Hi everybody. I just had my car serviced and the mechanic told me that there was a slight problem to the "bottle cap" as shown in the image attached.

He told me that there's a small hole which leaks very small amounts of engine coolant, but he told me that this needs my attention and that cap needs to be replaced as soon as possible.

As I'm still in France, there are some significant language barriers and getting parts for the Jags is without a doubt an uphill battle.

So, question: what's the name or perhaps even part no of the part shown in the attached image? It's not part of the engine coolant overflow tank (I think). It looks like a cap of sorts but it's not the high pressure cap of the engine coolant overflow tank. Any pointers would be greatly appreciated.

BTW. My car is a 1998 Jaguar XJ8

Cheers!

 

Its the cap ontop of the thermostat housing that you remove when filling with coolant to let trapped air out

 

Thanks for your reply. In your opinion, is it possible for that cap to leak small amounts of engine coolant? I may have overfilled it a little after getting a Low Engine Coolant message on the dashboard.

 

The cap is more likely to seize than leak but the whole plastic Thermostat Housing is a known weakness. If there's a leak in that area, replacing the assembly is the best option.



Aluminium aftermarket versions are a favourite replacement.

Graham