I have a question what it cause if the servo overheating with 2S battery?

Most probably nothing to do with 2S battery since your ESC has some sort of built in BEC which regulates the supply voltage to the receiver, usually 6V typical

If you are doing a lot of sawing action with your steering or the servo isnt rated for the application, the motor inside the servo will easily heat up and possibly overheat. Seeing you are running a stadium truck, the servo might not have enough torque and being overloaded. In that case you might want to upgrade to a servo to something with a higher torque rating and/ with a metal body for better heat dissipation

I would also check all your steering linkages just to make sure everything is moving freely and not causing the overheating issue

Is it the servo body itself or is it the servo wire that's getting hot? I'd check to make sure the steering rack moves freely. Disconnect the steering link from the rack and see if it is bound anywhere. It doesn't take much, even half a turn on a bolt in your steering rack can make a huge difference.

I noticed your sig mentions the Orion R10.1 esc, if that's what you are using in the particular car you're having issues with I think you can rule out sending too high of voltage to he servo since that esc uses a 6V BEC.

My servo is Blue Bird BLS-46A and ESC orion r10.1
Specification:
Torque @6V 32.9 KG-CM/456.9 0Z
Torque @ 7.4 421.1 KG-CM/ 584.08 oz
Torque @ 8.4 47.5 KG-CM/659.8 oz

I am assuming have a lot of torque after a few minutes running it stop and the temperature of the servo is 140's but the ESC still running. Also removed the steering linkage is very loose not tight. After turn off the ESC servo it works again.

Well that servo most certainly have enough torque to deal with most situation. Not really sure why it would go into overheat protection.

Maybe you need to take it up to the manufacture

no blocking endpoints?

Nope i also removed from truck and test again after less than minute reach temp @ 114 deg.

Is 114 bad?

I bet my servo gets much hotter, especially when ambient is 115.

Well i am worried in amain maybe gonna blow up. Didn't race yet just test on my driveway but seems too hot for me

Seems like it's just fine to me. Quit worrying about it and run it at the track first. There it'll also have some air flow over it.

He did mention the servo stopped running after a few mins and reaching temps of 140