Just bought a 2012 LR with 5.0. These codes showed up P0128 P003C and it’s overheating. Changed the oil and the P003C and red triangle went away. Now I need to deal with the overheating, seems like the P0128 is the thermostat, looking to order one it seems there are metal and plastic from Atlantic British which one is recommended or from where? Now have only yellow triangle, would the overheating also throw more codes, I feel it needs to bleed the air. It did need coolant when I got it, it sounds ok although I never owned a lr4.

 

If the coolant crossover pipes have not been replaced, you should probably do those, the thermostat, and the water pump.

 

Where or link for water pump, thermostat, crossover or maybe brand for parts.

 

many folks buy these from atlantic british. they stock both JLR and oems for a lot of items. FCP Euro may have what you need as well. I would steer clear of the ebay and amazon stuff as you really want oe for the cooling system parts on these vehicles.

 

if it is already overheating and you do not have a leak and you are sure coolant is full with no air pockets, i would check coolant for combustion gasses before i replaced all of that stuff just to be sure you dont have a head and/or head gasket issue.

 

Thanks for the answers to my questions. Will do the head gasket test, although I already ordered the water pump and thermostat. It looks like it’s leaking from the water pump, used some coolant dye. Today I will look for more leaks.

 

Best do a pressure test. You won't be able to see all the possible leaking points.
Cheers