I live in the gulf area, in UAE where it's too hot in summer, I bought a car imported from Japan, not to Gulf specification, well in winter time, all is fine, when summer comes, and it's too hot, the Temp will rise up to 105C, which is too much I guess, I tried every thing to fix this problem, change the radiator, change the clutch of the auxiliary fan, change pipes, using the best coolant, ...etc..

but still, when I'm not moving the car on a high way, or driving slow, the temp will go up to 105 as i mentioned, and will reach 95 If I'm driving fast, some told me that on the exhaust there is something like a filter, they use it in cold countries, as Germany, or Japan, smthg like chock, to overheat the car, 2 peaces are inside the engine room, and other is at the exhaust pipe, and I need to remove them, I don't find that correct, and don't want to start cutting amd welding in the car, what else can I do, so many mechanics c the car, non could give me a good answer.. plz advise me