Drilling 1 T-stat hole or a few?
 

Before a new t-stat is dropped in, is it better to drill one correct size hole or a few ? Also should the hole be situated "north, south, east or west", when looking at the engine from the front or does it even matter?

I was thinking of only one hole in my 180 t-stat just to prevent air being lcoked in the cooling system at first. Also, with one hole will the engine really take all that much longer to get to operating temps? And if about so how much longer?

So if I understand correctly: if there were a few holes drilled it would serve to still keep a small but constant flow of coolant through the stat while also getting rid of trapped air; but one hole would basically really serve only to help trapped air escape from the cooling system?

I started with two 1/16" holes 180 degrees apart in my 180 Thermostat. 8)
you can go as high as four holes, but I would recommend against this for starting, as you can always drill more holes, but you can't fill them in though.

I learned the hard way. The holes don't need to be very big. Depending on your climate, either 2 or 4 1/16" holes. Make sure the holes are far enough inboard that the little rubber seal doesn't cover them. De-burr after drilling, and rinse well. You don't want the metal particles in your cooling system.

I drilled 4 - 1/16" holes in mine and regret it because it takes a full 15 minutes to warm up and that is killing my fuel mileage around town for those 10 min trips.
In the cooler months (45 F and less) it even sets off the SES light with an "engine failing to reach operating temp" warning for those 10 min trips.
When the engine is in warm up mode I average 15 mpg but once warm it goes up to above 20 mpg.
I have another 180 stat ready to go in around October. I will only drill one very small hole in that one, maybe none at all.

We drilled 3 1/16" holes in the 160 t-stat we put in the GTP. It takes 10 minutes tops to warm up, and once it gets warmed up it runs a toasty 165 degrees all the time, winter or summer, and at the track we use the fan switch and keep it at 155 degrees, that is where all the power is made. I would not drill more than 3 holes, as it is very unnecessary, and even 3 holes will probably set the SES light, but its disabled in the GTP so it doesn't matter. We drilled 2 in the SSEi's 180, and it works plenty good, we only have 3 in the GTP because it isn't driven in the Winter (except for VERY rare occasions) so we don't care how long it takes to warm up. The SSEi is driven all year round, but I think 2 holes would be too much if it didn't have those nice seat heaters. Anyways, drill 2 or three holes and it should be plenty, more than that and you aren't gonna be happy.

I think alot of this is climate dependent. I live in a relatively mild climate compared to some of you. My car never takes more than 7 or 8 minutes to warm up, even in the winter with 4 holes. I run a consistent 190° winter or summer.