Hi, after a long trip I did an oil change and notice an remnants of an explosion of yellow fluid in the engine bay (see attached photo)
Any ideas as to what it is? The coolant and brake fluid reservoirs are full so I don't think it is that. The car is going fine.
Chris

 

Ooh dear, you have lost your coolant. Very common and very harmful issue. Seen this far too many times, resulting in engine damage. We replace a CX-5 diesel engine about every 2 to 3 weeks.

It's often caused by a faulty radiator cap.

Is your vehicle still under warranty?

I would recommend taking it to Mazda for, Pressure test of the radiator cap, pressure test of the cooling system, carry out a compression test, and vacuum tests.

 

Thanks grim_reaper, very helpful. Yes, even though the coolant reservoir was full, when I checked the radiator itself, it was not. I think the reservoir must have overflowed when we were on a long hot drive (38 degrees celsius outside) and then for some reason did not suck the coolant back into the radiator when it cooled. Would this be due to a faulty radiator cap?
Chris

 

Don't think faulty cap, looks like pressure build up, running too hot, possible head gasket?

 

As mentioned previously, radiator cap failure is common. Get the cap pressure tested.