So as the title says, my jag was X piped and had its resonators removed, however since then I’ve been having issues with the jag such as it going into restriction mode, having to relieve pressure from the coolant reservoir. My question is the guy who had it done said they had 4 resonators removed, is their actually 4 of them? And also could anyone give me some sorta idea as to why it’s doing what it’s doing? I’d love to be able to go joy riding in the Jaguar but at this point in time I can’t.

 

Also, it’s the XF premium with the 5.0 v8

 

DaltonJ95, welcome to the Forums. Lots of good information here. You may find that you will get a better answer to your question if you post it in the correct section. If you look a little lower on the page with all the sections, you will find an area for your year car. Those people are going to know your car inside out.

As for your issue, I would venture to guess that you also installed a freer flowing muffler at this same time. What can happen is that for emissions, the 5.0L motor requires a certain amount of back pressure. By removing 2 resonators and installing an X-pipe (which has the effect of sucking exhaust gases out the other side of the engine, freeing the piping to flow new exhaust there with less restrictions), you have lowered the back pressure too far, causing the car to see excessive emissions. That will throw codes and lead to random issues.

As for the coolant reservoir being pressurized, that is somewhat normal. Newer cars run the engines right about the point where water boils. So, part of what happens is when the motor is warm, there is a finite amount of steam in the system to help build up a pressure to cause the water to not boil due to the increased pressure. So, if you have just ran the car, yes, you will see pressure in the coolant expansion tank. If the motor is cold and you are seeing pressure, then you need to do some more investigation.

 

We will need the error codes? The car is going in restricted mode so there is a reason it's doing that.

Cooling problems are very common what have you replaced? Water pump is a known failure spot.
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