I recently replaced my old cracked rad on my 86 4runner with a fresh new 2 core CSF rad from radiatorbarn, and did a full system flush and burped it and everything, new coolant, new water, and i had just bought a t-stat about a month and a half ago so i just stuck with this one and drilled two small holes in it as suggested on cheap tricks site, well, one was sufficient, but i figured two would be fine.. well, now im not sure if that was such a good idea.. on the highway its heatin up, on city driving and alot of idling and stop and go, interestingly enough, it stays cool and right in the proper range and the fan kicks in when needed.. headgaskets fine as well, no problems with that, yet.. so can those holes effect whether or not the t-stat opens and closes? does it need a certain amount of pressure being forced on it to open? or could it just be that it still has air in the system?

 

if you drilled holes in it..then that means SOME coolant will be constantly flowing..correct guys?

if so then it shouldn't heat up at all.

kinda like running with no thermostat..doesn't that just make the coolant constantly circulate, and therefore the motor stays cooler?

 

You still have air in the system.

Park it on an incline (rad being highest point) and squeeze the hoses as you fill it. This will help burp out any air in there. Drilling two holes in the thermostat won't make it run hotter. If anything, it helps it run cooler.

I pulled the thermostat out of my race car, and it works just fine. Higher HP cars don't do this though, as you can cavitate the pump and cause an air pocket by not having a thermostat in there.

 

no camo, a small hole (1/16) won't hurt, as it's a common fix to the temperature overshoot for the 22r's.

But running no thermostat will cause overheat. Here's why, your right about the constant flow, however, because of this constant flow, the coolant will not stay long enough in the radiator to cool down. Eventually leading to overheating.

 

ah hah, i was thinking about that inside my head as i was typing LOL but went ahead and posted anyway.

thanks for the clarification!

 

DC is correct though as running no t-stat in a race car is ok if it's a drag car with minimal HP or a 2 minute SCCA solo car.

 

Interesting...never thought of it that way. You would think the constant flow would prevent the coolant from ever reaching even a normal operating temp. Guess it depends on the flow and efficiency of your radiator. Antifreeze/water ratio might also play a factor in this one.

Also, I've had a few thermostats stick open on me and actually ran like that all summer once. 100+ degrees out a few times and no overheating. Ideas?

 

The only problem with not running a t-stat is that the engine will not get up to proper operating temperature.

You're right about the coolant not staying in the radiator for long. But, at the same time, the coolant will not see much of an increase in temperature from the engine because it is constantly flowing through it. It all balances out except for the fact that your vehicle will run cooler because the coolant is not being held in one place until it gets hot enough to open the thermostat.

 

hahah ok, make a 3 hour run on the highway and you tell me what happens to your motor. You obviously don't know much about heat transfer and fluid flow. By no means will it run cooler. Everytime that water circulates through the engine block it will pick up a few degrees. Each and every time until that water will eventually get hot enough that the rad cannot cool it down.

 

I have and nothing happened except it never reached operating temp....

Really? I don't think we've ever met.

Care to share how you came to this conclusion?

So going by your logic the radiator is there and does nothing?? Why is it there then? If the water can pick up a few degrees while it runs through the block then what is stopping it from shedding a few degrees when it runs through the radiator? As long as your cooling system is in good shape (i.e. your radiator is not clogged, fan works) you will not overheat running without a thermostat.

 

a radiator is designed to cool down static fluid not fluid in motion for one. It might cool it some, but not to where the engine can make use of it. And by a few degrees I mean like 10-15. each time the warmer fluid enters the engine it comes out that much warmer. meaning the rad has to cool that warmer water even more.

 

do yourself a favor and google what happens to a motor when the thermostat is not in. it might seem it runs cooler but I guarantee you the actual engine temp will be higher. if you don't overheat, you will eventually warp a head and blow a head gasket.

 

my only answer to this is short runs without driving hard.

 

Why don't you do yourself a favor and ask some engineers what they think about this before you go and post misleading information?

 

Haha...easy gentleman, no reason to get heated (no pun intended). I'm sure it's possible, but I've run long distances on the highway in 100+ heat with a stuck-open thermostat and came nowhere close to overheating. In fact it stayed a bit below normal operating temp. I personally believe it all has to do with the efficiency of the radiator. We should all go buy some old beaters and try it out mythbusters style!

 

interesting convo.. okay, thanks.. i thought i had it all burped out but apparently not.. ill prolly drain some coolant and dump some more distilled in there, im runnin a 50/50 mix but i really dont think its necessary.. and i prolly shoulda mentioned this before, but i drilled two 3/16 holes, two 1/16ths just didnt seem like enough..

 

lol engineers meant there to be a thermostat in there for a reason, one of them being as you said to keep the engine actually warm, but another to keep it from overheating.

yes it will take longer to get up to normal operating the that it would without one. What's the side effect of this? Well for one on the 22res, 3.0, 3.4 and everything electronically controlled, it will cause the engine to run rich because the ECU thinks the engine is still cold. One the 22r's you "might" see tyhe choke engaged for a longer than normal period. Again leading to an over rich condition and probably barely drivable till the choke opens.

 

I would also like to add since I got a chance to think about it some more, but with stuck open thermostat I think the difference there is the fact the thermostat is still in there restricting flow allowing it to cool a little better than if there was none in there to begin with.

I like the myth buster idea though. I don't think they ever done that before.

Someone needs to go email Jesse from their pirate account.

 

The xxxtremenous is right. All you gotta do is run a google search, if you don't think it logical. Coolant has to stay in the radiator long enough to be cooled sufficiently. If the thermo, or anything else, is not there to regulate the flow it'll just run through without allowing heat to dissipate. Even a properly operating cooling system (ie, radiator) gets very hot. But, in that case, the coolant's in the radiator long enough for heat to transfer.

 

That's a common myth, but wrong.