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Old 11-11-2003, 06:37 PM
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over heating?

i have a 77 camaro with a 350 out of a 77 camaro i run a 160 thermostat in it and the temp guage when i am on the highway goes up to 195 to 200. i have 3.73 gears so i am turning about 2500-3000 rpms is there anyway i can get the car to run cooler? could i just take the thermostat out? thanx

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Old 11-11-2003, 06:39 PM
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Put in a 185 thermostat.
Put on a 15# rad. cap.
The coolant needs more time in the motor to help cool.

The Knowledge Base has quite a few postings on this subject.
http://hotrodders.com/search.php?s=&...by=&sortorder=
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Old 11-11-2003, 06:44 PM
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what is a 15# rad. cap? and why a 185 thermostat
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Old 11-11-2003, 06:44 PM
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The car will probably run hotter if you yank the thermostat. The thermostat serves a purpose. It slows down the flow of the coolant through the radiator and block so the coolant can do it's job. It has to pull heat from the block and dissapate it out through the radiator. If the coolant is flowing to fast it doesn't have time to pull the heat from the block so the radiator can cool it. You will have a hotter running engine.
Do you have a shroud on the radiator? That would solve most of your problem if you don't...
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Old 11-11-2003, 07:08 PM
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Is the air dam in place under the front of the car? if not it`ll run hot. is the resovoir in place so the coolant system can burp itself? if not the same results.
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Old 11-12-2003, 12:21 PM
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Any luck yet ?
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Old 11-12-2003, 02:03 PM
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195-200 degrees is pretty normal. I wouldn't worry about it, unless it gets hotter in traffic.
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Old 11-12-2003, 05:07 PM
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There is no cycling of air & coolant through the engine block, so slowing down the flow of coolant through the engine block will not make a difference in the temperature. The thermal conductivity of the coolant does not change. As long as the coolant entering the engine is cooler than the coolant in the engine, higher flow rates will equal a cooler engine. A higher flow water pump is more likely to fix youre problem than a higher temperature thermostat. Now they do make some “high performance” thermostats that allow a higher flow at the rated temperature that may also help.
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Old 11-12-2003, 05:37 PM
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Quote:
Originally posted by Wings
There is no cycling of air & coolant through the engine block, so slowing down the flow of coolant through the engine block will not make a difference in the temperature. The thermal conductivity of the coolant does not change. As long as the coolant entering the engine is cooler than the coolant in the engine, higher flow rates will equal a cooler engine. A higher flow water pump is more likely to fix youre problem than a higher temperature thermostat. Now they do make some “high performance” thermostats that allow a higher flow at the rated temperature that may also help.
I don't understand your first comment that there is no cycling of coolant through the engine block. Heat exchange form the iron in the block to the coolant isn't the problem. Heat exchange from the radiator fins to the cooling air is a BIG problem. If you do a log mean temperature difference analysis of the radiator you will find that there is a water velocity that if exceeded, will result in reduced heat transfer from coolant to air, increasing temperature of the entire system. If you do not allow the water enough residence time in the radiator to transfer its heat to the air flow, it will go back into the block hotter than it should. You are correct, the thermal conductivity of the coolant doesn't change appreciably in the narrow temperature range that an engine works under but thermal conductivity isn't an important parameter in the coolant. Since flow in the system is turbulent, conductivity is negligible - conduction is the primary heat transfer mechanism. On the water side, unless there is a significant buildup of scale on the metal surface which acts as an insulator against heat transfer, there is no problem with the convective cooling of the iron in the engine. However, since all heat transfer is a function of temperature difference, the hotter the coolant in the block i.e., the closer the coolant temperature is to the iron temperature, the less heat will be transferred to coolant and the result is a higher overall temperature of the engine. My experience is that water flow rate is rarely the problem in cooling an engine. Rather, air flow and/or radiator size is the problem. The air side of the heat exchange process is significantly less efficient than the water side.

All that being said, 200F is not a problem at all. Modern smog engines are designed to run at 240F. We just changed the thermostat in my son's Explorer and it was rated to open at 210F! My Willys runs at 210F all day long in the summer.

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Old 11-12-2003, 08:56 PM
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Willys,
Go to www.radiator.com/radiators/articles/radiator-myths.html
and read:

" Car Radiator Myths "

- Too much coolant flow is bad. This long-held radiator myth will not die. Too little coolant flow can be bad, but at normal and high operating temperatures, the rate at which coolant moves through the radiator does not change the amount of heat that is dissipated by the cooling cores. Sure, the mean temperature of the coolant will rise if it flows faster, but the amount of cooling will not be reduced.

So I guess at least this manufacture believes your car will not run any cooler if you slow down the flow

Last edited by Wings; 11-13-2003 at 03:37 PM.
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Old 11-12-2003, 09:04 PM
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Me and my Dad always yank our thermostats when it is warm out, runs cooler.
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Old 11-13-2003, 08:17 AM
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Quote:
Originally posted by Wings
Willys,
Go to http://www.radiator.com/radiators/articles/radiator-myths.html and read:

" Car Radiator Myths "

- Too much coolant flow is bad. This long-held radiator myth will not die. Too little coolant flow can be bad, but at normal and high operating temperatures, the rate at which coolant moves through the radiator does not change the amount of heat that is dissipated by the cooling cores. Sure, the mean temperature of the coolant will rise if it flows faster, but the amount of cooling will not be reduced.

So I guess at least this manufacture believes your car will not run any cooler if you slow down the flow.
that link doesn't work.

Bummer. That means my BSME degree from Fresno State is bogus and all the heat exchangers I have desinged over the past 30 years don't work. Oh well, I guess I can get a government job somewhere!!
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Old 11-13-2003, 08:58 AM
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willys, guess I can get a government job somewhere.
Let me know also they have better health care with our tax money.
After all these years of experience we just don't know yet on cooling a motor, at least we do not have any problems with it, so I guess we don't know to much.
Time for the government job.
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Old 11-13-2003, 03:51 PM
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Haa...no wonder it didn't work...I work for the government. Really I'm just a newbee here, try the link again (I think I got it fixed) and let me know what you think. It may be just their way of pushing products.
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Old 11-13-2003, 05:42 PM
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Most of their truisms in that list seem correct. I would like to see the science behind their contention about flow rate though.

Think about the implications of the temperature of the water going back into the engine; If the iron in the engine is, say, 250F and the water coming from the radiator is 150F, then that 100F temperature difference (think of temperature as voltage in an electrical analogy or pressure in a hydraulic analogy) will cause the transfer of a certain amount of BTUs (heat) from the iron into the water.

However, if the water coming in is 200F, then there is 50F temperature difference and that 'voltage' or 'pressure' is only half of the former so only half of the BTUs will be transferred.

Worst case is water coming in at 250F in which case there is zero temperature difference/pressure/voltage and no heat is transferred. Thus the only way for the engine to reject heat is to get hotter to establish a temperature difference with the water that will force BTUs to again flow into the water.

Water flow rate in a heat exchange system like an engine/radiator is a balance - flow can be too high or too low - both are bad. The one flow that can't be too large as far as heat exchange is concerned is the cooling air flow. That radiator fin/air heat exchange is the weak link in the entire system and air flow is the most critical parameter. As I said above, many if not most cooling problems can be traced to air flow problems.
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