thermostat
Seasoned Member
Joined: Aug 2011
Posts: 344
Likes: 1
From: California
Year: 1989
Model: Cherokee
Engine: 4.0 i6
Another great post 
. if the water is flowing too fast through the system it will not have time to absorb the heat from the cast iron engine block and cylinder head. What you see on the temp gauge is the WATER temp, not the actual engine temp. Think of it this way, you can touch a hot frying pan quickly without getting burned because you hand was not there long enough to absorb too much heat. Now rest your hand on a hot frying pan for five seconds and see what happens, your hand absorbed more heat and you got burned. It works the same way with a cooling system, the water needs time to absorb heat before it flows to the radiator. A cooling system with a high anti-freeze to water ratio will run hotter too because the anti-freeze/coolant does not absorb heat as fast as water.
. if the water is flowing too fast through the system it will not have time to absorb the heat from the cast iron engine block and cylinder head. What you see on the temp gauge is the WATER temp, not the actual engine temp. Think of it this way, you can touch a hot frying pan quickly without getting burned because you hand was not there long enough to absorb too much heat. Now rest your hand on a hot frying pan for five seconds and see what happens, your hand absorbed more heat and you got burned. It works the same way with a cooling system, the water needs time to absorb heat before it flows to the radiator. A cooling system with a high anti-freeze to water ratio will run hotter too because the anti-freeze/coolant does not absorb heat as fast as water.Coolant boils at a higher rate than water.
Simple and clear, if you have more water in your system, it will boil at 212
If you have 50/50 coolant/water ratio the system will boil at 265 depending where you live at elavations above 3,000 ft above sea level.
I am always above 3,000 all the way to 7,500, and sometimes go down to L.A. and SFV.
So...if the coolant you add keeps the water from boiling at it's normal temp of 212 then that means it takes longer to heat up, and it stays cooler.
Last edited by BigBear; Jul 6, 2012 at 06:43 PM.
Seasoned Member
Joined: Aug 2011
Posts: 344
Likes: 1
From: California
Year: 1989
Model: Cherokee
Engine: 4.0 i6
Mine was stuck on the original one and I saw this image and I copied it a little with the barb on top of a 6" copper pipe.
Update I just found and bought the original water pump inlet tube.
Last edited by BigBear; Jul 6, 2012 at 06:44 PM.
CF Veteran
Joined: Feb 2010
Posts: 12,367
Likes: 23
From: Oroville, CA
Year: 1995
Model: Grand Cherokee
Engine: 4.0 with all of the noise and clatter
Coolant boils at a higher rate than water.
Simple and clear, if you have more water in your system, it will boil at 160
If you have 50/50 coolant/water ratio the system will boil at 265 depending where you live at elavations above 3,000 ft above sea level.
I am always above 3,000 all the way to 7,500, and sometimes go down to L.A. and SFV.
So...if the coolant you add keeps the water from boiling at it's normal temp of 160 then that means it takes longer to heat up, and it stays cooler.
Simple and clear, if you have more water in your system, it will boil at 160
If you have 50/50 coolant/water ratio the system will boil at 265 depending where you live at elavations above 3,000 ft above sea level.
I am always above 3,000 all the way to 7,500, and sometimes go down to L.A. and SFV.
So...if the coolant you add keeps the water from boiling at it's normal temp of 160 then that means it takes longer to heat up, and it stays cooler.
Last edited by Bustedback; Aug 17, 2011 at 02:32 PM.
Senior Member
Joined: Aug 2011
Posts: 760
Likes: 6
From: Landers, CA
Year: Several
Model: Cherokee
Engine: 4.0
""""" The ECU/PCM is looking for the O2 info so the motor can run clean/lean (closed loop) well before coolant temp is anywhere close to normal average operating range. Why wait 10 mins to run clean/lean (waiting on coolant temp) when it can run clean/lean within seconds of start-up?"""""
So you think the only input to the PCM is from the O2 sensor(s)?
What happened to Throttle Position, load (MAP,) RPM etc?
Temperature doesn't even enter into it?
I'd suggest you get a good scanner system hooked into your laptop - then you can see all the inputs and see how they ALL influence the PCM.
So you think the only input to the PCM is from the O2 sensor(s)?
What happened to Throttle Position, load (MAP,) RPM etc?
Temperature doesn't even enter into it?
I'd suggest you get a good scanner system hooked into your laptop - then you can see all the inputs and see how they ALL influence the PCM.
Thread Starter
Junior Member
Joined: Aug 2011
Posts: 89
Likes: 0
Well I got the new water pump all hooked up, it still doesn't run right. Next is to check the radiator.
When the a/c is on and its running it squeals and wont stop, I tightened the serp. Down and it still is squealing like a ****. Should I tighten it down even more? Get a new belt?
It seemed to get hotter quicker, and it was at night.
When the a/c is on and its running it squeals and wont stop, I tightened the serp. Down and it still is squealing like a ****. Should I tighten it down even more? Get a new belt?
It seemed to get hotter quicker, and it was at night.
Senior Member
Joined: Aug 2011
Posts: 760
Likes: 6
From: Landers, CA
Year: Several
Model: Cherokee
Engine: 4.0
Use a short piece of hose- heater hose, garden hose etc to listen through like a stethoscope - try to find what is squealing. could be an idler pulley locking up, even the AC compressor.
Engine off, try twisting the serp belt with your fingers- if the tension is right you should be able to twist it 1/4 turn - 90 degrees with effort.
more is too loose, less is too tight.
Engine off, try twisting the serp belt with your fingers- if the tension is right you should be able to twist it 1/4 turn - 90 degrees with effort.
more is too loose, less is too tight.
Member
Joined: May 2011
Posts: 167
Likes: 0
From: Charleston SC
Year: 2000
Model: Cherokee
Engine: 4.0L
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
""""" The ECU/PCM is looking for the O2 info so the motor can run clean/lean (closed loop) well before coolant temp is anywhere close to normal average operating range. Why wait 10 mins to run clean/lean (waiting on coolant temp) when it can run clean/lean within seconds of start-up?"""""
So you think the only input to the PCM is from the O2 sensor(s)?
What happened to Throttle Position, load (MAP,) RPM etc?
Temperature doesn't even enter into it?
I'd suggest you get a good scanner system hooked into your laptop - then you can see all the inputs and see how they ALL influence the PCM.
So you think the only input to the PCM is from the O2 sensor(s)?
What happened to Throttle Position, load (MAP,) RPM etc?
Temperature doesn't even enter into it?
I'd suggest you get a good scanner system hooked into your laptop - then you can see all the inputs and see how they ALL influence the PCM.
Seasoned Member
Joined: Aug 2011
Posts: 344
Likes: 1
From: California
Year: 1989
Model: Cherokee
Engine: 4.0 i6
Temperature
Sea Level
212 degrees F
984 ft.
210 degrees F
2,000 ft.
208 degrees F
3,000 ft.
206 degrees F
5,000 ft.
203 degrees F
7,500 ft.
198 degrees F
10,000 ft.
194 degrees F
20,000 ft.
178 degrees F
26,000 ft.
168 degrees F
High Altitude: Water boils at less than 212°F (approximately 96°F). Each 500 foot increase in altitude causes a drop of about 1° in the boiling point.
Sea Level: Water boils at 212°F and simmers at 190°F.
Tepid Water - 85 to 105°F. The water is comparable to the temperature of the human body.
Warm Water - 115 to 120°F. The water is touchable but not hot.
Hot Water - 130 to 135°F. The water is too hot to touch without injury. Poach - 160 to 180°F. The water is beginning to move, to shiver.
Simmer - 185 to 200°F. There is movement, and little bubbles appear in the water.
Slow boil - 205°F. There is more movement and noticeably larger bubbles.
Real boil - 212°F. The water is rolling, vigorously bubbling, and steaming.
So if your Jeep runs at 210F your coolant is not goin to be cool enough to keep your engine cool.
With normal driving conditions you should not hear boiling water in your engine at all.
Warm Water - 115 to 120°F. The water is touchable but not hot.
Hot Water - 130 to 135°F. The water is too hot to touch without injury. Poach - 160 to 180°F. The water is beginning to move, to shiver.
Simmer - 185 to 200°F. There is movement, and little bubbles appear in the water.
Slow boil - 205°F. There is more movement and noticeably larger bubbles.
Real boil - 212°F. The water is rolling, vigorously bubbling, and steaming.
So if your Jeep runs at 210F your coolant is not goin to be cool enough to keep your engine cool.
With normal driving conditions you should not hear boiling water in your engine at all.
Member
Joined: Aug 2011
Posts: 109
Likes: 1
From: Western Montana
Year: 1991
Model: Cherokee
Engine: 4.0L HO
Coolant boils at a higher rate than water.
Simple and clear, if you have more water in your system, it will boil at 160
If you have 50/50 coolant/water ratio the system will boil at 265 depending where you live at elavations above 3,000 ft above sea level.
I am always above 3,000 all the way to 7,500, and sometimes go down to L.A. and SFV.
So...if the coolant you add keeps the water from boiling at it's normal temp of 160 then that means it takes longer to heat up, and it stays cooler.
Simple and clear, if you have more water in your system, it will boil at 160
If you have 50/50 coolant/water ratio the system will boil at 265 depending where you live at elavations above 3,000 ft above sea level.
I am always above 3,000 all the way to 7,500, and sometimes go down to L.A. and SFV.
So...if the coolant you add keeps the water from boiling at it's normal temp of 160 then that means it takes longer to heat up, and it stays cooler.
Member
Joined: May 2011
Posts: 167
Likes: 0
From: Charleston SC
Year: 2000
Model: Cherokee
Engine: 4.0L
Originally Posted by BigBear;
With normal driving conditions you should not hear boiling water in your engine at all.
Member
Joined: Aug 2011
Posts: 109
Likes: 1
From: Western Montana
Year: 1991
Model: Cherokee
Engine: 4.0L HO
- yes -
Last edited by montanaman; Aug 18, 2011 at 12:43 PM.
CF Veteran
Joined: Feb 2010
Posts: 12,367
Likes: 23
From: Oroville, CA
Year: 1995
Model: Grand Cherokee
Engine: 4.0 with all of the noise and clatter
Altitude
Temperature
Sea Level
212 degrees F
984 ft.
210 degrees F
2,000 ft.
208 degrees F
3,000 ft.
206 degrees F
5,000 ft.
203 degrees F
7,500 ft.
198 degrees F
10,000 ft.
194 degrees F
20,000 ft.
178 degrees F
26,000 ft.
168 degrees F
High Altitude: Water boils at less than 212°F (approximately 96°F). Each 500 foot increase in altitude causes a drop of about 1° in the boiling point.
Sea Level: Water boils at 212°F and simmers at 190°F.
Temperature
Sea Level
212 degrees F
984 ft.
210 degrees F
2,000 ft.
208 degrees F
3,000 ft.
206 degrees F
5,000 ft.
203 degrees F
7,500 ft.
198 degrees F
10,000 ft.
194 degrees F
20,000 ft.
178 degrees F
26,000 ft.
168 degrees F
High Altitude: Water boils at less than 212°F (approximately 96°F). Each 500 foot increase in altitude causes a drop of about 1° in the boiling point.
Sea Level: Water boils at 212°F and simmers at 190°F.
Tepid Water - 85 to 105°F. The water is comparable to the temperature of the human body.
Warm Water - 115 to 120°F. The water is touchable but not hot.
Hot Water - 130 to 135°F. The water is too hot to touch
Warm Water - 115 to 120°F. The water is touchable but not hot.
Hot Water - 130 to 135°F. The water is too hot to touch
Member
Joined: Aug 2011
Posts: 109
Likes: 1
From: Western Montana
Year: 1991
Model: Cherokee
Engine: 4.0L HO
Edit ... sorry for the double post ... my mistake
Member
Joined: May 2011
Posts: 167
Likes: 0
From: Charleston SC
Year: 2000
Model: Cherokee
Engine: 4.0L
Right - but in your cooling system at 16Psi it's 268 degrees as Montanaman said...it makes no difference whether you are in South Carolina or Colorado - inside your cooling system is a 'sealed' environment operating at up to 16 PSI the same everywhere.