Civic EG

is there a differance in the thermostat in between OEM and aftermarket
a mech. told me that i should use a oem one instead somthing to do with the springs of some sort.....

I say OEM FTW

oem quality is almost always the best

I've always used parts store aftermarket. Thermostat is not that critical and it's likely that the OEM uses an aftermarket company to make them as well.

Compare the prices and decide for yourself.

Ive used both on Honda's and always used parts store brands on other makes. Never had any issues. You have to remember, ther are just some parts that car makers use the same parts store brands and relabel them to up the price.

For instance, Stant brand has been making T-stats, Rad caps, and gas caps for as long as I can remember. Never heard anything bad.

you can use oem or aftermarket, just make sure the temp spec are the same

nd when i mean temp spec, for instance if your car has a 180* thermostat
dont put a 220* theromostat in or a 150* thermostat