The Oldsmobile Connection

destineal · Joined: 08 Sep 2007 Posts: 86

Hey guys, I got a 180ᵒ thermostat and i need to know does it matter where i drill a hole and what size hole? 1/16? 1/8?

destineal · Joined: 08 Sep 2007 Posts: 86

I chose a 3/32 drill bit. Does the hole look big enough, or should I go up to 1/8? Should I add another hole on the other side?

73Delta88 · Posted: Sun Oct 28, 2007 11:57 pm Post subject: Re: 180* Thermostat drilling

I'm just curious, why do you drill a thermostat? I've never done it, and never had a problem.

I'm guessing so air will escape faster and you won't have to wait till the engine comes up to operating temperature to completely fill the system when initially filling it.... which only takes 5 minutes anyway :lol:

I can't imagine it would have any cooling effect under normal conditions. or does it?

destineal · Joined: 08 Sep 2007 Posts: 86

Why Drill Holes in your Thermostat?

Why Drill Holes in Your Thermostat?
I guess the obvious reason is to keep your car cooler therefore controlling KR. However the holes only reduce overall engine temps by about 5 degrees so we have a much more important reason for this.

While at the track you open the hood, maybe ice the charger and let the motor cool down between runs. This may bring your coolant temps down to very low levels, which is good however these cool temps may actually slow you down. With the coolant and engine cooled down there is no coolant circulating until the engine temps reach the temp of the Thermostat.

This would normally be OK however when you're racing the combustion chambers heat up very quickly. So the coolant around the cylinders and heads might reach 250 degrees before the stat even begins to open. This is very bad and can cause high levels of KR in the back half of the ¼ mile. By drilling the holes in the thermostat you can eliminate this problem because you will always have a small amount of coolant flowing.

"Performance blasting down the ¼ mile isn’t the only advantage of having holes drilled in your thermostat. If you live in a colder climate this $11 investment might just save your cylinder heads from being cracked and damaged from the sudden dive in coolant temperature as your winter chilled radiator dumps it’s freezing coolant through your heads.

A drilled stat would be much more forgiving by providing a continuous flow of coolant and reducing sudden and drastic temperature changes."
- Andy H
Duluth, MN
1999 Grand Prix GTP
02/16/2004

73Delta88 · Posted: Mon Oct 29, 2007 8:00 am Post subject: Re: 180* Thermostat drilling

hmm, all through a 3/32" hole huh :confused:

guess I don't need to worry about that since I don't race my car or "ice down my charger" :lol:

andrewk · Joined: 18 May 2005 Posts: 1263 Location: Ames, IA

This is a placebo-

Simplest way I can say this: None of this is even remotely true.

A 180 degree thermostat opens when it reaches 180 degrees. Your coolant temps in the engine won't be north of 250, they will be 180-185.

Your heads are not going to be cracked from the "sudden change" of coolant temp. If it were a problem, GM would have discovered in during their R&D, and if they hadn't it would be a wide spread problem, as 60 percent of this country has a cold winter.

Go ahead and do it if it makes you feel better, but you would be better off buying beer with that 11 bucks... JMO

Andrew

73Delta88 · Posted: Mon Oct 29, 2007 9:52 am Post subject: Re: 180* Thermostat drilling

andrewk wrote: A 180 degree thermostat opens when it reaches 180 degrees. Your coolant temps in the engine won't be north of 250, they will be 180-185.

And I would think there is some "gray area" for the thermostat being completely open or closed, it doesn't suddenly just snap all the way open once the temperature gets to 180 degrees and snap all the way closed once it gets down to 179 :lol:

destineal · Joined: 08 Sep 2007 Posts: 86

well its got a hole in it now. Didn't know what size to do so i chose 3/32

OldsGuy · Joined: 16 Feb 2004 Posts: 269 Location: Lees Summit MO

All Oldsmobile V8's that I know of have the "bypass" function, you know, that little hose (some engines have an actual rigid tube which is part of the t'stat housing) that routes to the top of the water pump. So drilling the t'stat is a moot point.

88 Coupe · Posted: Wed Oct 31, 2007 1:38 am Post subject: Re: 180* Thermostat drilling

destineal wrote: ........ what size hole? 1/16? 1/8?
Depends who is passing out the advice.

From the following:
http://www.oldsconnection.com/forum/viewtopic.php?p=10563#10563

88 Coupe wrote: Hans wrote: ........ drilled is not a bad thing to do either, do 2 1/16th diam holes as well ..........
Please explain.
He was unable to.

destineal wrote: ........ I guess the obvious reason is to keep your car cooler therefore controlling KR ........
Do you have a KR problem?

destineal wrote: ........ the holes only reduce overall engine temps by about 5 degrees ........
Maybe someone can tell us how a couple of ⅛" holes could cause any reduction, at all.

destineal wrote: ........ While at the track you open the hood, maybe ice the charger and let the motor cool down between runs ........
Do you do this on the street, while waiting for the light to change?

destineal wrote: ........ With the coolant and engine cooled down there is no coolant circulating until the engine temps reach the temp of the Thermostat ........
Not true. Seems the author is not aware of the bypass system that is already designed into the cooling system.

destineal wrote: ........ - Andy H
Duluth, MN
1999 Grand Prix GTP
02/16/2004
Who is this guy, and what are his credentials?

Norm

88 Coupe · Posted: Wed Oct 31, 2007 2:06 am Post subject: Re: 180* Thermostat drilling

73Delta88 wrote: ........ I'm guessing so air will escape faster ........
Exactly. Stats for some applications, come with holes for that purpose.

73Delta88 wrote: ........ it doesn't suddenly just snap all the way open .......
It should be fully open, at its rated temp, and partially close if the temp drops below it. The idea is to maintain that temp. No more, no less.

Norm

88 Coupe · Posted: Wed Oct 31, 2007 3:08 am Post subject: Re: 180* Thermostat drilling

destineal wrote: well its got a hole in it now. Didn't know what size to do so i chose 3/32
Beer would have been a better investment, but your hole won't hurt a thing.

Using a 180° stat in place of a 195° would be a different subject.

OldsGuy wrote: All Oldsmobile V8's that I know of have the "bypass" function ........
All liquid cooled engines (including his V6) that use thermostats have the same (or a similar) feature. Some do it externally, some do it internally.

Norm

afrats · Joined: 13 Mar 2007 Posts: 84 Location: Colorado Springs

Does it really matter anyway? You drive a 1994 Olds 98 Regency. So do I and if I toook my car to the track they would ask when my grandpa wants his car back. Don't get me wrong, I love my Olds. But it is not meant for the track, it is more for cruising.

destineal · Joined: 08 Sep 2007 Posts: 86

never been to the track. I'm basically attempting to customize my car to make it unique in a sense. Besides, I've only seen grandma's driving 98s anyway :blush:

Looks like we have the same Short Ram intake under the hood sucking in everything except cold air. Ebay?

destineal · Joined: 08 Sep 2007 Posts: 86

88 Coupe wrote: destineal wrote: well its got a hole in it now. Didn't know what size to do so i chose 3/32
Beer would have been a better investment, but your hole won't hurt a thing.

Using a 180° stat in place of a 195° would be a different subject.
Norm

Not a big beer fan but I did manage to get a 180* tstat. jus gotta install it.