the fluid flushed/replaced before checking into sensors?

 

Hi
I researched these 2 Sensors in the JTIS21 shop manual and in the JEPC (Jaguar Electronic Parts Catalog).

The Coolant Level Sensor (Fluid Level Sensor) is located under the Coolant Expansion Tank (look at the back of the engine compartment {firewall} on driver side).
Part number is LNA5740AB.




Here is a PDF file I created/extracted from JTIS21 shop repair manual - shows Coolant Expansion Tank R&I (has Coolant Level Sensor removal):

XJ (X308) Coolant Expansion Tank R&I.pdf

Engine Temperture Sensor (Coolant Temperture Sensor) is located in Coolant Outlet Pipe near the Thermostat Tower (look at the front of the engine - next to the top of the Radiator).
Part number is AJ810031 (part number - LRA1600AA is superceded).









Hope this information helps.

Jim Lombardi

 

The two thing are most likely not related.

The coolant level sensors do fail - sometimes they just stick. It is a reed switch controlled by a magnetized float -- make sure that the float is moving and see if it actually "floats" You can replace the sensor without replacing the whole tank. I would recommend that you fix it -- with the amount of hoses and the catastrophic consequences of having a low coolant issue with the aluminum V8 -- you want the sensor to be working.


The restricted performance can be caused by many things - often a bad connection at the T body .... and sometimes no codes ... do a search and check the connections.

 

Hi yeldogt

I do not believe that I said the 2 sensors (coolant level sensor, coolant temperature sensor) were related issues.

What I was trying to establish was to identify the sensor that he purchased and where it would be removed and where the new one would be installed. That is why I listed the part numbers, part descriptions, and where they are located in the engine compartment.

That was my main objective in the detailed posting yesterday.

Jim Lombardi

 

Hi Claugher
I also reread your post - (My car believes it is low on coolant despite having filling it up weeks ago) - does that mean that your coolant expanison tank is actually full now and you are still getting the low coolant message displayed?

If the above is true, then you probably do have a stuck coolant level sensor in the bottom of the coolant expansion tank.

I also that same problem last year. I solved the issue by stirring the coolant in the cooling expansion tank with a long plastic handle spoon (the stirring dislodged the stuck sensor and allowed it to float again).

Try it.

Jim Lombardi

 

Thank you very much everyone. Luckily, this time the problem was indeed the level sensor being stuck. Guess I'll hold on to that temperature sensor in case I have any problems in the future.

 

Jim - my post was not to imply that you suggested anything ... I was just speaking to the original post.

 

I have a question about the ECT sensor... Right now I'm about to change mine because I have problems with cold starts and I believe the problem is related to it (as weather temps are getting lower the first 15-40 seconds of engine work is very rough and when I try to step on acceleration the engine doesn't increase RPM and even sometime it drops under 500 RPM until I step to kickdown - once reaching 2000 RPM everything is mysteriously fixed).

The problem is that my VIN is 836740 and there is no part number for ECT for my car When I check in the Jaguar EPC it says "from 853936" and there is no option before this VIN Any ideas?!! And what does it mean the designation M12 and M18?!

 

hey dude listen your misfiring on your cylinders...i just had the same exact problem i have a base xj8 2000... I changed out my ignition coils no more "restricted performance" it would come on and go off dont let it go to long or its going to be a pain in the rear. They are expensive if you buy them new i was fortunate to find a jag in the junk yard that was just totaled so i got mine cheap but jaguar will charge 127$ each and you have 8 of them i suggest hooking it up to a computer and figure out what is misfiring, no need to change all of them at once...i looked around online and found them for 79$. Also, your thermostat is sticking which is why your getting that code i literally have the same code right now im shopping around trying to find parts to change out my thermostat. Do not let your car warm up to long and also if your running your car hard at all on the eway and your a/c is running you can also build up to much pressure from thermo not working and youll blow off your radiator hose...ive done it to many times lately.

 

You need to fix your oiling problem first because it is fouling your plugs and confusing things.

M12 = 12mm diameter nominal thread, so there must have been two different diameters used depending on VIN.

 

I now - I just wanted to fix all the remaining issues at once... I'm planning a very long trip next month and I want to be prepared for a 10'000km without any problems. And as I already ordered new set of valve seals and cam cover gaskets I thought it would be great to order new ECT sensor to fix the cold start issue as well

Thanks anyway I'll just remove the old sensor and will check it's size and values that it returns.

RidenXj8 -> I'm not sure if your reply was for me, but I have checked my coils already and at least - I don't have any faults on the ECU, so it's not the case. And the thermostat is also new, so...

 

I have some additional input to this issue. I was doing some other repair, replacing heater pump , and had to remove the coolant expansion tank. I found that the previous owner (or thier shop) had disconnected the level sensor and put a shorting wire in the connector to bypass it. I removed the sensor and found that it was working OK. I found out that the float inside the expansion tank no longer floats so it is always at the bottom of the tank. So the solution in this case is that you have to replace the expansion tank since the float is built into it. I tested this by filling it with water with the sensor in place saw that the float did not float (it was not stuck and does moves smoothly up and down) and when I manually moved the float up by hand the sensor switch closes as it should. (closed = full, open = empty)
Here is a picture of the float that is inside the expansion tank, the dot is the magnet:

 

Mr Lombardi,

I thought it was an excellent description. Thank you.

Tom Vroom

 

Wow: I thought it was bad enough that #15 resurrected a five year old thread, but here you are commenting on one that is nine years old.

 

I don't like to see people kick at the good guys!

Nice work.