new problem for my favorite car... I've noticed that about once a week, or a day or two less some times, the engine coolant low notification pops up. after a short drive, I parked and saw a little drip at the front left corner of the car. I followed it to an overflow reservoir there. I bought a new filler cap, but same thing.. what could be causing the pressure in the coolant system to pressurize to the point that the cap is opening and allowing fluid to flow out of that opening?

Jon
2000 XJ8L 130K miles

 

The reservoir itself could be cracked or the hoses/clamps to it could have failed.

Are the hoses to the upper reservoir crossed like this? If not, that could cause problem you describe.
Vector

 

I'll check the hoses in the morning, that would be awesome if that's all that is wrong, I installed backwards!!

Jon

 

It's a common mistake because they don't look correct the way they are supposed to be installed.
Vector

 

ok, had a chance to look on my lunch break. mine doesn't quite look like that. one hose comes from the outer edge (closer to the fender) and doesn't have that disconnect fitting. maybe replaced with aftermarket. it's just a regular hose. and it doesn't head behind the motor as in your picture. it just goes straight to the top of the radiator, left side top. the other hose, closer to the engine on the reservoir, makes that left turn and goes along the fender to the tank under that headlight assembly(overflow).

Jon

 

About 9 times out of 10 if you are not paying attention, or taking pics, this connection is re-installed wrong and causes the symptoms you describe. Since the connections have been replaced I would say there is a very high likelihood that this is the case.

I will try to find and post a complete routing pic or diagram for the hoses, but I bet you have found your problem.
Alden

 

I can't tell from your description if it is routed correctly, see diagram.

Also check post #4 in this thread for a descrition of where the hoses should go: https://www.jaguarforums.com/forum/x...fitting-65174/

Vector

 

He has a supercharged model. On standard non supercharger models one of the pipes goes straight to the radiator (90°, 90° straight, 90°, 90°). The other pipe leads to the fender/wing and disappears under the ABS unit front left. The last pipe (sits on the side of the water bottle) goes to the thermostattower.

Part number 7 leads to the radiator.
Part number 6 leads to the thermostattower.
Part number 4 to the atmospheric water bottle.

Correct seating can be seen here:

And here is the correct order:



They are the standard non super charged model connections!!!

 

Right, V has a SC model; D (op) is non supercharged and from his description appears he is plumbed correctly. What is noteworthy, however, is his comment that the pipe going to the radiator is not the conventional plastic pipe. Given where the leak is, left front, I am betting that it is leaking at the nipple at the radiator.

Maybe, it is time to invest in a part number seven on the diagram. About $46 US.