Yeah, mine did that too. Looking at:
Thermoswitch B "...has authority to switch one of the fans, after the engine has been turned off." Thermoswitch B is very close to the gauge temp sender, and both sit very high on the engine. I think that when the coolant level gets too low, both of these are surrounded by air, not coolant. Very hot air. As a result, the gauge spikes up and the radiator fan runs on.

Does the gauge drop if the engine is revved to a high idle, 2000 rpm or higher?

 

Thanks so much for the link, that's REALLY helpful and useful information

Well, yes it does drop a bit if I rev the engine.

But the funny and strange thing is, it overheats Randomly and whenever it overheats both upper and lower hoses are HOT as HELL!!!

Hate to sound like a broken record, but today in the morning drove it for nearly 1hr and no SIGN of overheating.

You might laugh at me, while driving one of my focus is road and other temp gauge

What else you/anyone else suggest?

 

From my experience, if you turn on the heater full blast like that, it pulls the heat away from the engine causing the car to not overheat. That is how I would prevent mine from overheating in stop and go traffic. I think that is totally normal. With everything you have done already, I am stumped too. Hopefully one of the many guys on here who are smarter than me can give some help...

 

Don't thank me, thank Jim Blake for his excellent post.

I think the randomness is related to coolant level. When the system is filled up and burped then there's no problem at any speed. When the coolant level drops, at higher rev's the water pump volume is high enough to bathe the temp sender and thermoswitch B in coolant, even with low coolant. But water pump volume drops at idle and those sender/switches are surrounded by hot air due to low coolant. Filling and burping the system fixes the problem temporarily.

Find out where your coolant is going.

 

So I tried shorting both the switches today with a copper wire.

When I shorted Thermostat assembly sensor and turned the ignition switch to position II, both Fans came.

Did the same for upper radiator hose and right/passenger one came.

BTW, I drove the car for nearly 3 hrs today, on the highway driving at 60-70 MPH, no overheating, but as soon as I stopped at a traffic light gauge started to climb past the half mark

I have replaced so far heater core hose going below the distributor, upper/lower radiator hoses and various other small hoses.

What other hoses/places or spots I can check and validate for any coolant leaks? Because I do not see any dripping or visible symptoms of coolant leak.

Would appreciate any help, advice and cooperation

 

No external leakage with the pressure tester pumped up, other than the occasional drip from the water pump weep hole?

 

This thread is getting long, and there are a few basic questions I have.

When the car overheats, do you need to add coolant to the radiator when the engine cools down?

Is normal operating temperature on the gauge at the 1/2 mark? Or is it at about 1/4 mark?

Will the fans turn on almost immediately when you shut off the car, but the fans were not running when the car was just idling?

 

Yes, that's right.

Another thing is, coolant is pushed to coolant reservoir, while I always fill the reservoir between Max and Min marks. I filled the radiator and left the coolant level between Min/Max yesterday. When I opened the reservoir today it's nearly full so I pour it back into the radiator and then again left at little over Min mark

 

Thanks so much for helping me out, I am also getting really frustrated and annoyed with this intermittent overheating, can't tell you my frustration

Not daily/everyday though, but DEFINITELY yes, I have to add lil bit coolant or pour back from the reservoir back to the radiator.

Normal operating temperature is always less than 1/2, say between 1/4 and 1/2 or sometimes 1/4.

If the gauge is climbing past the 1/2 mark(~3/4), Fans do come before shutting off the car and one fan continue to run for sometime after shutting off the car.

Thanks again to everyone for all the help and cooperation, please ask if any more questions

 

You have an internal leak. A leakdown test would verify.