Additional electric cooling fan in front of rad?
#1
11-24-2011, 07:53 PM
Additional electric cooling fan in front of rad?
I have a plan. I want to purchase a 12" electric thin fan and place it in front of the radiator to help push additional air directly through the radiator. I do not believe i like the set up from the factory with the AC/cooling fan. I plan on hooking the fan up to a switch. Any thoughts? I do plan on keeping the original mechanical fan as well.
#4
11-25-2011, 09:39 AM
Administrator
#5
11-25-2011, 09:58 AM
Baja
#6
11-25-2011, 05:11 PM
There is nothing wrong with the factory system. Is there anything wrong with IMPROVING the system? Disco mike not sure what you are talking about, there is no fan directly in front of the radiator. I see the little dinky electric fan in front of the ac cond. and the old school fan behind the radiator that is supposed to pull air through and putting stress on the water-pump (crappy design for a modern vehicle) I am talking directly in front (attached to the radiator its self) to improve air flow through the radiator. I want to make the current system better, I drive in a lot of high traffic areas and this thing idles hot because I am not getting enough air to the radiator. I am asking for your technical support here guys. Maybe I should not do this because it could not do anything at all or maybe well harm the system. Please back up your remarks with technical descriptions so I will understand and learn. thanks.
Last edited by sickws6; 11-25-2011 at 05:17 PM.
#7
11-25-2011, 08:24 PM
I get what you are saying now.
If the clutch fan is not moving enough air replace it.
If the a/c fan is not working replace it, I think there is supposed to be 2 of them anyway, there is on the DI but I am not 100% sure on the DII.
Rinse the dust, pollen, etc. off the fins of the a/c condenser and the radiator.
Make sure there is not 6" of crap built up between the a/c condenser and the radiator, this is a common place for debris to collect and it will reduce engine cooling.
Do a complete cooling system flush, Dex-Cool is known to sludge up and cause reduced engine cooling from clogging the radiator.
Replace your thermostat.
Personally I dont think another fan between the a/c condenser and radiator is going to help.
I think it is just going to get in the way and reduce air flow.
The DII cooling system sucks.
If the clutch fan is not moving enough air replace it.
If the a/c fan is not working replace it, I think there is supposed to be 2 of them anyway, there is on the DI but I am not 100% sure on the DII.
Rinse the dust, pollen, etc. off the fins of the a/c condenser and the radiator.
Make sure there is not 6" of crap built up between the a/c condenser and the radiator, this is a common place for debris to collect and it will reduce engine cooling.
Do a complete cooling system flush, Dex-Cool is known to sludge up and cause reduced engine cooling from clogging the radiator.
Replace your thermostat.
Personally I dont think another fan between the a/c condenser and radiator is going to help.
I think it is just going to get in the way and reduce air flow.
The DII cooling system sucks.
#8
11-25-2011, 08:31 PM
Baja
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.
#9
11-25-2011, 09:18 PM
Super Moderator
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.
Last edited by Savannah Buzz; 11-25-2011 at 09:22 PM.
#10
11-25-2011, 09:21 PM
Super Moderator
Additional back ground photos and GM dexcool flush method - note that it takes more than 15 minutes. With respect to stat temperature, many of us stalk the salvage yards and it is not uncommon to find a Disco with no thermostat, an attempt by PO to keep running with bad head gaskets or slipped sleeve, erosion behind the sleeve, cracked block. The truck still made it to the salvage yard. You need a stat in summer to control how long coolant stays in the radiator to cool down.
Last edited by Savannah Buzz; 11-25-2011 at 09:26 PM.