Most would know that I re-did my cooling setup about 9 months ago. I did it after some overheating trouble while pulling my offroad camper trailer in low range on long climbs in the bush. I already had twin electric fans with one stock 8 blade AC one and a 2500 cfm 16" electric. That had worked well for many years but slowly started to get problems in the last couple of years but only on long steep climbs and no other time.
So I decided it could be my custom 3 core radiator getting old, even though I had had it cleaned, the auto causing the radiator to run hotter or vice a versa as auto would be slow to shift, or needed more fan speed.
Thinking about it I decided I would rather attack all fronts at once rather than wait until the end of the year in the Australia summer to find out if it had worked or not.
First thing I did was decide to go to a 2 row radiator instead of the 3 row. Might sound strange but the new 2 row had as many tubes as my old 3 row. But they were bigger and also allowed more air to pass through the 2 rows rather than 3 which can be a problem when only relying on fan suction.
http://www.go.jeep-xj.info/HowtoRadiatorFitting.htm
As you can see it has 39 tubes per row.
I then added a Ford Taurus fan which has 2 speeds. But instead of just using this horizontally like others had done, I added it vertically leaving the extra hanging out the bottom and still having my stock AC fan in place. There was a double reason for doing it this way as you soon see.
http://www.go.jeep-xj.info/HowtoTaurusFanInstall1.htm
At the same time I also fitted a large auto cooler. But rather than blocking airflow through the radiator and also heating up that air before it got to the radiator, I added it below the radiator filling the extra length in the Taurus fan shroud.
http://www.go.jeep-xj.info/HowtoAutoCooler.htm
Trouble I came across with it like this was that the thermostat could not keep the temperature stable. It would stay closed until the temperature reached 195*F, like it is supposed to, but as soon as it started to open the coolant rushed through and the cold coolant running back into the engine would make it plummet to 160*F before it would then start to climb again. Would do this up to twice every minute. Drove me nuts and was costing me fuel with it going in and out of closed loop mode. Part of the problem I think was the highflow water pump and the large radiator tubes. I was running a Robertshaw thermostat so tried a new one as well as a Jeep dealer one along with 2 other brands. Made little difference. In the end I fitted a restrictor that I made which had the side benefit of keeping the pressure higher inside the block once the thermostat opened. This helps steam from forming in hot spots. Does not increase the pressure above stock while the thermostat is closed so there is no worries about the pressure causing any problems to hoses etc. This along with a Superstat Thermostat, #45359 gave me the most stable temperature I have ever had in any car or Jeep.
http://www.go.jeep-xj.info/HowtoRadiatorRestrictor.htm
Now I waited this long to give final results as there was a particular climb on the border of NSW and Victoria that just climbs relentlessly and that I didn't make it to the top of due to overheating while towing last year. It is a climb in low range that takes around 20 minutes to reach the top. Not very hard but just the time it takes takes a toll on the cooling system and the slow speed does not allow any air assistance from moving. Well I went back there almost on the same day a year later just recently and it was only 2* cooler than the year before. I was a bit nervous to see what would happen this time and even thought I would try with the AC on and heater off as last year had to turn it off and run the heater to try and help it keep cool. To really test it out I even left the fan override off and on the low speed. Well I am proud to say it climbed it no worries at all and the hottest it got to was to turn the fans on automatically. After that when I would see a long low range climb come up I would flick the fan into high speed, as was getting close to the 100*F outside by this stage, and never once did it go more than a couple of degrees over when the fans would come on.
I have just got so much confidence back and feel I have just the perfect system for all occasions now.
So I decided it could be my custom 3 core radiator getting old, even though I had had it cleaned, the auto causing the radiator to run hotter or vice a versa as auto would be slow to shift, or needed more fan speed.
Thinking about it I decided I would rather attack all fronts at once rather than wait until the end of the year in the Australia summer to find out if it had worked or not.
First thing I did was decide to go to a 2 row radiator instead of the 3 row. Might sound strange but the new 2 row had as many tubes as my old 3 row. But they were bigger and also allowed more air to pass through the 2 rows rather than 3 which can be a problem when only relying on fan suction.
http://www.go.jeep-xj.info/HowtoRadiatorFitting.htm
As you can see it has 39 tubes per row.
I then added a Ford Taurus fan which has 2 speeds. But instead of just using this horizontally like others had done, I added it vertically leaving the extra hanging out the bottom and still having my stock AC fan in place. There was a double reason for doing it this way as you soon see.
http://www.go.jeep-xj.info/HowtoTaurusFanInstall1.htm
At the same time I also fitted a large auto cooler. But rather than blocking airflow through the radiator and also heating up that air before it got to the radiator, I added it below the radiator filling the extra length in the Taurus fan shroud.
http://www.go.jeep-xj.info/HowtoAutoCooler.htm
Trouble I came across with it like this was that the thermostat could not keep the temperature stable. It would stay closed until the temperature reached 195*F, like it is supposed to, but as soon as it started to open the coolant rushed through and the cold coolant running back into the engine would make it plummet to 160*F before it would then start to climb again. Would do this up to twice every minute. Drove me nuts and was costing me fuel with it going in and out of closed loop mode. Part of the problem I think was the highflow water pump and the large radiator tubes. I was running a Robertshaw thermostat so tried a new one as well as a Jeep dealer one along with 2 other brands. Made little difference. In the end I fitted a restrictor that I made which had the side benefit of keeping the pressure higher inside the block once the thermostat opened. This helps steam from forming in hot spots. Does not increase the pressure above stock while the thermostat is closed so there is no worries about the pressure causing any problems to hoses etc. This along with a Superstat Thermostat, #45359 gave me the most stable temperature I have ever had in any car or Jeep.
http://www.go.jeep-xj.info/HowtoRadiatorRestrictor.htm
Now I waited this long to give final results as there was a particular climb on the border of NSW and Victoria that just climbs relentlessly and that I didn't make it to the top of due to overheating while towing last year. It is a climb in low range that takes around 20 minutes to reach the top. Not very hard but just the time it takes takes a toll on the cooling system and the slow speed does not allow any air assistance from moving. Well I went back there almost on the same day a year later just recently and it was only 2* cooler than the year before. I was a bit nervous to see what would happen this time and even thought I would try with the AC on and heater off as last year had to turn it off and run the heater to try and help it keep cool. To really test it out I even left the fan override off and on the low speed. Well I am proud to say it climbed it no worries at all and the hottest it got to was to turn the fans on automatically.
After that when I would see a long low range climb come up I would flick the fan into high speed, as was getting close to the 100*F outside by this stage, and never once did it go more than a couple of degrees over when the fans would come on.I have just got so much confidence back and feel I have just the perfect system for all occasions now.
