99 V6 accord. I see green reminisce of leaked radiator fluid that appears to have came on the side of housing that is near some type of EGR device (if you are looking at Tstat house from the drivers side fender it is on the left). The greed build up is not much at all and older and dried up. At 118k miles how often would that gasket on the Tstat housing be an issue on these cars?

 

my 2000 v6 tstat housing was also leaking. I tightened the nuts to 104 in/lbs of torque and it stopped. If it still leaks, a gasket is $3.00.

 

If you plan on keeping the car for a while it might be best to buy all the hoses, gaskets, and sensors at the same time and swap it all out in one bang.