Aussie-

As I stated in my first post to this thread, I agree with several other people, more than likely this problem exists in either the temperature sending unit or actual gauge. I threw out the thermostat and coolant information in the event that the sending unit or the gauge were *not* the problem and also just for information’s sake. Some people think if a little coolant is good, then a lot will be better, some people think the faster the mixture flows, the better it will cool. This is not always the case.

I've read cooling FAQ's and have also had more than my share of real life experience. I didn't specifically mention a "rate of flow" other than stating that if the water doesn't stay in the radiator long enough, the water will not cool down and therefore the engine will not cool down.

I'm not exactly sure what I could be "off" about, but if you have a differing opinion, I would be interested in hearing it.

 

All coolant/anti freeze does is to change the specific gravity of water (change surface tension). Altering the specific gravity alters the boiling or freezing points of water. Thats why water can be at temps higher then 212 (boiling at sea level) without turning into steam. Its also the reason water will not freeze while in your block at -45 degrees. They add rust inhibiters to coolant/antifreeze as well, but the real reason for its use is to change the properties of the water.
I disagree with the idea that the thermostat restricts flow inorder to provide proper time for heat transfer. I believe its only function is to allow water to heat up in the block, so the engine will perform at a predetermined temperature. If you notice , the temp gauge generally stays in the same place regardless if its summer or winter during normal operation.

 

How's this for a novel idea....go buy a thermometer at your local auto parts store and see what the temp is.

 

Almost forgot, open the rad cap, put probe in, let run, see what temp reaches after 10 min or so

 

if it dont stay in the radiator long enough then "rate of flow" is too high = same thing (or you have a hose missing and it is all running out on the ground???). That FAQ articlesays that "too fast a flow = water doesnt stay in rad long enough to cool down" is a myth and provides an explanation. Read it, disagree if you wish, provide the math that says its wrong.

I run coolant in my car to raise the boiling point and prevent further corrosion (see bodyputtyless post - he's right on the money). You can run just water if you think the heat exchange properties outweigh this. Bottom line, if you can tell the difference via your temp guage then there is something far more wrong with your cooling system that the liquid running around it.

if you're going topost stuff"just for information's sake", make sure it is correct or call it an opinion

 

do you have the proper cleveland specific theromstat in the car and also is the restrictor in the motor under the thermostat

 

Heres the story:

Ok the radiator was checked it had50% blocked, I had the radiator re-cored and acid dipped.(nice and clean with no blockage) I then had a new 180* thremostat installed as a prevenitive messure and the old one was thrown away. When I start the car nowthe gauge shows cold after the car has been running for 15 mins the gauge starts its trek from cold to the temp lettering, another 5mins and the gauge needle will move over to the line before the H and stay there. (I would guess the gauge is working fine) so I guess its the sending unit.

Note the radiator has never boiled over. I have even added an after mkt. water bottle to the mix as a precaution.

When I first got the car the needle would sit pointing down between the e & m in the word temp , after it was warmed up.

 

72351CJ-
Have you checked to see if the car really is actually running hot? Ponyx2 suggested getting a thermometer to test it, that sounds like a good idea. Is it possible that the new thermostat is bad? Is it really opening? Does the top radiator hose get hot? I’m not sure that a bad sending unit would cause the problem that you described in your last post.


Aussie-
I totally agree on the use of the proper mix of coolant and water. I also agree about what coolant does to the properties of water. I understand the boiling point change and corrosion prevention and agree that the benefits of those *far* out-weigh the use of water alone, there is no argument there at all. Using water alone is not an option, nor would I ever suggest that it was.

However, we may have to agree to disagree on the flow rate issue. I stick by my "opinion" that the water/coolant needs enough time in the engine to pull the heat out of the block and heads. Likewise, water/coolant needs enough time in the radiator to shed its accumulated heat before returning to the engine. If this doesn't happen, like I stated before, you are just circulating hot water.

I would imagine that for every article that you can find on the Internet that says that flow rate is not an issue, there is probably a different one that states it actually is. That’s the double edge sword that is the Internet… there is a ton of information, both correct and incorrect. Your mileage may vary, what works in one situation may or may not work in another, etc.

Picture setup "A" of a regular automobile radiator with no hoses connected. If you were able to pour hot water into it faster than it actually flowed out the bottom, the water would spend time in the radiator. OK, now picture setup "B" with the same radiator except you cut the bottom of the radiator off so you can pour hot water straight through. It makes sense that in setup "A" the water temperature exiting the radiator would be cooler than in setup "B". If the water temperature exiting the radiator is cooler, it stands to reason that it can absorb more heat when it is in the engine.

I had a friend who had a 1934 Ford pickup with the original flat-head four in it. He was always having overheating problems. Those vehicles didn’t come with thermostats. He put one directly in the radiator hose and that solved his problems.

I am, by no means, anywhere close to an expert at thermodynamics, nor have I ever claimed to be. Also, I really don’t mean to be argumentative, I am just trying to apply common sense and my experience to the situation. When troubleshooting problems, I’ve learned that the more options you try, the better chance you have at solving the problem.

Thanks for your input, I look forward to a constructive reply. We may not be able to solve all of the world’s problems, but maybe we can help 72351CJ solve his.

 

OKI finnishedthe little test about 10 min ago. started the car let it warm-up for 20min checked the top radiator hose it was hot and I could squeeze it freely,opened radiatorcap inserted thermometer, It quickly climed to 150* and held there. Checked the gauge and it was onthe line before the H....

 

Top radiator hose being hot tells me that the thermostat is actually opening, but if the test thermometer only goes to 150* and holds, the thermostat probably isn't open 100%. The good news is it doesn't look like it is actually running hot. I'm guessing the next step would be to replace the sending unit. As stated before, you can probably find one for about $15.00 and they are really easy to replace. Make sure you get the one for a gauge and not just a light. Good luck, keep us posted.