Clutch Fan vs Electrical Fan

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Green Giant
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Maddie;28051 wrote:Alternatively, get a Landrover Thermostat which opens at 76C, maintain the cooling system well, use coolant/distilled water 50/50 mix, install a low load pusher fan, and avoid using the AC during the drives. This will result in a lower running temperature and the Viscous Clutch Wont kick in so often.

Everyone, your inputs please ...
thanks Maddie, you have obviously looked into this in detail. Have you tried the Land Rover thermostat? My temp gauge shows about 105 when up to temp which I understand is normal, however when stationary for more than 5 mins it goes up to 125. The cooling system is properly filled 50/50 and has been flushed twice (by previous owner) in last 2 years. The radiator was replaced within the last 2 years as well according to the history I got with the car.

i dump the heat through the heater matrix when it happens but would (obviously) prefer a more engineered solution!

Any other comments from fellow TJ owners.
Maddie
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Spencerj702;28155 wrote:thanks Maddie, you have obviously looked into this in detail. Have you tried the Land Rover thermostat? My temp gauge shows about 105 when up to temp which I understand is normal, however when stationary for more than 5 mins it goes up to 125. The cooling system is properly filled 50/50 and has been flushed twice (by previous owner) in last 2 years. The radiator was replaced within the last 2 years as well according to the history I got with the car.

i dump the heat through the heater matrix when it happens but would (obviously) prefer a more engineered solution!

Any other comments from fellow TJ owners.
Thank Jeremy and Congrats on the Green Giant !!

The credit of my knowledge mostly goes to Chief marshal, Abu jimmy and Strawb as well as Jerry Bransford from jeepforum.com !!

I have tried the Landie Thermostat and the temp stays around 76 or thereabouts normally but if idling for more than 10 minutes during the afternoon it climbs towards 90 to 95.
The Tj with its own Thermo stays near the centermark and may climb after the mark but 125 means the system is somehow ovewrheating!! Have you tried replacing the radiiator cap? Does the coolant overflow when it hits 125?

Dumping the heat through the heater is a viable option in cooler climates, using done by rock crawlerrs but in our 'lovely desert temperatures' would be a little bit uncomfortable :P .

I have take off the heater lines altogether.
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Green Giant
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Hi Maddie,

No there isn't any overflow when the gauge goes into the red - I need to do more investigation and see if there is anything I have missed. I am having a full service on Wednesday so will get them to flush the cooling system.

thanks again.
Code Red
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Using a lower temp thermostat will help a little on startup, but doesn't actually increase the cooling capacity of the system. A thermostat is simply a valve that opens when it reaches a specified temperature. The lower rated thermostat will open a little sooner, but it's opened all the way by the time it reaches 76 degrees. Thus it won't really flow any more water when the engine is at operating temperature than the stock unit will. I have used lower temp thermostats to "cheat" and give me a few more minutes on a vehicle I was just driving around town, but it just delays overheating by a few minutes, it won't prevent it.

If your temp is going up when you are sitting still, then you may have an airflow problem. Do you have any obstructions in front of the grill? Winches, lights, etc... all interrupt the airflow which is marginal at best on a Jeep. You should also be looking at your clutch fan. It may be slipping too much and not flowing enough air.

If the problem is worse when your sitting still (the point when the engine is producing the least heat load), and gets better when moving (higher heat load, but more air and water because of forward motion and higher rpms) then your radiator is capable of cooling the Jeep as long as it is getting sufficient air/water flow. So you need more air (fan, obstructions, etc...) or more water (coolant level, water pump).

Just my $0.02.
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Spencerj702;28173 wrote:Hi Maddie,

No there isn't any overflow when the gauge goes into the red - I need to do more investigation and see if there is anything I have missed. I am having a full service on Wednesday so will get them to flush the cooling system.

thanks again.
At flushing the system, as it is done by cold water mixed with chemicals, the thermostat must be removed, otherwise they'll be flushing only radiator and not the whole system...
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caprihorse
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Code Red;28179 wrote:Using a lower temp thermostat will help a little on startup, but doesn't actually increase the cooling capacity of the system. A thermostat is simply a valve that opens when it reaches a specified temperature. The lower rated thermostat will open a little sooner, but it's opened all the way by the time it reaches 76 degrees. Thus it won't really flow any more water when the engine is at operating temperature than the stock unit will. I have used lower temp thermostats to "cheat" and give me a few more minutes on a vehicle I was just driving around town, but it just delays overheating by a few minutes, it won't prevent it.

If your temp is going up when you are sitting still, then you may have an airflow problem. Do you have any obstructions in front of the grill? Winches, lights, etc... all interrupt the airflow which is marginal at best on a Jeep. You should also be looking at your clutch fan. It may be slipping too much and not flowing enough air.

If the problem is worse when your sitting still (the point when the engine is producing the least heat load), and gets better when moving (higher heat load, but more air and water because of forward motion and higher rpms) then your radiator is capable of cooling the Jeep as long as it is getting sufficient air/water flow. So you need more air (fan, obstructions, etc...) or more water (coolant level, water pump).

Just my $0.02.
Some more details are written here - http://www.almost4x4.com/vb/showthread. ... Inspection
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Green Giant
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Code Red;28179 wrote:Using a lower temp thermostat will help a little on startup, but doesn't actually increase the cooling capacity of the system. A thermostat is simply a valve that opens when it reaches a specified temperature. The lower rated thermostat will open a little sooner, but it's opened all the way by the time it reaches 76 degrees. Thus it won't really flow any more water when the engine is at operating temperature than the stock unit will. I have used lower temp thermostats to "cheat" and give me a few more minutes on a vehicle I was just driving around town, but it just delays overheating by a few minutes, it won't prevent it.

If your temp is going up when you are sitting still, then you may have an airflow problem. Do you have any obstructions in front of the grill? Winches, lights, etc... all interrupt the airflow which is marginal at best on a Jeep. You should also be looking at your clutch fan. It may be slipping too much and not flowing enough air.

If the problem is worse when your sitting still (the point when the engine is producing the least heat load), and gets better when moving (higher heat load, but more air and water because of forward motion and higher rpms) then your radiator is capable of cooling the Jeep as long as it is getting sufficient air/water flow. So you need more air (fan, obstructions, etc...) or more water (coolant level, water pump).

Just my $0.02.
i agree - as I have only had the car a little over a week there are lots of things I will check. Airflow does appear to be the main problem so will have a good look around the rad area. Yes it is fitted with a winch and recently had the AC cores replaced. The work was done by Off-road Zone so I assume they did it correctly. They have also maintained the car for the last 18 months or so!

It it is there for a full service tomorrow so will speak to them too to see what they think.

thanks for the comments Code Red.
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Green Giant
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thanks Capri - was reading your thread at 4am! I used to do loads of my own repairs and works on my cars but in recent years the gadgetry and wizardry of electronics tend to preclude the do it yourself approach. The TJ however should allow me to tinker more - need to move to a villa with a garage as my apartment block car park is not the ideal environment!

see you on Friday if all goes well tomorrow!
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Spencerj702;28155 wrote: The cooling system is properly filled 50/50 and has been flushed twice (by previous owner) in last 2 years. The radiator was replaced within the last 2 years as well according to the history I got with the car.
Not A Jeeper but just a general thought, you might want to get these checked yourself, also check if the water pump was replaced and its not rusty that was the case with my XJ.

seller will say anything to sell.

I always ask one thing WHY do you want to sell anything and I always get some interesting un-realistic answers.

When I got my Jeep I was told by previous owner that he had replaced radiator, brakes, full service done, and many other things, I only came to know what happened to it after taking it to the Almost Garage and had to actually replace all these, now I know what has actually been done to my jeep and if its reliable or no.
DesertDawg
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Hi,

This is my experience with XJ cooling - clutch fan vs electric.

My XJ 4.7 stroker came with twin stock electric fans. This was not sufficient. I reverted to stock (fan clutch + aux electric fan) and Dolphin radiator + bonnet vents + spaced hood. This just about keeps it cool in the desert if I am not too agressive. Fine on road and in traffic.

I have also tried a two speed volvo electric fan (taurus fan motor). This was ok'ish, but not as good as stock. Engine response far better.

I am now about to embarck on my next modification - twin Sabaru fans mounted in front of radiator (as seems standard in almost 4x4 - thanks Strawb).

The XJ radiator is very small and the stock cooling is always 'on the edge'.

Dave
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