What is a drilled thermostat?

I am planning to install an aftermarket t-stat, 180* in my 1996 riviera (3800SII).

A drilled t-stat is an option for a $1 more at the store, but do I really need it?

I have head a drilled t-stat will always be open, allowing an uninterruptable supply of coolant to the radiator. Is that true? Because If it is I wouldnt want that. It would take forever to warm the car up in the winter, right?

I have head a drilled t-stat will always be open, allowing an uninterruptable supply of coolant to the radiator. Is that true? Because If it is I wouldnt want that. It would take forever to warm the car up in the winter, right?
Well, that's correct for a thermostat that is stuck open. But a drilled T stat is not quite always open.
It is identical to a normal stat except it has a tiny hole drilled in the metal around the opening, not much bigger than paper clip wire. This allows air to pass through when you are filling the cooling system, making it easier to purge all the air from the engine block when coolant is going in. This eliminates air pockets, localized overheating and 'topping up' of the coolant level after a couple of trips.

This hole is useful, but IMO not worth a buck more. Some intake manifolds have a removable bleeder screw beside the stat housing that can be removed when filling to achieve the same result.

If you have a drill and a tiny drill bit, you can drill your own hole in the cheap stat and save $1.

BTW the hole is too small to allow an appreciable amount of coolant to get through during warm-up.

Hey thanx for making things clearer.

I would, ofcourse drill the t-stat myself, but since I dont know exactly where to drill the hole and what precisely what diameter they make them, Ill buy a drilled one to serve as an example for possible future replacements.

TY

Hey thanx for making things clearer.

I would, ofcourse drill the t-stat myself, but since I dont know exactly where to drill the hole and what precisely what diameter they make them, Ill buy a drilled one to serve as an example for possible future replacements.

TY

The holes should in most cases be installed at about the 12 oclock position.

It may be better to stay with a 190 thermo.
For engine performance and the engine needs the 190 degree heat to burn condensation and sludge out.
Also winter heat.
MT

The hole is usually pointed towards the neck of the thermostat housing (pointing towards radiator or pointing UP. It is usually just a 1/16 noth in the housing allowing air to escape. I have never heard it called "drilled"

Could "driled" be refering to something else (like a restrictor plate) ?

Hey

unfortunately now I have problems finding one on internet to order

so far i have this:

http://rep.racepages.com/parts/racepages/wizard.jsp?year=1996&make=BU&model=RIVI--006&category=G&part=Thermostat&dp=true&showdc=true#top ,

any suggestions?

thank you