Overcooling????
Thread Starter
|
Senior User
Joined: Jan 2002
Posts: 167
Likes: 0
From: Kansas
Overcooling????
The local raditor shop said it was a flow problem, quickly followed by the price of a new radiator he had for my truck, so I'm not considering that a totally reliable, unbiased answer. When I did the same test with my cold-running truck (same engine), it didn't overflow, or even noticably rise, but there was steam coming out the neck and the top hose was warm, so it seemed to be working just fine. Worst case scenireo, I'm planning to replace the replaceable parts of the cooling system. If it works, problem solved. If it doesn't, I'll know that it's something else, and won't have to replace them again later.
Matt
Matt
Thread Starter
|
Senior User
Joined: Jan 2002
Posts: 167
Likes: 0
From: Kansas
Overcooling????
Hi, all. Just me and my dead horse here. Anyone care to join me in a swing?
Okay, I picked up a copy of Steve Christ's "How to Rebuild Ford Big-Block Engines" that a local bookstore was very kind in ordering for me. In this book, on the upper-left corner of a left page, there is a graph, with a parabolic (I think...complex math classes were many moons ago) curve showing the relative wear, in inches, associated with running an engine too cold.
At 160, there is more wear than at 200, as everyone has said. It is also such a neglegible amount more that, in the few miles I have put on this engine (less than 20k), I don't think I have caused much of a problem, as everyone has said.
I just thought I'd add some in-print data to support everyone who added their two cents, and thank the forum at large for being a huge source of data.
Matt
Okay, I picked up a copy of Steve Christ's "How to Rebuild Ford Big-Block Engines" that a local bookstore was very kind in ordering for me. In this book, on the upper-left corner of a left page, there is a graph, with a parabolic (I think...complex math classes were many moons ago) curve showing the relative wear, in inches, associated with running an engine too cold.
At 160, there is more wear than at 200, as everyone has said. It is also such a neglegible amount more that, in the few miles I have put on this engine (less than 20k), I don't think I have caused much of a problem, as everyone has said.
I just thought I'd add some in-print data to support everyone who added their two cents, and thank the forum at large for being a huge source of data.
Matt
New User
Joined: Nov 2002
Posts: 1
Likes: 0
Overcooling????
I agree with the responses above but before you go spending hard earned dollars replacing you system components you may want to give this theory some thought.
Cooling systems are pressurized to prevent “after boil”. Water boils at 212 degrees at atmospheric pressure. When you increase the pressure of the water (greater than atmospheric pressure) the boiling point of the water will also increase. This is the reason for pressure ratings on radiator caps. The higher the pressure rating on the cap the higher the boiling point on the system. A cooling system that is not pressurized will begin to boil @ approximately the same temperature that water boils @ atmospheric pressure, thus overflowing the expansion tank on the radiator.
:7
Saddle Man
Cooling systems are pressurized to prevent “after boil”. Water boils at 212 degrees at atmospheric pressure. When you increase the pressure of the water (greater than atmospheric pressure) the boiling point of the water will also increase. This is the reason for pressure ratings on radiator caps. The higher the pressure rating on the cap the higher the boiling point on the system. A cooling system that is not pressurized will begin to boil @ approximately the same temperature that water boils @ atmospheric pressure, thus overflowing the expansion tank on the radiator.
:7
Saddle Man
Freshman User
Joined: Nov 2002
Posts: 35
Likes: 1
From: La Grange
Overcooling????
Lots of good stuff, most posts had the right conclussions but some for the wrong reasons. To clarify..
a. Running a cooler T-stat reduces engine efficiency. How much is not quantifiable. I rember this from my IC engine classes. IC engine efficiency is limted by the materials. Make an engine from ceramics, run it hotter, and the efficiency goes up.
b. The colder the engine runs the faster the wear rate. Refering to one of my references, SBF engines by Tom Monroe, the wear at 180 DEGF is .0002 in after 60 hour test. The wear at 160 DEGF was .001 inch(5 times faster). The wear at 60DEGF was .004 inches or 20 times more than at 180 DEGF. (Data from a test ran by Continental Motors)
c. Water is non compressible. This means that it will increase in volume as tempearture goes up. The right way to fill the radiator is to leave about 1" of free air space. The air can compress and allow for the increasing water volume.
d. Engines run with out T-stats, or stuck T-stats, will be severly sludged up. This sludge clogs oil pump pick up screens and can even block of the oil flow holes in the push rods. The sludge is formed when the oil does not get hot enough to drive moisture out of the engine.
Hope this helps,
Eric
a. Running a cooler T-stat reduces engine efficiency. How much is not quantifiable. I rember this from my IC engine classes. IC engine efficiency is limted by the materials. Make an engine from ceramics, run it hotter, and the efficiency goes up.
b. The colder the engine runs the faster the wear rate. Refering to one of my references, SBF engines by Tom Monroe, the wear at 180 DEGF is .0002 in after 60 hour test. The wear at 160 DEGF was .001 inch(5 times faster). The wear at 60DEGF was .004 inches or 20 times more than at 180 DEGF. (Data from a test ran by Continental Motors)
c. Water is non compressible. This means that it will increase in volume as tempearture goes up. The right way to fill the radiator is to leave about 1" of free air space. The air can compress and allow for the increasing water volume.
d. Engines run with out T-stats, or stuck T-stats, will be severly sludged up. This sludge clogs oil pump pick up screens and can even block of the oil flow holes in the push rods. The sludge is formed when the oil does not get hot enough to drive moisture out of the engine.
Hope this helps,
Eric
Thread
Thread Starter
Forum
Replies
Last Post
Rusty_S
Cooling, Heating, Ventilation & A/C
3
Apr 30, 2010 06:06 PM
inline6/91f150
Ford Inline Six, 200, 250, 4.9L / 300
9
Jun 17, 2007 10:04 PM
josepepper
1997 - 2006 Expedition & Navigator
7
Feb 17, 2004 07:51 AM
