Fan Clutch alternatives
#1
06-16-2012, 03:25 AM
Fan Clutch alternatives
Coming home from work today my temperature started to rise above half way on the temp gauge. The electric fan came on but it couldn't bring the temperature back down. Final temperature reading was about 1 o'clock on the gauge, where 12 o'clock is in the middle of the gauge and 3 o'clock would be in the red.
Car has ran in much hotter temperature and hasn't had any overheating problems since I got it 3 years ago. Water levels are ok. No leaks. Radiator is clear (at least externally at the front around the oil cooler, etc. To test the fan clutch on the main engine fan I waited until the car had cooled down, then I turned the fan by hand (with the car turned off) The fan freely rotates....... according to what I have read, I think it is only supposed to turn 1 to 1.5 turns when cold.
Based on this my assessment is the fan clutch has gone. (at the very least)
Assuming I am right about that, I have seen others modify the main fan by removing the clutch and connecting it directly. I have also seen a twin electric fan set up which replaces the small puny existing electric fan, and also the engine fan with another electric fan (This is a product made my FasterJags, the folks that do the Growler kits)
I'd be interested to hear if you agree with my diagnosis in the first place, and also if anyone has modified the fan to a direct connection, or if anyone is running the FasterJags twin fan set up.
As is typical with my XJS, this Sunday we in the Bay Area are having a Jag meet for the first time, and I was looking forward to turning up with both cars..... looks like thats not going to happen this time, boo
Car has ran in much hotter temperature and hasn't had any overheating problems since I got it 3 years ago. Water levels are ok. No leaks. Radiator is clear (at least externally at the front around the oil cooler, etc. To test the fan clutch on the main engine fan I waited until the car had cooled down, then I turned the fan by hand (with the car turned off) The fan freely rotates....... according to what I have read, I think it is only supposed to turn 1 to 1.5 turns when cold.
Based on this my assessment is the fan clutch has gone. (at the very least)
Assuming I am right about that, I have seen others modify the main fan by removing the clutch and connecting it directly. I have also seen a twin electric fan set up which replaces the small puny existing electric fan, and also the engine fan with another electric fan (This is a product made my FasterJags, the folks that do the Growler kits)
I'd be interested to hear if you agree with my diagnosis in the first place, and also if anyone has modified the fan to a direct connection, or if anyone is running the FasterJags twin fan set up.
As is typical with my XJS, this Sunday we in the Bay Area are having a Jag meet for the first time, and I was looking forward to turning up with both cars..... looks like thats not going to happen this time, boo
#2
06-16-2012, 04:53 AM
Veteran Member
The fan clutch works on an oil viscosity, when cold it allows the fan to slip so the engine can warm up quicker, and when warm the clutch locks to force the fan to spin. Test it when the engine is hot to see if it turns freely by hand. If it does, it probably is shot.
I had a crack in the fan itself so I removed it and bought a similar sized electric fan and thermostat and wired it up to run whether the ignition was on or not. I have it set in stages with the original electric fan. The larger one comes on at a slightly lower temp and the smaller one comes on at a slightly higher temp. My engine stays nice and cool even on hot days and sitting in traffic! I think the fan cost me around $100 at Autozone.
I had a crack in the fan itself so I removed it and bought a similar sized electric fan and thermostat and wired it up to run whether the ignition was on or not. I have it set in stages with the original electric fan. The larger one comes on at a slightly lower temp and the smaller one comes on at a slightly higher temp. My engine stays nice and cool even on hot days and sitting in traffic! I think the fan cost me around $100 at Autozone.
#4
06-16-2012, 09:21 AM
Veteran Member
Sarc
I have a home made twin electric fan setup. 1 x 12 inches and 1 x 17 inches. Just able to squeeze them in; but if I did it again I would do 1 x 11 and 1 x 16 inches, for easier clearance.
They work really well, better than the standard electric plus a perfectly functioning mechanical fan, IMO. The smaller fan comes on with the aircon, 100% of the time. The larger one comes on controlled by the standard thermo switch (the one on the water pump inlet); system of wiring courtesy of G Francis. I found this is MUCH better then a separate aftermarket thermostat for the big fan. It will bring down the water temperature, after a hot run on a hot day, even when stationary in traffic.
The only thing is you need to get fans that are not too deep, or they will not fit in the space available.
By the by, a new viscous unit is not too dear, and will almost certainly be the problem with your current setup. It can be a pig to fit though. Fixing the mechanical fan solidly will hurt MPG noticeably, and make the car quite a bit more noisy.
Best of all, you get another 1 to 2 MPG.
Greg
I have a home made twin electric fan setup. 1 x 12 inches and 1 x 17 inches. Just able to squeeze them in; but if I did it again I would do 1 x 11 and 1 x 16 inches, for easier clearance.
They work really well, better than the standard electric plus a perfectly functioning mechanical fan, IMO. The smaller fan comes on with the aircon, 100% of the time. The larger one comes on controlled by the standard thermo switch (the one on the water pump inlet); system of wiring courtesy of G Francis. I found this is MUCH better then a separate aftermarket thermostat for the big fan. It will bring down the water temperature, after a hot run on a hot day, even when stationary in traffic.
The only thing is you need to get fans that are not too deep, or they will not fit in the space available.
By the by, a new viscous unit is not too dear, and will almost certainly be the problem with your current setup. It can be a pig to fit though. Fixing the mechanical fan solidly will hurt MPG noticeably, and make the car quite a bit more noisy.
Best of all, you get another 1 to 2 MPG.
Greg
Last edited by Greg in France; 06-16-2012 at 09:24 AM.
#5
06-16-2012, 01:48 PM
@Greg Edge
The temp started to creep up while I was sitting still. Normally the gauge will come to around half way, or just short of it, then the electric fan comes on and the gauge moves slightly to the left again. It would do this all day long without moving higher. If I drove away in this condition the temp would come down quite a bit as soon as I built up a bit of speed and the electric fan would turn off.
Yesterday even once I got away from the stop light queue that I had been sitting in, and even with the electric fan running constantly, the temp would not come down lower than half way... in fact it was creeping even higher.
I've been driving the car all week in 85~90 deg heat over exactly the same commute route and it's been great at holding temp until yesterday, so I class this as a sudden failure, as oppose to a gradual decline. Of course I could still be dealing with a blockage in the water system somewhere, but I'll need to get the fans back up to snuff before I can assess if I need to do anything else.
@ Greg in France and Jamey
Thanks for the fan info. I'm pretty sure I'm going to go this route. I knew there would be some disadvantage to direct coupling the fan, otherwise Jaguar would not have done the viscous coupling in the first place (although this logic doesn't always apply to everything Jaguar does!)
I am communicating with Brian from FasterJags so I think I'm going to go with his twin drop in replacement as I'm a bit lazy and my fabricating days are behind me. I'll let you know how it goes.
Have a great weekend all.
Scott
The temp started to creep up while I was sitting still. Normally the gauge will come to around half way, or just short of it, then the electric fan comes on and the gauge moves slightly to the left again. It would do this all day long without moving higher. If I drove away in this condition the temp would come down quite a bit as soon as I built up a bit of speed and the electric fan would turn off.
Yesterday even once I got away from the stop light queue that I had been sitting in, and even with the electric fan running constantly, the temp would not come down lower than half way... in fact it was creeping even higher.
I've been driving the car all week in 85~90 deg heat over exactly the same commute route and it's been great at holding temp until yesterday, so I class this as a sudden failure, as oppose to a gradual decline. Of course I could still be dealing with a blockage in the water system somewhere, but I'll need to get the fans back up to snuff before I can assess if I need to do anything else.
@ Greg in France and Jamey
Thanks for the fan info. I'm pretty sure I'm going to go this route. I knew there would be some disadvantage to direct coupling the fan, otherwise Jaguar would not have done the viscous coupling in the first place (although this logic doesn't always apply to everything Jaguar does!)
I am communicating with Brian from FasterJags so I think I'm going to go with his twin drop in replacement as I'm a bit lazy and my fabricating days are behind me. I'll let you know how it goes.
Have a great weekend all.
Scott
#6
06-16-2012, 02:26 PM
If your vehicle is overheating at stand still then you have an airflow problem. There is very little heat being produced in an idling engine with no load. So you need to look at the fan clutch and make sure there is no debris blocking airflow. As I am sure you have seen in various posts the cars are famous for collecting junk between condenser and radiator. This junk is hard to see unless you remove the radiator or at the very least the upper radiator support plate.
On the other hand if your car runs hot on the road you have a cooling system flow problem or blockage of the fins with debris.
On the other hand if your car runs hot on the road you have a cooling system flow problem or blockage of the fins with debris.
#7
06-16-2012, 02:35 PM
@Greg Edge
Yep, I've read up on the rad fin blockage issues.
I am going to remove the radiator or at least the top support bracket and have a good look and my fin blockage status today. The rad was replaced 2 years ago and the crud was cleaned out from behind the condenser at that time but I will recheck it.
Yep, I've read up on the rad fin blockage issues.
I am going to remove the radiator or at least the top support bracket and have a good look and my fin blockage status today. The rad was replaced 2 years ago and the crud was cleaned out from behind the condenser at that time but I will recheck it.
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#8
06-16-2012, 07:36 PM
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for mine, i went for 2 electric fans, using the factory shroud, bought the highest CFM that would fit the big fan, and the best CFM for the small fan.
the factory shroud is a good one,it covers the whole rear of radiator, and stands off about 1 1/2 " and i locked shut the flap vents.
i was running temps of around 190-195 F(180 stats), after fan install now 175-180F.
ambient here in day 95-100+F.
i use a standalone DIGITAL temp gage,reads in 1 degree units, sensor installed at the back of left head REAR, drilled and tapped 1/4 pipe thr.
i dont want any surprises about engine temps!
the factory shroud is a good one,it covers the whole rear of radiator, and stands off about 1 1/2 " and i locked shut the flap vents.
i was running temps of around 190-195 F(180 stats), after fan install now 175-180F.
ambient here in day 95-100+F.
i use a standalone DIGITAL temp gage,reads in 1 degree units, sensor installed at the back of left head REAR, drilled and tapped 1/4 pipe thr.
i dont want any surprises about engine temps!
#10
08-19-2012, 02:08 AM
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#17
08-28-2012, 03:39 PM
So I now have the new radiator in, and the twin electric fans working, and new thermostats....... and guess what ? It's still overheating :-(
Details :
Radiator --> New Aluminum one from fasterjags. All crud cleared out from between the condenser rad and the engine rad when I pulled the old radiator.
Fans --> mechanical fan removed. Twin electric fans and shroud fitted. Both fans are sucking, ie pulling air in through the radiator. First one is ignition live. Second one is controlled by the temp switch in the water pump housing, same way as the original electric fan was wired.
Temp switch --> Changed to a lower temperature one, switches on at 82deg C
Thermostats --> replaced with new ones. 190deg C. They have jiggle pins. Jiggle pins are at the top / 12 o'clock position. They had strange rubber rings around the outside and I had problems getting them seated and fitted...... I've ordered another set from a different vendor and will change them again..... not sure why I'm doing this though..........
Coolant --> New 50/50 premix. Filled and bled using Dougs method.
Behavior : The car warms up faster than before, suggesting I had a sticking thermostat previously (Good). Both fans work correctly..... ie first one is on at key on, and second one comes on and stays on at a lower point on the temp gauge than before (good). At idle the temp will go up to around the middle of the gauge, ie 12 o'clock (I have a "real" gauge on my '92, not the earlier barrel type gauge) it will creep up a bit past that, but even after 30 minutes of idling with the A/C on, it was only a little bit past 12 o'clock. However, when the car is driven, the temperature gauge goes up further, towards then end of the "ok" part of the gauge. After pulling over to the side of the road in this condition, the temperatures read by IR on the rubber of the top hoses is 200~202deg, and around 190deg on the rubber of the bottom hose. I also have an oil temperature gauge which is showing at that time the oil temp is approaching 200deg. Interestingly if I leave the car idling, the temperature will start to creep DOWN a little but I haven't left it long enough to see if it will get back to the 12 o"clock position. It would probably run out of gas first.
My thoughts : When the car was not overheating (before I started all the work reported above) the IR gauge would read 190deg on the top hoses. The temp gauge would just about reach 12 o'clock, then the aux fan would cut in, and the temp would go down a little. The gauge never got past the 12 o'clock mark. My oil temp never got much past 180deg. Based on this, and the fact that now I am getting >200deg IR when the temp gauge is much higher than it is before, and my oil temp is approaching 200deg, I think the gauge is reading correctly and the car is really running hot. If the IR temperature on the left hand top hose is correlating well with the temp gauge (and therefore the temp sensor, which is sitting behind the left hand thermostat), I think the thermostat is open. The fact that the left hand and right hand top hoses read within 1 or 2 degrees of each other suggests the issue is not associated with one particular bank. The fact that the car can almost maintain temp at idle, but struggles to do so at speed, suggests a flow issue. A flow issue could be because the thermostats are not fully opened, only open a little, or because the water pump is struggling, or because I've ran out of coolant pixies in the oodle tank.
HELP !!
(I'm going to change the thermostats again as I didn't like the rubber ring part) If that doesn't work I give up and the car goes to my indy mechanic
Details :
Radiator --> New Aluminum one from fasterjags. All crud cleared out from between the condenser rad and the engine rad when I pulled the old radiator.
Fans --> mechanical fan removed. Twin electric fans and shroud fitted. Both fans are sucking, ie pulling air in through the radiator. First one is ignition live. Second one is controlled by the temp switch in the water pump housing, same way as the original electric fan was wired.
Temp switch --> Changed to a lower temperature one, switches on at 82deg C
Thermostats --> replaced with new ones. 190deg C. They have jiggle pins. Jiggle pins are at the top / 12 o'clock position. They had strange rubber rings around the outside and I had problems getting them seated and fitted...... I've ordered another set from a different vendor and will change them again..... not sure why I'm doing this though..........
Coolant --> New 50/50 premix. Filled and bled using Dougs method.
Behavior : The car warms up faster than before, suggesting I had a sticking thermostat previously (Good). Both fans work correctly..... ie first one is on at key on, and second one comes on and stays on at a lower point on the temp gauge than before (good). At idle the temp will go up to around the middle of the gauge, ie 12 o'clock (I have a "real" gauge on my '92, not the earlier barrel type gauge) it will creep up a bit past that, but even after 30 minutes of idling with the A/C on, it was only a little bit past 12 o'clock. However, when the car is driven, the temperature gauge goes up further, towards then end of the "ok" part of the gauge. After pulling over to the side of the road in this condition, the temperatures read by IR on the rubber of the top hoses is 200~202deg, and around 190deg on the rubber of the bottom hose. I also have an oil temperature gauge which is showing at that time the oil temp is approaching 200deg. Interestingly if I leave the car idling, the temperature will start to creep DOWN a little but I haven't left it long enough to see if it will get back to the 12 o"clock position. It would probably run out of gas first.
My thoughts : When the car was not overheating (before I started all the work reported above) the IR gauge would read 190deg on the top hoses. The temp gauge would just about reach 12 o'clock, then the aux fan would cut in, and the temp would go down a little. The gauge never got past the 12 o'clock mark. My oil temp never got much past 180deg. Based on this, and the fact that now I am getting >200deg IR when the temp gauge is much higher than it is before, and my oil temp is approaching 200deg, I think the gauge is reading correctly and the car is really running hot. If the IR temperature on the left hand top hose is correlating well with the temp gauge (and therefore the temp sensor, which is sitting behind the left hand thermostat), I think the thermostat is open. The fact that the left hand and right hand top hoses read within 1 or 2 degrees of each other suggests the issue is not associated with one particular bank. The fact that the car can almost maintain temp at idle, but struggles to do so at speed, suggests a flow issue. A flow issue could be because the thermostats are not fully opened, only open a little, or because the water pump is struggling, or because I've ran out of coolant pixies in the oodle tank.
HELP !!
(I'm going to change the thermostats again as I didn't like the rubber ring part) If that doesn't work I give up and the car goes to my indy mechanic
Last edited by Sarc; 08-28-2012 at 06:44 PM.
#18
08-28-2012, 05:34 PM
Senior Member
Im thinking pixies...
after you change the thermos i bet she will run cold.
Maybe the water pumps fins in there are shot at higher rpms its just doesnt push enough flow.. just a thought
I drove mine from san jose to sacramento yesterday in 90* heat. and my gauge for most of the journey was reading in between the N and the H now i still think my new sender is bad or something, with the IR reader i was getting 188+right side and alittle over 192 on the left. never had a issue. anyone one what temp the v12 usually runs at?
after you change the thermos i bet she will run cold.
Maybe the water pumps fins in there are shot at higher rpms its just doesnt push enough flow.. just a thought
I drove mine from san jose to sacramento yesterday in 90* heat. and my gauge for most of the journey was reading in between the N and the H now i still think my new sender is bad or something, with the IR reader i was getting 188+right side and alittle over 192 on the left. never had a issue. anyone one what temp the v12 usually runs at?
#20
08-28-2012, 09:39 PM
Senior Member