i just bought a used 86 prelude. it has 160000 miles. but i don't know the guy change timing belt yet or not. is anyway that i can know it from driving the car or i have to open the belt cover to see it? and when i see it, what is the difference between bad or good? thanks

 

You need to look at it. If the belt is cracked, frayed or the teeth on the belt look in any way beat up or broken, replace it. While you're in there, whether you replace the belt or not, be sure to re-tension it.

 

where is the timing belt exactly? is in side the cam gear cover?

 

yes.

 

remove the valve cover. the cam gears and timing belt will be on the front of the motor, right side if you're looking directly into the engine bay from the front of the car.

you'll be able to properly inspect the belt with only the removal of the valve cover.