the highest my temp needle will go is about 1 marked line before the middle line. so it's running a lil on the cold side. is this something to be worried about?

i know it sounds stupid but i just want to make sure im not slowly killing my motor.

oh and this is a completely stock d15

 

If it takes a very long time to warm up and it is running cold (I don't know if it is or not from your discription) you could have a partially stuck open Tstat amoung other things.

Will it hurt your motor? It can if you car doesn't get to the warm cycle. It would be running constantly rich in an attempt to heat up your engine. This will cause your cat to clog and you to have bad gas milage.

If you have plenty of heat pumping out of your vents and/or the temp needle doesn't change between highway and idling at a standstill I would not worry about a stuck Tstat.

Cheers.

 

hot air comes from vents, MPG ~35, temp need stays 1 tick below the middle. so i guess im fine.

also, in the morning when i turn on my car for the first time takes about 10 minutes idling to get to normal operating temp

 

sounds perfect to me.