theandies

I don't have any overheating problems and my cooling system only has about 2000 miles on all new parts. I was just wondering what advantage does drilling the small holes in the thermostat gain me. I have seen here that cars with overheating problems, this is a suggestion that comes up from time to time. If I do it, what size holes and how many.
Thanks
John

jerryp58

I don't have any overheating problems
Should I drill my Thermostat???

I would think NO.
I thought the only advantage to the holes was to allow flow even when the thermostat is closed.
I guess that might let you run cooler if you were having cooling problems; but it also might slow down how quickly you reach operating temperature.

Just my $0.02


[Modified by jerryp58, 1:14 PM 3/16/2003]

ram82fire

The real advantage to drilling a hole in the thermostat is realized when filling the engine with coolant . It puts an end to the trapped air problem to a large degree . I know of numerous cases where some real serious temps were spiked when starting new engines .

Geo :thumbs:

SanDiegoPaul

It puts an end to the trapped air problem to a large degree . I know of numerous cases where some real serious temps were spiked when starting new engines .

:iagree:

I had to do that just last week when starting a BB in a '72 we had in the shop. It started to O'heat while we were breaking in the cam. :nono:

WESCH

Hi
By drilling the holes , you can eliminate the bypass water hose from the thermostat to the water pump.
This bypass water is going uncooled back into the engine. Now, the thermostat holes are bypassing this through the radiator, hence 100 % of the water will be cooled.
Again, a bit slower warm up of the engine, but who has a problem with that ?
For the trapped air, all thermostats should ( do ) have a small hole anyway to eliminate this, don't they ?
Rgds Gunther :seeya

Sigforty

I have holes drilled in my stat, but that is because i have a Stewart stage 2 pump. They have no internal bypass so you need to have holes in the thermostat.

Racer16k

To remove trapped air, one 3/16" hole is fine.

d&d74BBcherryred

Our thermostat came with 2 holes but the mechanic told us to drill at least 1 more hole for safety. At least if the thermostat gets stuck shut you will still have some water flow. And yes it deffinately helps with trapped air when changing fluid. Our 454 runs at 200 most of the time now. Before it ran 225 and i was always affraid of the therostat sticking shut. Not now!! :thumbs:

theandies

Thanks everyone. I guess I am going to do it but only one 3/16th inch hole.
John