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Okay, I have been known to be wrong from time to time........

Somebody recently posted a question about thermostats, and I told him it was okay to run without one for a while.......

But somebody else says this can do harm! Id hate to think id given the poor guy the wrong advice!

Any thoughts people? I had thought that a bloked thermostat can cause pressure problems in the cooling systems, and if the thermostat had failed, it would do more harm than good to leave it in there. I thought it was okay to run the car for a couple of days without one, it would just take longer for the engine to warm up. I guess it depends on how long it takes you to track down a new one that fits.

However, it was bought to my attention by someone at this site that running without one for any length of time causes problems with fouling cause you need the choke out for longer while the engines warming up. Is an extra half an hour of choke over two days going to do any serious harm? Im worried now!

Come on, I dont mind people telling me im wrong........
 

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actually....

Actually...the thermostat restricts the coolant-flow at the head to allow the radiator to work...you see, if the coolant is allowed to simply flow through the radiator at the rate the water pump pushes, it would run too quickly through the radiator cores; thus returning to the block without much heat defusing...make sense?..it took me a while, but then that's another post all together.....good luck my friend---go z racer
 

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i dont think it will cause any harm but i would be sure to keep a close eye on the temp gauge. When i first got my z it would over heat all the time so i took the thermostat out figuring it was summer and the car would run cooler but instead it actually ran hotter without the thermostat then with it. The only thing i could figure out was that the water was going through the system to fast to be effective, other then that i had no bad effects on the car.
 

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Re: Thermostat

I guess if the t'stat is not opening and causing the car to o'heat it's OK to remove it until you can get a repl. in an emergency.
BUT:
Removing the t'stat can also cause the car to o'heat as well by not allowing the water to stay in contact w/the water passages long enough to absord heat. Strange , what?

I've had t'stats that fail by staying too open and they at least didn't do anything other than keep the car from warming up to proper temp.
 

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safely do away with our thermostats?

Wow---great posts here, all of them...and after some thought...this might sound real stupid but, for those of us who live in the warm regions of the world, since most of us do not have motor warm-up issues, if we were to shave the blades on our water pumps, or increase the diameter of it's pulley (larger = slower), do you suppose we could once, and for all, safely do away with our thermostats?...I'm not smart enough to figure this one out...any brainiacs out there? just wondering---go z racer
 

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Re: Thermostat

Most of my friends who had over heating problems had them because the thermostat went bad and was blocking the flow of water to the head.. Every Z car that removed the thermostat out of the car had no problems what-so-ever. The car stayed cooler than ever. Most people say, if you live in an extremely cold environment then you would need the thermostat to warm your car up faster and to protect your engine against the cold. I took mine out because I didn't like to worry if my heavy duty thermostat was gonna go bad. And when it goes, it goes. More problems!!!!!

United Z Club,L.A/LB
 

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I wouldn't have any problem removing the t-stat in a pinch. If I were 'stuck' with a stuck closed thermostat and didn't have any way to get ahold of one right away, you're not going to do a bunch of damage by removing it. If the car is fuel injected and the temps stay on the cool side, it probably will run a bit rich, but with a carbed car it will just likely take longer to warm up. Depending on how cold out it is will make a difference too. It's not like the engine is going to grenade on you if you run without it for a couple of days. Better to run too cool, and a little rich than to have it overheat and warp the head or blow a gasket. Is it the correct thing to do to prevent overheating for long term? No! But is it going to hurt anything when you're in a bind? No to that too.
 

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Here's One To Try:

Lots of racing engines do not run thermostats. A calibrated orifice is installed to slow coolant flow through the radiator to allow for optimal heat exchange. So...take the inner core/spring out of the thermostat and reinstall the outer brass ring, this should keep the coolant flowing at a 'controlled' rate,(but probably will slow heat up of the engine).
Now, the folks that say they have removed the thermostat and had no ill effects probably have heavily cloogged radiators so the coolant is slowed by all the restrictions!
 

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Re: Here's One To Try:

I'm running 160deg T-stat large centerhole with two holes on the side to lower pressure and have constant flow. seems work pretty good. If yuo have good alumium radiator, then you won't need the T-stat for sure because the heat transfar is better than steel
 

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I would not do it..unless

Removing the thermostat will cause the car to run too hot, the coolant needs to be in the radiator to cool down, removing the thermostat allows the coolant to flow too freely and not cool down. I tried this once and the car overheated, In a pinch and for a short distant I would consider removing but not for any extended length of time or mileage.
 

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Re: Here's One To Try:

The race car example is not a good one. They are trying to make a compromize between two things, downforce and cooling. The try to block and cover as much of the front of the car as possible so that the air is forced around the car and therefore pushed into the track. The more air they allow into the engine area the less vacuum they have under the car.

In an attempt to "improve" their cars I've seen several people try to run without them. I guess they figure if they remove something and the car appears to run the same then that must be an "improvement" right? The trouble with this is that it throws the entire system out of wack. Yes the engine will warm up slower, is that a problem? Yes! Everyone knows that "starting an engine is the worst thing you can do." Until it reaches it's operating temperature (in physics terms "steady-state") all the wearing surfaces are out of shape from eachother. Why do you think we have to adjust the valves with the engine hot? Because when the engine is cold all the dimensions are wrong.

What about running a colder thermostat? Modern cars are very sensitive to engine temperature ... let me re-state that ... Modern cars ECUs are programmed to be very sensitive to temperature. Why? Because during cold start the fuel system is enriched so that it will actually run worth a dang as you haul ass out of your neighborhood. Americans demand that the engine run the same in any condition (and an A/C that's big enough for a building.) So to accomplish this desire the ECU will allow someone to abuse the engine. Now, back to Z cars. Our Zs don't have nearly the complexitys of modern cars. But they do have a cold start circuit. They do adjust fuel rate based on engine temperature. So if you run a 160 degree thermostat the engine will run in a constate rich condition ... sounds like a lot of posts here doesn't it?

Every Z car I've seen with overheating problems has two things in common. A worn out crappy $2.00 rad cap, and a radiator full of scale/rust. Replace these two things and your life will be much happier.

I run my '76 w/ factory A/C(original), a Modine replacement radiator, and 180 thermostat and it always stays at the center tick mark.

ConorP

The FSM recommends: Standard 180, Cold Areas 190, Tropical Area 170.
 

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5 Owners Agree !!!

Hi Kiwi_260z.
Over this past week-end here in beautiful colorado I visited a few of my more favorite junkyards/pick 'n pull yards. From what I saw at these places I would definetly say that to run a Z without a thermostat was the concluding consensus. Unfortunately I can not refer you to the owners of these 5 Z cars ( 4 260's and a 280 ) but I can answer with finality that none of these Z's had a thermostat. And all had blown engines at Number 6cylinder. Hmm........ Maybe there's another message here huh?? shane-
 
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