Additional electric cooling fan in front of rad?
Super Moderator
Joined: Jan 2011
Posts: 16,322
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From: Savannah Georgia
Indeed.
Compensating for lack of maintenace is one set of problems, and depending on the information from a mechanical device, monitored elsewhere in the coolant stream by an analog device, converted to precise computer controlled pulse width modulated square wave, to drive an analog display needle at 9:00 within values of "X" and "Y" established by a programmer - only adds to the confusion. I believe Rover would have saved a lot of repairs if the space between 9:00 and end of scale was another color, like orange, to alert owners that temps were above where Rover planned for them to be.
I worry about owners driving about at 10:00 or so, thinking that is just a little warm, etc. When it is actually equal to (max allowable normal temp) + (extra temp represented by change from 9:00 to current position).
And as a newbie, I took on my D1, which had these problems all when I bought it:
1. Fan belt route wrong. Re-routed.
2. Fan clutch worn out - free wheeling. Fan would STOP when AC was turned on. Replaced clutch with one from Chevy write up.
3. Electric fans reverse wired - would subtract enough air to STOP main fan with bad clutch. Reversed wires to "normal"
4. Radiator clogged with calcium and stop leak. Rodded out and acid boiled out.
5. Water pump wobbling. Replaced pump.
And that was just the start....
Compensating for lack of maintenace is one set of problems, and depending on the information from a mechanical device, monitored elsewhere in the coolant stream by an analog device, converted to precise computer controlled pulse width modulated square wave, to drive an analog display needle at 9:00 within values of "X" and "Y" established by a programmer - only adds to the confusion. I believe Rover would have saved a lot of repairs if the space between 9:00 and end of scale was another color, like orange, to alert owners that temps were above where Rover planned for them to be.
I worry about owners driving about at 10:00 or so, thinking that is just a little warm, etc. When it is actually equal to (max allowable normal temp) + (extra temp represented by change from 9:00 to current position).
And as a newbie, I took on my D1, which had these problems all when I bought it:
1. Fan belt route wrong. Re-routed.
2. Fan clutch worn out - free wheeling. Fan would STOP when AC was turned on. Replaced clutch with one from Chevy write up.
3. Electric fans reverse wired - would subtract enough air to STOP main fan with bad clutch. Reversed wires to "normal"
4. Radiator clogged with calcium and stop leak. Rodded out and acid boiled out.
5. Water pump wobbling. Replaced pump.
And that was just the start....
Last edited by Savannah Buzz; Nov 25, 2011 at 10:25 PM.
Thread Starter
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Rock Crawling
Joined: Sep 2011
Posts: 330
Likes: 22
sickws6:
Glad you asked....
The "old school" water pump operated fan clutch moves on the order of 900 - 1100 feet per minute of air speed thru the radiator "sandwich" of Ac condenser, stack of tranny cooler and oil cooler (if so equipped) and the two section 45 row aluminum coolant radiator. Now at 60 mph, you are moving 5280 feet per minute of air thru there (you can do the math to convert to cubic feet per minute).
The existing system has a viscous clutch, which is reverse rotation, six inch, and is the same size used by lots of GM and Chevy trucks. A stock clutch de-couples after initial spin up to about 20% coupling, and re-couples slowly (like a variable speed drill) to about 60% coupling after faceplate reaches 170 F. You can buy aftermarket heavy duty clutch that will couple at 75 - 90%. De-coupled they provide MPG boost in nomal conditions.
You can also change your pitch on the fan to move a little more air. The plus of that is that it also increases air flow while driving, and the effect can be noticed in hot weather. Pix of Chevy 2001 Blazer fan and clutch installed on my D1 at test, $20 investment from junkyard. You may not have Disco's in nearby junkyard, but Chevy's are pretty common.
Now as to your overheating in traffic:
1. Let us define "overheat" for the D2. The D2 uses an engine coolant temp sensor, and monitors it with the ECU. The ECU outputs a PWM signal (pulse-width modulated) to drive the display gauge. It is driven to show 9:00 position for normal (defined by Rover) temperature. In the RAVE, you will find this text about the gauge:
path to illuminate the high coolant temperature warning lamp.
2. So if your temp gauge is above 9:00 position, by definition, you are overheating.
3. The thermostat is described in the RAVE:
warm-up. The thermostat is closed at temperatures below approximately 82
Glad you asked....
The "old school" water pump operated fan clutch moves on the order of 900 - 1100 feet per minute of air speed thru the radiator "sandwich" of Ac condenser, stack of tranny cooler and oil cooler (if so equipped) and the two section 45 row aluminum coolant radiator. Now at 60 mph, you are moving 5280 feet per minute of air thru there (you can do the math to convert to cubic feet per minute).
The existing system has a viscous clutch, which is reverse rotation, six inch, and is the same size used by lots of GM and Chevy trucks. A stock clutch de-couples after initial spin up to about 20% coupling, and re-couples slowly (like a variable speed drill) to about 60% coupling after faceplate reaches 170 F. You can buy aftermarket heavy duty clutch that will couple at 75 - 90%. De-coupled they provide MPG boost in nomal conditions.
You can also change your pitch on the fan to move a little more air. The plus of that is that it also increases air flow while driving, and the effect can be noticed in hot weather. Pix of Chevy 2001 Blazer fan and clutch installed on my D1 at test, $20 investment from junkyard. You may not have Disco's in nearby junkyard, but Chevy's are pretty common.
Now as to your overheating in traffic:
1. Let us define "overheat" for the D2. The D2 uses an engine coolant temp sensor, and monitors it with the ECU. The ECU outputs a PWM signal (pulse-width modulated) to drive the display gauge. It is driven to show 9:00 position for normal (defined by Rover) temperature. In the RAVE, you will find this text about the gauge:
The engine coolant temperature gauge is an analogue gauge with three sections: cold temperature; normal operating
temperature; high temperature. Under normal engine operating temperatures the engine coolant temperature gauge
will display in the centre of the gauge. When the engine is cold e.g. from first start-up, the coolant temperature gauge
will display in the cold band. When the engine is over heating the temperature gauge will display in the high
temperature band. If the engine coolant temperature gauge receives no input or the input is out of range the
temperature gauge will read cold and the high coolant temperature warning lamp will be illuminated.
The input signal is a PWM signal from the engine coolant temperature sensor via the ECM. The power input for the
high coolant temperature warning lamp is supplied by the instrument pack via fuse 27. The ECM controls the earth
temperature; high temperature. Under normal engine operating temperatures the engine coolant temperature gauge
will display in the centre of the gauge. When the engine is cold e.g. from first start-up, the coolant temperature gauge
will display in the cold band. When the engine is over heating the temperature gauge will display in the high
temperature band. If the engine coolant temperature gauge receives no input or the input is out of range the
temperature gauge will read cold and the high coolant temperature warning lamp will be illuminated.
The input signal is a PWM signal from the engine coolant temperature sensor via the ECM. The power input for the
high coolant temperature warning lamp is supplied by the instrument pack via fuse 27. The ECM controls the earth
path to illuminate the high coolant temperature warning lamp.
2. So if your temp gauge is above 9:00 position, by definition, you are overheating.
3. The thermostat is described in the RAVE:
The thermostat is used to maintain the coolant at the optimum temperature for efficient combustion and to aid engine
warm-up. The thermostat is closed at temperatures below approximately 82
°C (179°F). When the coolant
temperature reaches approximately 82
°C the thermostat starts to open and is fully open at approximately 96°C
(204
°F). In this condition the full flow of coolant is directed through the radiator.
So, if you are using a scanner or Ultra Gauge, you can get real time data degree by degree, same as the ECU. If coolant temp is well ABOVE 204 F, stat is no longer controlling system. For rule of thumb, my D1 with a stock 195 stat goes down the road at 50 mph at 194-196 F. This is an important baseline, what kind of cooling performance you get at roadway speed. I would expect a healthy D2 could have roadway speed temps in the 190 - 200 F range. If the roadway temp is always 206 - 210, what is making it warm?
4. The stat uses 4 metering holes to circulate hot coolant back to activate the stat (make it open). If those holes are clogged, stat will take longer to open (and block temp goes higher). In addition, if the stat is open/closing as it would in average temp normal operation, the flow thru the stat will be cut off or sharply reduced. During that time coolant is still circulating thru the ALWAYS flowing heater core. If heater core is clogged, that could impact flow in the cooling system, and again shift the operating point of the stat upward.
5. Radiator and horizontal section of stat provide great place to accumulate crud, dexcool sludge, previous owner stopz leekz, etc. This can restrict bottom tubes of the radiator, reducing the cooling capacity. Raditor will be much colder on bottom than top. My indy rad guy says about 10 degrees F spread top to bottom on healthy radiator. Test with hand or IR thermometer. Converting from Dexcool may take more than a 5 minute flush, and new green coolant added to sludge remaining after a flush could cause problems. GM tech note calls for several hours of running with flush in engine.
6. So in summary, you may have additional problems causing extra warm temps. Putting on a bigger fan just hides them. Now the D1 has two fans, and a bone head PO wired mine reverse polarity, so they subtracted air flow and really overheated at idle. The D1 runs fans all the time when AC is on, the D2 adds some brains and only runs when it needs it.
From the RAVE:
The thermostat is exposed to 90% hot coolant from the engine on one side and 10% cold coolant returning from the
radiator bottom hose on the other side.
Hot coolant from the engine passes from the by-pass pipe through four sensing holes in the flow valve into a tube
surrounding 90% of the thermostat sensitive area. Cold coolant returning from the engine, cooled by the radiator,
conducts through 10% of the sensitive area.radiator bottom hose on the other side.
Hot coolant from the engine passes from the by-pass pipe through four sensing holes in the flow valve into a tube
surrounding 90% of the thermostat sensitive area. Cold coolant returning from the engine, cooled by the radiator,
So, if you are using a scanner or Ultra Gauge, you can get real time data degree by degree, same as the ECU. If coolant temp is well ABOVE 204 F, stat is no longer controlling system. For rule of thumb, my D1 with a stock 195 stat goes down the road at 50 mph at 194-196 F. This is an important baseline, what kind of cooling performance you get at roadway speed. I would expect a healthy D2 could have roadway speed temps in the 190 - 200 F range. If the roadway temp is always 206 - 210, what is making it warm?
4. The stat uses 4 metering holes to circulate hot coolant back to activate the stat (make it open). If those holes are clogged, stat will take longer to open (and block temp goes higher). In addition, if the stat is open/closing as it would in average temp normal operation, the flow thru the stat will be cut off or sharply reduced. During that time coolant is still circulating thru the ALWAYS flowing heater core. If heater core is clogged, that could impact flow in the cooling system, and again shift the operating point of the stat upward.
5. Radiator and horizontal section of stat provide great place to accumulate crud, dexcool sludge, previous owner stopz leekz, etc. This can restrict bottom tubes of the radiator, reducing the cooling capacity. Raditor will be much colder on bottom than top. My indy rad guy says about 10 degrees F spread top to bottom on healthy radiator. Test with hand or IR thermometer. Converting from Dexcool may take more than a 5 minute flush, and new green coolant added to sludge remaining after a flush could cause problems. GM tech note calls for several hours of running with flush in engine.
6. So in summary, you may have additional problems causing extra warm temps. Putting on a bigger fan just hides them. Now the D1 has two fans, and a bone head PO wired mine reverse polarity, so they subtracted air flow and really overheated at idle. The D1 runs fans all the time when AC is on, the D2 adds some brains and only runs when it needs it.
From the RAVE:
While the A/C system is on, operation of the electric engine cooling fan, to assist refrigerant condenser operation, is
determined by a combination of vehicle speed and external air temperature. When cooling fan operation is required,
the ATC ECU outputs a cooling fan request to the ECM, which then energises the cooling fan relay. The cooling fan
request is output if vehicle speed is 80 km/h or less while the external air temperature is 28
determined by a combination of vehicle speed and external air temperature. When cooling fan operation is required,
the ATC ECU outputs a cooling fan request to the ECM, which then energises the cooling fan relay. The cooling fan
request is output if vehicle speed is 80 km/h or less while the external air temperature is 28
°C (82 °F) or more. The
The electric fan also comes on when coolant is 212F, and drops off when coolant reaches 202F, back under thermostat control (General Data section)
You need to know real numbers, not just relative position of the "gauge" which is actually a warning light with a pointer. Ultra Gauge pix attached, it allows you to program alarm points, etc. Around $80.
You need to be sure you are not suffering from dexcool sludge. Will send GM info in next post. You need to examine thermostat, and replace if needed. Since members are routinely able to navigate in Death Valley, the Mojave, and similar areas around the world, your traffic jam should not be much of a challenge. Would not think you are the only urban operator of a Discovery 2. A sludged radiator looks the same on the outside as a good condition one. An indy shop may be able to hot flush with a formula that is OK for aluminum radiators. Don't try the old school muriatic acid at home on aluminum. You might consider adding some watter wetter or purple ice to increase cooling slightly, these work by being a "wetting agent" (soap) that makes the bubbles formed even smaller.
Speaking of bubbles - any water flow noise under the dash? Coolant loss, over heating spikes, white smoke from exhaust? You could have a head gasket problem. There is a chemical test you can buy ($35 - 50) that will do about 16 tests for cobustion gas in coolant.
7. Once you get the basics right, if you want to experiment, great. There is a system of alterations that allows you to eliminate the Rover thermostat and replace it with a GM 180 degree one at the end of the hose. But if you have other problems (HG, clogged radiator, wimpy water pump, etc.) - you will find that no stat (145 F), 160 F stat, or 180 Stat will all have temperature higher, because the base problem has not been fixed. The stat only controls how COLD the coolant stays. When you add other heat producing (AC condenser, auto tranny, engine at high rpm / low speed (rock crawling)) issues to an under performing cooling system, you will have a temp increase. Do it long enough and you will have fried Disco.
8. You can buy after market water pumps that have increase flow, like from British Pacific.
9. You can use the "search" feature to find lots more about this. You can also download your very own copy of the RAVE.
request is cancelled, and the cooling fan switched off, if either the vehicle speed increases to 100 km/h, or the external
air temperature decreases to 25 °C (77 °F).The electric fan also comes on when coolant is 212F, and drops off when coolant reaches 202F, back under thermostat control (General Data section)
You need to know real numbers, not just relative position of the "gauge" which is actually a warning light with a pointer. Ultra Gauge pix attached, it allows you to program alarm points, etc. Around $80.
You need to be sure you are not suffering from dexcool sludge. Will send GM info in next post. You need to examine thermostat, and replace if needed. Since members are routinely able to navigate in Death Valley, the Mojave, and similar areas around the world, your traffic jam should not be much of a challenge. Would not think you are the only urban operator of a Discovery 2. A sludged radiator looks the same on the outside as a good condition one. An indy shop may be able to hot flush with a formula that is OK for aluminum radiators. Don't try the old school muriatic acid at home on aluminum. You might consider adding some watter wetter or purple ice to increase cooling slightly, these work by being a "wetting agent" (soap) that makes the bubbles formed even smaller.
Speaking of bubbles - any water flow noise under the dash? Coolant loss, over heating spikes, white smoke from exhaust? You could have a head gasket problem. There is a chemical test you can buy ($35 - 50) that will do about 16 tests for cobustion gas in coolant.
7. Once you get the basics right, if you want to experiment, great. There is a system of alterations that allows you to eliminate the Rover thermostat and replace it with a GM 180 degree one at the end of the hose. But if you have other problems (HG, clogged radiator, wimpy water pump, etc.) - you will find that no stat (145 F), 160 F stat, or 180 Stat will all have temperature higher, because the base problem has not been fixed. The stat only controls how COLD the coolant stays. When you add other heat producing (AC condenser, auto tranny, engine at high rpm / low speed (rock crawling)) issues to an under performing cooling system, you will have a temp increase. Do it long enough and you will have fried Disco.
8. You can buy after market water pumps that have increase flow, like from British Pacific.
9. You can use the "search" feature to find lots more about this. You can also download your very own copy of the RAVE.
You are awesome my friend. I have obd2link with app rev on my itouch, temps have been steady around 206-209, and it doesn't take long to get that high. Thank you so much for all the great information in your post. I will be replacing the thermostat and the rad looks like no crud build up but may as well take it out and blow/hose it off real well.
Please bare with me guys as i just purchased this thing and I am getting nervous because I have that tick after it warms up a bit, which I read may be slipped sleeves.
So it is a bad thing to run cooler than "operating temperature"? What is the downfall to running cool other than you may not get great heat? Or unless maybe all of the tolerances of the engine were designed for a specific temp range? I always thought the cooler you are the safer you are.
And yes I understand maintenance is important to sustain good and normal operation of any system on any car, but usually these forums arise from people who all have similar issues with their similar cars. I apologize for my ignorance to these vehicles as I am learning. I have done plenty of searches and really found some interesting things about these vehicles.
So I will conduct the common maintenance as mentioned above and let you all know how it went.
Thread Starter
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Rock Crawling
Joined: Sep 2011
Posts: 330
Likes: 22
The technical reason is that the Discovery cooling system, when in good condition, will keep the Discovery engine at correct operating temperature. If it's over heating, even in slow/stop and go traffic/off-roading, then there is a fault in the system.
Adding an additional fan because your cooling systems isn't in good repair would be like installing a 60amp fuse because your 30amp fuel pump fuse keeps blowing.
Adding an additional fan because your cooling systems isn't in good repair would be like installing a 60amp fuse because your 30amp fuel pump fuse keeps blowing.
You are awesome my friend. I have obd2link with app rev on my itouch, temps have been steady around 206-209, and it doesn't take long to get that high. Thank you so much for all the great information in your post. I will be replacing the thermostat and the rad looks like no crud build up but may as well take it out and blow/hose it off real well.
Please bare with me guys as i just purchased this thing and I am getting nervous because I have that tick after it warms up a bit, which I read may be slipped sleeves.
So it is a bad thing to run cooler than "operating temperature"? What is the downfall to running cool other than you may not get great heat? Or unless maybe all of the tolerances of the engine were designed for a specific temp range? I always thought the cooler you are the safer you are.
And yes I understand maintenance is important to sustain good and normal operation of any system on any car, but usually these forums arise from people who all have similar issues with their similar cars. I apologize for my ignorance to these vehicles as I am learning. I have done plenty of searches and really found some interesting things about these vehicles.
So I will conduct the common maintenance as mentioned above and let you all know how it went.
Please bare with me guys as i just purchased this thing and I am getting nervous because I have that tick after it warms up a bit, which I read may be slipped sleeves.
So it is a bad thing to run cooler than "operating temperature"? What is the downfall to running cool other than you may not get great heat? Or unless maybe all of the tolerances of the engine were designed for a specific temp range? I always thought the cooler you are the safer you are.
And yes I understand maintenance is important to sustain good and normal operation of any system on any car, but usually these forums arise from people who all have similar issues with their similar cars. I apologize for my ignorance to these vehicles as I am learning. I have done plenty of searches and really found some interesting things about these vehicles.
So I will conduct the common maintenance as mentioned above and let you all know how it went.
Running to cold will reduce MPG, increase emissions and wear out your cat's sooner.
Running to cold will also decrease motor oil life, so will running to hot.
190-210 is the optimal operating range for this engine.
Super Moderator
Joined: Jan 2011
Posts: 16,322
Likes: 88
From: Savannah Georgia
Tick can be slipped sleeve, which is bad. But it can also be:
Oil pump cracked (check with mechanical PSI test) if low PSI, engine wear from this is much more severe than five degrees warmer coolant temp than you might like. If you are excited about coolant temp, wait until you see oil PSI....
Flex plate cracked (couples tranny to flywheel)
SAI component(s)
So search completely.
Oil pump cracked (check with mechanical PSI test) if low PSI, engine wear from this is much more severe than five degrees warmer coolant temp than you might like. If you are excited about coolant temp, wait until you see oil PSI....
Flex plate cracked (couples tranny to flywheel)
SAI component(s)
So search completely.
Baja
Joined: Sep 2007
Posts: 5,232
Likes: 52
From: Georgia, USA
That's because there is no technical reason not to do it, which is what you were asking for, other than the fact it's a waste of time, money and effort and is not needed if your cooling system is in good repair.
Now, if you wanted to know how to diagnose a faulty cooling system, that's a different question and completely separate from installing an electric fan to "improve" a system that works fine.
Now, if you wanted to know how to diagnose a faulty cooling system, that's a different question and completely separate from installing an electric fan to "improve" a system that works fine.
Before you go tearing the engine apart what oil are you using?
Anything w-30 is to thin for these engines.
Not knowing where you live makes it harder to recommend a oil for you.
I live in MI, it gets cold here in the winter, I use Shell Rotella 5w-40 in the winter and 15w-40 in the summer.
To thin of a oil can cause engine noises.
Anything w-30 is to thin for these engines.
Not knowing where you live makes it harder to recommend a oil for you.
I live in MI, it gets cold here in the winter, I use Shell Rotella 5w-40 in the winter and 15w-40 in the summer.
To thin of a oil can cause engine noises.