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I know this has been discussed many times but my car is over heating. I took it to my mechanic, he said pull the thermostat and run it without one. I did and the car ran fine and the temp gauge went up about half way. Listening to advice of many on the this site I felt I had to have a thermostat (why do I have to have one if I'm not driving in the winter?) so I put in a new 180 now it doesn't run as hot as it did with the old one. Obviously my old 180 thermostat was bad.With the new thermo the temp gauge almost tops out but not all the way (a little over 3/4) like the old thermo. Ok so I can do one of two things, put in a 160 (some here have advised not to do that) or I can take my mechanics advice and run without a thermostat (I figure we have a thermostat in there for some reason but honestly don't know why). So what do you guys think, run the 180, 160 or nothing? BTW I have the stock fan shroud and a new 3 row rad.
 

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The way I see it I don't want a three dollar part screwing up my 8k motor. I don't know what is so bad about having free flow cooling I would like to see what some of thr Pro's got to say about this too.
 

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I have always heard (and personally believe) that a slightly warm motor will outlast a slightly cold one.


If it doesnt blow coolant out the overflow (assuming a good radiator cap that's the correct pressure) with a 180 thermostat, I'd run one.
 

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The job of the thermostat is to slow the flow enough to actually have a chance for the coolant to cool in the rad. So driving at speed you might be alright without one, but in heavy stop and go traffic you might have troubles.
 

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All cars were designed to run with a thermostat. Since most of them do it successfully, wouldn't it appear that running without one to keep from overheating is treating the symptom instead of solving the problem? HERE is an excellent article that goes into some detail on what the cooling system does, and why it requires a thermostat to operate. Read the small section on "Nucleate Cooling Phase" first, then jump to the paragraph on "System Pressure". Pretty good article that will clear up a lot of questions, and dispell some myths. Enjoy!
 

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This is one of those issues where common sense gets in the way of the truth. One would think that getting rid of the thermostat and letting the engine run cooler would make perfect sense. However cooling systems are designed to have the engine operate in its most efficient range. First of all you should consider that friction is a function of temperature for oil. That means that oil that is designed to be best at 180 degrees filling gaps between parts that are also supposed to be at 180 degrees won't work as well at 160. Why, couple of reasons. First the parts need to expand in order to achieve what was originally engineered to be the operating clearance at a specific temperature range. The viscosity of the oil is also designed to maintain its lubricating ability within an optimum temperature range. Most of our era engines are designed to work at 180. Friction and wear increase measurably at lower temps.

Next thing to consider is that your engine will have cold spots and uneven expansion if the thermostat is not in place. It is there to raise the temperature uniformly prior to initiating a larger coolant flow. Again, the system was designed to operate at 180.

Get a good guage and check the temperature. Also check for pressure in the system so that you don't have any tiny leaks. Make sure the cap is the right one for the car and is operating properly. Check for Carbon Monoxide in the coolant which will tell you if you have a blown head gasket or worse. Backflush the block. Just like people cars have certain diagnostic tests that point to the sickness and the cure. Better to know what the cause is before you take the painkiller. Sometimes the aspirin just covers up the problem and the next thing you know it's gotten a lot worse.
 

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You're fine. I'll wager you have an aftermarket temperature sending unit, which are notorious for reading high on the gauge.

The key point is that the gauge reading is not accurate: high or low. What is accurate is the change from normal conditions to abnormal conditions. Once you have mentally calibrated your temperature gauge with your thermostat operating correctly, just pay attention when it doesn't read that way any more.

Stick with the 180* thermostat and be happy! :)
 

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After thinking for awhile, something else came to mind (should have been the first thought). You need to make sure the engine is actually overheating, and that's square one.

Then......
If a known gauge verifies a heating problem, it's probably due to either:

1. Carb running lean

2. Timing off

3. Radiator plugged and not flowing adequately.

So, read your plugs to see if it's running the right mixture. White plugs are due to running lean. If that's the case, put larger primary jets in the carburetor.

If not lean, your timing is probably off. I'm sure your mechanic checked the timing since it's one of the main reasons for a lot of cars running hot. What he might not have checked is to make sure the timing mark is in the right place. These old Mustangs can often slip the hub on the dampener, and the mark has moved. TDC will need to be verified, and a new mark made on the dampener to show where it is now. This mark can then be used to set the timing to the proper advance (at least until it moves again).

A buildup of junk in the heater cores is cured by taking the radiator to a shop and having it rodded, or replacing the radiator. It's a bit cheaper to have it rodded, so if it's almost new, that would be a good option. If it's old, or history is unknown, you may want to just replace it.

Hope this helps some.
 
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