Maybe we're getting caught on terminology - once the thermostat is open, it can't possibly do anything other than close...to increase temp. Please explain to me how the thermostat will regulate temperatures once it is fully open. If an engine stabilizes at 200 degrees - a 160, 180 and 195 degree 'stat will all end up with a final engine temp of...200 degrees.

I have a very good concept of how it operates, thanks

 

This makes sense to me because the thermostat should keep closing to keep the temperature up. But once it is up if the engine wants to go higher, the thermostat would just sit there open doing essentially nothing. That's why I took it out because I thought it may be opening too hot.

 

Originally during break in it was 16* at idle.
Then I went to 4* per spec. It didn't change a thing temperature wise.
I took out the thermostat and it stabilized at 195 ish. I don't understand this.
That stabilization allowed me to start the timing sticky.
Now as I go through the timing sticky it is at 36 all in and 17 at idle, no stat. and still 195.
Tonight, I will pressurize the system by installing the tank and see what happens. If it is still high I will back off the timing to 12? and see what happens but I am pretty sure I was at 4 with no change.
I sure hope this doesn't mean I have some internal problem to my valve train or something. I don't believe I hear any unusual noises.

 

my understanding is that with NO thermostat there is no restriction and the water will flow too fast to cool in the rad. you really should have a therm to slow the flow and keep the water in the rad longer to have the air passing thru it cool it down

i believe retarded or (late timing) makes it run hot...not advanced

 

I appreciate the comment but I have heard this before and it does not make sense to me. The radiator and fan can remove X number of BTU's from the engine in a given amount of time. It doesn't matter if it is in one gallon or three. Yes, with higher flow the water coming out will be warmer but more water is coming out. It is the same thing. But not enough water passing through is a problem. For example what good is it to have cold water if it can't get back to the engine? Too much can't be a problem. I could be wrong.

 

The NAPA guy said that without pressurization the pump can cavitate leading to inefficient reduced flow and potential damage to the pump. I bet this is true because all pumps need a certain amount of pressure to work properly. This is called NPSH. But I bet this is more true of a very high performance or racing application. Not mine.

 

So why are high flow pumps so popular?

 

Billa... I think you mis-read my post. You're concept is correct--and is exactly the same thing I posted. We just said it in different ways. The stat 'regulates' by adjusting the amount of flow through the radiator--which allows the cooling system to cool more. If the stat stays open all the time, the system [obviously] runs too hot for the stat to ever regulate.

 

if the water does'nt stay in the rad long enough to cool, it won't cool the engine with no therm you have is the same temp water running thru the entire system. if you have a therm installed it lets the water stay in the rad longer so the air passing thru the rad cools it down then the cooler water enters the engine therefore creating lower operating temps. hope this makes sense

 

ive never had a need for 1. ive had sm blk chevys my whole life and always used a std w/p with no overheating problems.

are you just here to rip on everyones comments? i've yet to see any of you're comments aid this thread! why dont you enlighten us with you're wisdom??

 

It doesn't and here's why. The warmer water won't be in the engine as long because it is moving faster. For example lets say the water goes through 2 times faster without the stat. So instead of being 20 degrees cooler it is 10. But it goes through2 x as fast, same thing.

Actually I am complicating things. Again with a given outside air temperature and forward velocity the radiator and fan remove the same amount of heat no matter what. When the temperature is stabilized the engine is releasing the heat in many ways in exactly the same rate it creates it. This is measured I guess in BTU's. it doesn't matter how much water you push through it. More is better. less is not.

The heat is transferred to the air flowing past. no matter what the speed of the fluid in the radiator and all other things being equal the temperature differential between the air entering the radiator vs. what exits is the same regardless of the speed of the coolant..

 

Thermostat Description



The vehicle cooling system must always maintain the engine at a constant temperature in order for it to run efficiently for miles and miles of driving application. If the operating temperature is too low, fuel economy will be compromised and emissions will increase. If the temperature is left too hot for a long time, you run the risk of getting your engine to self destruct. The thermostat is among the vital components of your car?s cooling system. Its main function is to regulate the temperature and keep it at an ideal level. The thermostat is able to do this by controlling the heating and cooling devices so that the temperature is maintained at a desired level. The thermostat is a small component mounted between the radiator and the engine remains closed when the engine is warming up. This makes sure that the antifreeze does not go from the engine to the radiator until the desired temperature is reached. As soon as the correct temperature is reached, the thermostat opens up and lets the antifreeze go to the radiator to cool it. With the efficient function of the thermostat the engine is able to maintain the ideal operating temperature without the risk of overheating. Routine maintenance of the part though is vital to ensure of the reliable service of the part. If your engine takes a long time to warm up or if it is always running hot, this means that the thermostat is already damaged. A worn out or defective thermostat can cause engine wear and fuel wastage. To avoid getting expensive part repair or replacement, make it a habit to regularly inspect the part and replace it when necessary. Delaying replacement is wrong economy and a safety hazard. For your thermostat replacement need, look through our online shopping store as we stock top of the line thermostats that would fit best with your car. We support a 24/7 customer service assistance bureau that would assist you in any of your shopping concerns and queries.

 

It's probably more about the assumptions regarding the cooling system. In a properly sized and running system, the coolant coming into the engine will ALWAYS be only a few degrees warmer than the air. If the coolant is entering the engine at 200 degrees, there is a major problem with the cooling system - undersized radiator, plugged radiator cores, broken pump, etc.

In a properly operating system, the thermostat will regulate the temperature of the engine within a temperature range. It will open when it heats up and let cool coolant in and close down as the coolant cools it below its rated temperature. It's as simple as that.

AWilson - once again, I stress that you don't have a problem. The engine is supposed to be at 195-200 degrees! In fact, the manual states that temps higher than the boiling point of water are in no way objectionable as long as you don't have a leak. That's why the redline is around 250. Below 180-190 and your engine wears faster...

 

You missed the irony of my question in addition to avoiding answering. Your knowledge of heat transfer is lacking. The 'coolant flows too fast theory' is a favourite bubba legend which has been beaten to death here and on every other car web site, ad nauseum. Quit while you're behind. AWilson has it right. There, now you're enlightened.

 

The 'downside' to the hi-flow pump is that, in order to move that much more coolant, the pump expends a lot more work than a standard pump. Thus, more heat is generated than with a stock pump. If the entire system is upgraded from stock...including the availability of useable ambient airflow to pass through the radiator...that should be no problem. Otherwise, a hi-flow pump will only cause the system to retain more heat than it did before.

 

I appreciate that Z-man but the problem is that WITH the thermostat it overheats. Once it gets to 220 I have to shut down or it will run to redline on the temp gauge fast. So there is the confusion. No stat and it stops at 195. I don't get it because the stat was fully opened at 180 in a pot on the stove.

 

You do have a problem. But, you can ignore it for a while if you want. No matter what anyone else tells you, a C3 with NO stat should stabilize at 160-175F; some small blocks with A/C (and with the A/C off) will stabilize at 140F. Since yours doesn't stabilize until 195F, it has a "capacity" problem...it can't reject as much heat as it should. But, since it doesn't overheat with the stat removed, you can get away with it. I assure you that, over time, that temp will get higher. Your first option would be to put some radiator cleaner through the system to rid it of collected scale and corrosion on the inside of the radiator; just flushing the radiator will not get that job done. That, alone, may solve your problem. Once you get it to where the engine will stabilize at something below 175F [or less], you can install the 180 (or higher) stat again.

 

So does disabling vacuum advance the way Chevy did with the TCS system.

cc

 

AW, do you have any radiator specialty shops in your area? You might want to talk to them about boiling the radiator out and checking it's capacity.

cc

 

Ok guys it's fixed and the NAPA guy, (Kid) was right. I changed nothing and hooked up the expansion tank so that the system could pressurize. I guess to be picky there was a change, I needed to add maybe a quart to fill the tank 3/4 of the way. So without the stat it stabilized and ran for at least a half hour at about 160. Then I shut it down and put the 180 stat back in and it stabilized at what I would say was 175. Hard to tell with that little gauge. So the 15psi of pressure made all the difference in the world. My new 383 with the original 40 year old radiator is running at normal temps. BUT, will it run hotter when the body is on and I have it under load driving it? TBD. Thanks for all the help. It keeps the ideas going until the solution somehow pops up.