Jaguar XF Coolant Loss Points to Head Gasket Issue

Had a similar issue with my 2015 Jaguar XE diesel last winter. With some experience working on cars, I initially thought it was a head gasket issue too, but it turned out to be much simpler. After noticing coolant loss and getting similar warning lights, I took it to my regular workshop. They found a loose electrical connection at the coolant level sensor. The faulty connection was causing incorrect readings and triggering the check engine light. Total repair cost was 95€ for diagnostics and fixing the connection. However, your consistent coolant loss sounds more serious than just a sensor issue. Could be several things: A failing water pump, Hidden coolant leak in a hard-to-spot area, Air pockets in the cooling system, Internal leak causing engine overheating Before jumping to conclusions about the head gasket, would need to know: Are you seeing white exhaust smoke? Any sweet smell from the exhaust? Does the engine temperature stay normal? Exact engine size and mileage? This information would help narrow down the possible causes and suggest the best course of action.

Thanks for the helpful suggestions. My engine temperature stays normal and there is no white smoke or sweet smell from the exhaust. Just checked the radiator hoses and they seem fine, no visible leaks or cracks. The car has 85365 KM on the odometer and had its last major service 6 months ago. The radiator cap appears to be sealing properly when checked, but I notice the coolant level drops faster when driving on highways. I will have the water pump inspected since that could explain the gradual coolant loss without visible leaks. Hoping to avoid major engine overheating issues by catching this early.

Thanks for the additional details. Based on your description and my experience with the same issue on my Jaguar XE, the symptoms point strongly toward a failing water pump. The pattern of coolant loss being more noticeable during highway driving matches what I experienced exactly. When my water pump started failing, there were no obvious external signs either. The coolant would disappear gradually, just like in your case. The cooling fan was working properly, but the system was slowly losing pressure. Here is what my repair involved: Complete water pump replacement, New coolant, System pressure test, Bleeding the cooling system Total cost was around 450€ for parts and labor. Worth every cent as it completely resolved the issue. The repair prevented potential engine overheating and more expensive damage down the line. Since your mileage is similar to what mine was when the pump failed, and given the identical symptoms, I would suggest getting the water pump checked as soon as possible. Waiting too long could lead to complete pump failure and potential engine damage.

Thanks for the detailed explanation. Your similar experience with a failing water pump really helps me understand what I might be dealing with. The fact that your repair resolved the issue gives me confidence that I am on the right track. I will book an appointment with a workshop tomorrow to have the water pump inspected. The cost of 450€ sounds reasonable compared to the potential damage that could occur if I let the coolant reservoir keep running low. I checked all radiator hoses again today and noticed the coolant level in the reservoir dropped another few millimeters since yesterday. Engine still running at normal temperature though, and the cooling fan seems to be working fine. Will keep monitoring closely until I can get it checked out. Let me know if you remember any specific warning signs I should watch for before the water pump failed completely. I am trying to avoid getting stranded on my regular highway commute.