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Old 09-27-2009, 10:57 AM   #1
Old Rotor Head
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Default Run without thermostat?

I had a stuck thermostat several weeks ago. I couldn't find one that night so I popped it out of the housing and off I went.

I've been running that way for a month in sunny Florida and the eng temp has never gone above 180.

Is the any issues when running without one??
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Old 09-27-2009, 11:11 AM   #2
ipuig
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You will once the ambient temperature starts to drop.
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Old 09-27-2009, 11:57 AM   #3
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The engine can run too cold too...

Shorter engine life
Higher emmissions
More frequent oil changes required
Could effect power and fuel economy

Peter
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Old 09-27-2009, 07:34 PM   #4
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Quote:
Originally Posted by lionelhutz View Post
The engine can run too cold too...

Shorter engine life
Higher emmissions
More frequent oil changes required
Could effect power and fuel economy

Peter
Now you got my attention. Next weekend I'll get one.
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Old 09-27-2009, 07:43 PM   #5
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Running without a thermostat is not the way to go.

In fact, it can actually cause an engine to run hotter eventually.

The reasoning behind this is:

As the engine warms up there is a certain restriction that the thermostat induces. This restriction will slow the coolant down and cause it to stay in the radiator longer. This causes the heat to 'exchange' as it's supposed to.

If the coolant flows faster through the system it doesn't pull the heat from the heads and block as it should because it doesn't stay in the heads and block as long as it should either.

It's all about the coolant trapping the heat, pulling it from the pieces that get hot.

Remember also, that if you run 25% antifreeze (for it's anti-corrosion properties) with 75% water (assuming you CAN run that small an amount of antifreeze from a winter protection standpoint) you will get a better coolant mixture. Water has less surface tension than glycol/antifreeze so it will get up into the nooks/crannies better to extract the heat.

There are a LOT of good readings on the web about cooling systems. The experts all seem to agree with the above.

I do hope this helps,

Jim
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Old 09-27-2009, 07:47 PM   #6
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AND, as the Old Rotor Head alluded to...

Running too cool will not allow the water in the engine oil to burn off as it should. Every time you run your car and it warms up, and then you shut it off, there is condensation that forms INSIDE the block and heads where the oil runs.

If you don't allow the engine to warm up sufficiently then this water will not be boiled off as it should. Bad juju.

Jim
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Old 09-27-2009, 10:55 PM   #7
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Quote:
Originally Posted by Hudson View Post
As the engine warms up there is a certain restriction that the thermostat induces. This restriction will slow the coolant down and cause it to stay in the radiator longer. This causes the heat to 'exchange' as it's supposed to.

If the coolant flows faster through the system it doesn't pull the heat from the heads and block as it should because it doesn't stay in the heads and block as long as it should either.
There is absolutely no truth to this. An old gearhead tale.

Any car that only overheated without a thermostat had some other cooling system issue because the overheating was not caused by the coolant flowing too quickly.

Peter
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Old 09-27-2009, 11:06 PM   #8
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and you just keep believing that Peter and spreading untruths and others will suffer from the same issue.

In FACT, the professionals who design automobile cooling systems run thermostats in the cars for THAT reason and others.

I'm sorry you didn't do your research over the years as I have.

Jim
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Old 09-28-2009, 08:33 PM   #9
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No, not one professional who designs cooling systems has ever put in a thermostat so that the coolant could go slower to keep the engine from overheating. If you know anything at all about thermodynamics you would know that claim is complete rubbish. The thermostat is there to keep the engine at the designed operating temperature.

It's the equivalent of saying that putting a fan on the radiator will cause the car to overheat because the air is moving over the radiator too fast to cool it. We all know that isn't true.

As I posted before, If the car only overheats without a thermostat then there was something else went wrong. It was not because the cooling was flowing too fast. Most likely, the crappy impeller on the water pump quits pumping correctly without some back pressure.

The "car experts" who have perpetuated this myth over the years really **** me off. I've even read about it in magazines for crying out loud.

Peter
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Old 09-28-2009, 08:38 PM   #10
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Quote:
Originally Posted by Hudson View Post
AND, as the Old Rotor Head alluded to...

Running too cool will not allow the water in the engine oil to burn off as it should. Every time you run your car and it warms up, and then you shut it off, there is condensation that forms INSIDE the block and heads where the oil runs.

If you don't allow the engine to warm up sufficiently then this water will not be boiled off as it should. Bad juju.

Jim
Only in extreme low temperature circumstances where the engine does not come up to operating temperature..i.e. driving short distances. Heat a pot of water to 150 degrees and see how long it takes to evaporate....
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Old 09-28-2009, 08:48 PM   #11
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Not thermostats...you are correct. ..But restrictors are added frequently to modified and race engines to control flow !
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Old 09-28-2009, 09:00 PM   #12
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Quote:
Originally Posted by Old Rotor Head View Post
I had a stuck thermostat several weeks ago. I couldn't find one that night so I popped it out of the housing and off I went.

I've been running that way for a month in sunny Florida and the eng temp has never gone above 180.

Is the any issues when running without one??
Like most have said, I'd replace it.
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Old 09-28-2009, 09:12 PM   #13
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Quote:
Originally Posted by lionelhutz View Post

The "car experts" who have perpetuated this myth over the years really **** me off.
Peter
Obviously
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Old 09-29-2009, 08:11 AM   #14
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Quote:
Originally Posted by Hudson View Post
As the engine warms up there is a certain restriction that the thermostat induces. This restriction will slow the coolant down and cause it to stay in the radiator longer. This causes the heat to 'exchange' as it's supposed to.

If the coolant flows faster through the system it doesn't pull the heat from the heads and block as it should because it doesn't stay in the heads and block as long as it should either.
I think the scenario of overheating without a thermostat can happen, but the explanation is bunk. Higher velocity in itself won't cause overheating. The water may spend less time in the engine and radiator with each pass, but it makes more passes, so net time for heat exchange is the same either way.

I think what's going on when a restriction at the engine outlet helps, is that it has increased coolant pressure in the engine, raising the boiling temperature. Regardless of what a temperature gauge says, there can be spots, like near the exhaust ports, where the water gets much hotter. Coolant in these areas can flash to steam without sufficient pressure.

As I recall, this was mostly a problem which came up years ago in cars with a very low, or no cooling system pressure. A restriction at the outlet was an effective bandaid.

It's also possible that in these low pressure systems, the inherent pressure drop at the pump inlet, or within the pump itself, was enough to cause hot coolant to flash to steam. Slowing travel through the radiator could have produced a lower temperature at that point, and made it a little more resistant to changing to steam. Lowering the circulation speed could also have resulted in less pressure drop on the suction side of the pump.
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Old 09-29-2009, 10:51 PM   #15
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Quote:
Originally Posted by lionelhutz View Post
No, not one professional who designs cooling systems has ever put in a thermostat so that the coolant could go slower to keep the engine from overheating. If you know anything at all about thermodynamics you would know that claim is complete rubbish. The thermostat is there to keep the engine at the designed operating temperature.

It's the equivalent of saying that putting a fan on the radiator will cause the car to overheat because the air is moving over the radiator too fast to cool it. We all know that isn't true.

As I posted before, If the car only overheats without a thermostat then there was something else went wrong. It was not because the cooling was flowing too fast. Most likely, the crappy impeller on the water pump quits pumping correctly without some back pressure.

The "car experts" who have perpetuated this myth over the years really **** me off. I've even read about it in magazines for crying out loud.

Peter
Absolutely agree!!! It's like saying that putting AC fan on high seed won't cool the car.....man
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Old 09-29-2009, 11:17 PM   #16
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Dude...let me put it to you like this. Your messing with a $20,000 or so dollor car just drop the $80 and put a thermo in
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Old 09-30-2009, 08:34 PM   #17
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The engine was designed to operate at a specific temp. and without the thermostat in the engine it won't ever get to that temp.
So put in the stat and it will perform better then it is now, and most likley your mpg will improve also.
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Old 09-30-2009, 08:37 PM   #18
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Quote:
Originally Posted by xboxexpert View Post
Dude...let me put it to you like this. Your messing with a $20,000 or so dollor car just drop the $80 and put a thermo in
Ok, ok I put it back in this weekend,,,,,,,,,$29.00 at NAPA
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Old 09-30-2009, 08:37 PM
 
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