[Formulas]

Funny how a few years ago drilling holes in thermostats was frowned upon on this site.

Seems to be more common now

It DOES keep you from having an air pocket on fill and it does stabilize temps a little more closer to rated temp decreasing spikes and shortening them

Only downside ( could ) be on sub zero days and really the old Pontiac should be in the garage, I know one someone will say i drive all year good for you it doesn't mean the modification doesn't work

[padgett]

Just leaving out has always been bad, 3/4" hole is good to prevent cavitation. Small hole in a good stat (I like Stant Superstats) won't hurt.

[ZeGermanHam]

I don't know why anyone would frown upon drilling a small hole in a t-stat. It's not uncommon for newer cars to come with t-stats from the factory that have small vent holes in them. That's why they often have an orientation arrow on them.

[Tom Vaught]

Originally Posted by Formulas

Funny how a few years ago drilling holes in thermostats was frowned upon on this site.

Seems to be more common now

It DOES keep you from having an air pocket on fill and it does stabilize temps a little more closer to rated temp decreasing spikes and shortening them

Only downside ( could ) be on sub zero days and really the old Pontiac should be in the garage, I know one someone will say i drive all year good for you it doesn't mean the modification doesn't work

I wonder why.

I brought the GTO to Michigan in 1971. Delbert, the World War II Mechanic was working on the floor. He knew I had come from Missouri. And the car had been parked inside a barn during the winters there.

So I had developed a Heater Core leak. So he showed me how to remove the Heater box assy under the hood, remove the heater core, and take it to the parts store for a replacement. When I got the core back to the garage he showed me the "Modification" (I have mentioned many times) to reduce the water SLUG hit to the core on hard accelerations by bending the round inlet tube into a smaller 1/4" square opening.

So now part 2 and how it applies to this thread.

He said you have to get that 160 thermostat out of the intake and replace it with a 180 thermostat, you will be driving the car in the winter now when you are in college again. So I bought a 180 thermostat. I was in the process and he said, you need to do the Bleed on the thermostat. Drill a .125" hole in the ring of the thermostat. That will allow trapped air to get around the thermostat. SO I DID. It has worked great since 1971 in every personal vehicle I have owned.

So Formulas, that it why I have always drilled the Stat IF it did not have the Vent hole Already there.

So did any of these people say WHY they did not agree with the mod recommended by a Master Mechanic at the Pontiac Dealership?

Tom V.

[Schurkey]

If holes in thermostats were of universal benefit, why don't thermostat engineers insist that production thermostats have holes in them? GM--Ford--Chrysler--AMC--Jeep--on-and-on-and-on sent zillions of cars out of the factory that didn't have holes punched in the 'stat.

Engineers do stuff for reasons, I hear.

Robertshaw thermostats have a tiny air-bleed stamped into the metal. I'm not saying it's microscopic, but it's a fraction of that .125 hole recommended by you.

I've seen other thermostats with a "jiggle valve"; open at rest, shut when the water pump develops flow. They'd save money not cramming that jiggle valve in the 'stat; and yet those engineers find a reason to plug the hole when the engine is in use.



Holes in thermostats are needed when someone disables the OEM bypass system. Otherwise, not so much.

[Don 79 TA]

I can say the balanced sleeve high flow stats i buy have a built in air bleed and an arrow to show the direction to install, guess that helps for "burping" the air
some of the cars i've worked on in the shop, the OE stats have an air bleed too,
i'll say its something like a tire valve stem so to speak. i remember asking my friend about it and thats what he said its for, to this day i am still puzzled how it works as i would think the air would push it close, but he said its the AF that does.... but what do i know other then they work
on cars without the bleed holes, either drill a small hole or just jack the front of the car up and warm it up to temps, that helps burp it out too

I have used drilled out stats in the cold NY winter, didn't notice anything negative about them, but those were 180 and 195 stats

if one needs a stat of lower temp settings, there's the marine option that is used on Mercury/SBC/BBC/etc
they have balanced sleeve high flows in 120, 140(might be 142), NOT cheap by any means, but then again what's $50 buy now-a-days....
but as we know all that is gonna do is open sooner and you'll still probably have issues "sitting" for periods time, but may just take a tad bit longer to get to that hotter temp... again just another option out

air flow and water pump speed, aside from radiator cooling efficiency play factors too

I've had great luck with meziere electric water pump and now using the 1.25" 2 core griffin, the 1" becool was a tad bit hotter, but i am in the high altitude dessert environment now which is why i switched, i'd love a 55gpm pump, but the 42 is working jut fine, i'll get temp creep if i run 3rd gear in the 30-35 mph zone in 97++ temps in the sun, i have no idea how hot the streets are, but certainly past 100 easily

side note i'm sure most are aware but there are certain race fuels that "cool" as well, yeah i know.... talk about $$.... but that's a whole different game....

Originally Posted by Schurkey

If holes in thermostats were of universal benefit, why don't thermostat engineers insist that production thermostats have holes in them? GM--Ford--Chrysler--AMC--Jeep--on-and-on-and-on sent zillions of cars out of the factory that didn't have holes punched in the 'stat.

Engineers do stuff for reasons, I hear.

Robertshaw thermostats have a tiny air-bleed stamped into the metal. I'm not saying it's microscopic, but it's a fraction of that .125 hole recommended by you.

I've seen other thermostats with a "jiggle valve"; open at rest, shut when the water pump develops flow. They'd save money not cramming that jiggle valve in the 'stat; and yet those engineers find a reason to plug the hole when the engine is in use.



Holes in thermostats are needed when someone disables the OEM bypass system. Otherwise, not so much.

[Tom Vaught]

If it comes down to two "opinions" on a subject I personally go with other Engineers "Opinions" (and typically those opinions are based on data vs internet BS), OR WW-II Master Mechanics who actually worked on Pontiacs and military vehicles as a real job for many years. If you think that putting a couple of small holes makes any difference with the BY Pass function, that it your opinion again. The holes are there to purge out trapped air period.

Tom V.

You can do what you want It is YOUR vehicle but leave the Engineer bashing at home.

[Schurkey]

Originally Posted by Tom Vaught

If it comes down to two "opinions" on a subject I personally go with other Engineers "Opinions" (and typically those opinions are based on data vs internet BS), OR WW-II Master Mechanics who actually worked on Pontiacs and military vehicles as a real job for many years. If you think that putting a couple of small holes makes any difference with the BY Pass function, that it your opinion again. The holes are there to purge out trapped air period.

Tom V.

You can do what you want It is YOUR vehicle but leave the Engineer bashing at home.

AGREEING with Thermostat and OEM Cooling System engineers is not "bashing" them. Thermostat engineers--and the cooling system engineers at the car-companies--are not calling for bigass eighth-inch (or bigger) permanently-open holes in the 'stats, and it's working out just fine for pretty-much every vehicle ever made. (At least, until someone screws with the bypass system.)

A hole--maybe two--may be required, when someone screws up the engineer's intended coolant bypass system. In other words, you need to tamper with the thermostat to compensate for tampering with the coolant bypass. I guess that means you need to dishonor two sets of engineers; and I'm on record as opposing that (while accepting that some method of bypass is needed. If you're going to mess with the bypass, you're likely going to need to mess with the thermostat.)

There is no need for one or more .125 holes to "purge air" when Robertshaw Engineers do it successfully with a tiny stamping in the side of the stat. A .035 drilled hole might be the equivalent. And even that isn't really needed--if you fill the cooling system the right way. Most folks don't refill the cooling system often enough for that to make a difference, but some of us do--which is why the Robertshaw thermostats, or the 'stats with a jiggle valve are kinda nice.

Which of us, in this thread, is the one who doesn't respect the Thermostat or OEM Cooling System engineers? I think it's kinda shameful to hide behind a Greatest-Generation "WWII Vet" who worked on some Pontiacs and military equipment, so that you can contradict the engineers you claim to respect.

[Tom Vaught]

Quote: Which of us, in this thread, is the one who doesn't respect the Thermostat or OEM Cooling System engineers? I think it's kinda shameful to hide behind a "WWII Vet" who worked on some Pontiacs and military equipment. Quote

SHAMEFUL?? Since you got personal, about me and my friends:

I gave a timeline on when the first information on the bleed hole was presented to me.
(By a WW-II Mechanic), How many Cooling Engineers names from Ford, GM, Aston Martin, Jaguar, and Land Rover would you like me to post up as far as OEM Engineers go?

While we are at it post up all of the OEM Engineers who signed off on your Mickey Mouse Oil By-pass you constantly post and ADVERTISE about.

Tom V.

[Tom Vaught]

Here are a Few:
Jerry Miller Ford GT Cooling
Chad Higgins, George Sohm, Wally Beiber, Bob Farkis, Nathan Fogg,
and Li Lee (Engine Design Modeling).

I think they all have worked in Ford Research or Advanced Engineering so not a
WW-II mechanic who you chose to Bad Mouth.

Tom V.
I can post up the Other Company people but I think these few make my point.

We are talking about a bleed hole being .125" in diameter vs say .050" in diameter
before you got personal.

[Half-Inch Stud]

T-stats sit loose enough in the crossover groove to leak a little. A drill hole is gonna assure the little leak.

Meanwhile the Bypass path is a big internal path back to the heat source, Where the HOT Coolant is able to mingle-tingle the T-Stat.

We all can hope there is enough Balance in the Left��Right bank flow to allow a fairly uniform Bank flow throught the T-Stat.

Hmmm, Bank-Balance is a bigger concern for balanced flow (Balanced Head Heat) than a tiny drill-hole that may enable a SLIGHLTY earlier T-Stat opening, with no effect on regulating.

Seems nice to pass some warm coolant into a (-20F) stone-cold radiator than to have a HOT gush suddenly showup.

[roger1]

Originally Posted by Half-Inch Stud

Seems nice to pass some warm coolant into a (-20F) stone-cold radiator than to have a HOT gush suddenly showup.

Thermostats open slowly.

[Tom Vaught]

Excellent Post, HIS, Back to the way things really work, and why they were engineered the way they were for engines.

Bart, or Stuart, please remove the personal attacks on some of my "Teachers" just because they served in WW-II and many years after in a GM Pontiac Dealership.
By the way that gentleman' SON went to work for GM and wound up retiring at a Global Manager in Parts & Service. So the SON must have learned something from WW-II "DAD"

Tom V.

A DECENT TEMP IS BASED ON THE ENVIRONMENT THE SPECIFIC VEHICLE IS SUBJECTED TO, OPINIONS MEAN NOTHING. TESTING WITH DATA MEANS EVERYTHING. LET THE VEHICLE TELL YOU IF IT IS HAPPY.

[Schurkey]

Originally Posted by Tom Vaught

Bart, or Stuart, please remove the personal attacks on some of my "Teachers" just because they served in WW-II and many years after in a GM Pontiac Dealership.

"Teachers" and "they" indicate more than one person. Far as I know, you only had one WWII mentor as described. ("Delbert, the World War II Mechanic")

Point out the part where I attacked him.

[Formulas]

Zillions of stock camshafts, connecting rods, pistons, points distributors, stock air cleaners, oil bath air cleaners and a plethora of other crap left auto manufacturers that quickly gets thrown out

What a weak foundation for an argument against a modest hole in a thermostat especially when alot of people are doing it with positive results

[Tom Vaught]

Let it go, Formulas. My Father had seven battle stars in World War II in the Pacific on the Command Battleship California, Purple Heart, and other Medals. His brothers served in the war too, as did my father-in-Law. The Manager who hired me in Ford, never served over-seas, BUT he was in charge of over 300 Rosie the Riviters who built Bombers at Willow Run Airport in WW-II. And the list could go one and on. Mr Forrest was the only one, I personally knew, who taught Mechanics in WW-II, Worked in a PONTIAC DEALERSHIP for many many years after the war, had every certification that GM offered, (except for Automatic Transmissions), Raised a fine son, who went to very high places in GM management, so in my opinion Mr Forrest was far more than just a simple WW-II mechanic. I guess you could say that Mr Perry was a WW-II Mechanic/Aircraft Builder Supervisor who later ran the Le Mans teams for Ford in 1966, 67, 68, & 69.

So I had a lot of good Teachers. All that being said, Mr Forrest had his suggestions on how to do things, as do I, and others here on the board. I paid attention to what he and Mr Perry said.

Tom V.

[68lemans462]

I run alum griffin radiator and stock 7 blade fan clutch setup with shroud. Can't remember which T-stat... Car runs at about 190 most of the time. Will creep up above 200 sitting in traffic but it always drops quickly as soon as the car gets going... Best thing I ever did to cool the car down, install alum heads..

[promptcritical]

Who's going to be the last dog to pee on the fire hydrant here. LOL

[68lemans462]

Originally Posted by promptcritical

Who's going to be the last dog to pee on the fire hydrant here. LOL

I know who my money is on!