Thank you very much for the update, very much appreciated. Just to confirm, some time ago I needed to replace the temp sensor and when doing so the little cup shield was so brittle that it broke to pieces so i fitted the new sensor which i had to cut the two wires from the harness and just connected them together and did not weld them and without a shield, all was ok for over three months until timing chain needed replacement which was done by a mechanic, 3 weeks later the problem of overheating started with exactly the same symptoms you described, the gauge goes up to almost three marks above 210 when running the drops back to almost normal but when idle or in traffic with or without AC on it hardly goes one mark max above 210 and drops again. Noticed also when it goes above by one mark i stopped few times and felt the lower hose and it felt warm rather than hot. Guess i will fit a new heat shield for the sensor and solder the connection and see how it goes
many thanks again sir

I see.

Yeah they put that heat shield on for a reason. Mine hasn't gone fallen apart, but it doesn't appear to be shielding the temp sensor from the heat. That is a really hot location for a sensor to live, and a dumb location considering the proximity to the exhaust manifold.

I'm curious of your result when you finish!

Yes, this is where brilliant engineering fails, but what does not make sense to me is that when temp is above 210 on gauge, it only takes 5 seconds of revving engine at around 1500 rpm and gauge falls to 201 instantly !!, the temp of exhaust manifold cannot cool that quick to drop the gauge temp besides the manifold case has nothing to do with revving engine to cool down, logically on the contrary it should raise the temp !!!

Revving it probably cools it a bit by moving a bunch of extra coolant past the sensor without the extra heat from being under a load at 1,500RPM.