Improved Engine Cooling?

[frans]

I just glanced over this thread, and I have a question. Sorry if it has been addressed already:

In terms of using a viscus fan clutch, or not, the main advantages to me seem to be; Better gas milage, and quieter operation.
But, is it true that you get better cooling without a fan clutch?
thanks
-frans

 

[muskyman]

I just glanced over this thread, and I have a question. Sorry if it has been addressed already:

In terms of using a viscus fan clutch, or not, the main advantages to me seem to be; Better gas milage, and quieter operation.
But, is it true that you get better cooling without a fan clutch?
thanks
-frans

I installed a ken lowe fan a number of years back in a RRC for a friend. He bought it after reading a UK based forum and he actually got about 2-3 mpg gain from it.

the noise level of the fan was pretty similar IMO to that of a standard clutch fan. he used the truck in the midwest USA so the climate is cool most the season but in mid summer can be very hot. The fan had a hard time keeping the engine cool during 95* weather with the AC turned on. Now that weather is rare here as we only have maybe 10 days a year that reach that temp. But during those 10 days having AC is something that is nice from a comfort standpoint.

In very similar conditions I have pulled my buddies jeep weighing just over 4000lbs with my disco with both the front and rear AC going full blast and didnt have any issues with cooling(allthough it could have used more power) One such trip was about 250 miles each direction so it wsent just a cross town trip the truck was lugging the jeep up and down some pretty big hills in those miles.

Like I said earlier, the cooling systems as built by land rover are very robust and can handle the hottest weather on the planet but that is very much dependent on the system working correctly and all the components to be in good shape to perform their function in the complete system.

 

[Snagger]

Like I said earlier, the cooling systems as built by land rover are very robust and can handle the hottest weather on the planet but that is very much dependent on the system working correctly and all the components to be in good shape to perform their function in the complete system.

That's the important thing to take from this. In good working order (maintained, but not brand new), the cooling on Land Rovers is perfectly capable of cooling the vehicle rgardless of what you're doing with it or where.

Some people like to fit electric fans to replace the viscous fan, but I think that's a big mistake. The engine driven fan has much higher capacity and power, and is more reliable than an electric fan. Engine remanufacturers like Turner Engineering and ACR warranty their engines for 12 months, but the warranty is voided immediately if the engine is run without its standard fan.

If you have a good look around modern quality cars, you'll find that electric fans tend mostly to be used where the engine is mounted transverse. Most in-line engines will have engine driven fans. Electric fans tend to be used where fitting mechanically propelled fans is impossible.

As for the effieciency of electric fans, I'm disinclined to believe the claims of the manufacturers. When you're driving along, the fan is not needed. An electric fan will stop, while an engine driven fan will continue to be spun. However, since the fan blades will have little angle of attack on the ram air through the rad, it will have very little drag. This is even more the case with viscous fans, whos' little remaining drag when "slipping" will be almost entirely offste by the ram airflow, so the drag would be vitually nil. When slow or stationary, the fan will cut in, and an engine driven fan is not only more effective than an electric fan, but also consumes less power as it puts no strain on the electrical system - an electric fan has to use engine energy turned into electrical power by the alternator ans back into kinetic energy by the fan motor, which is a very inefficient power transfer.

I had no choice but to fit an electric fan to my 109, but my Tdi RRC will never lose its viscous unit. A supplementary electric fan to assist the viscous unit may benefit some people, mainly just their paranoia, but it shouldn't be necessary, and certainly shouldn't be used to replace a stock system, in my opinion.

 

[ntsqd]

In my experience it is important to distinguish between an aftermarket electric fan and an OE electric fan. Those fans found on U.S. Ford Taurus' are in high demand in the off road desert racing world. They have been found to move enough air to keep a healthy (500+ HP) V8 cool, usually even while sitting still in the pits.

I've yet to see an aftermarket fan demonstrate that it could do this. They may be out there, but given the warantee issues an OE faces I don't expect any aftermarket fan to offer similar performance because they couldn't sell it at a reasonable price.

A very key feature of an electric fan is it's ability to run with the engine off. Barring those odd and unique to one engine hybrid electrical/mechanical water pumps an engine driven fan can't continue to draw air with the engine off. I have seen many OE installed supplemental fans intended to prevent hot soak problems with various systems. FJ60's have such a fan that blows solely on the carburetor.

 

[James86004]

My Chevrolet Silverado with the 5.3l longitudinally mounted engine has no engine-driven fan. It does have a big electric fan. No signs of cooling issues at all either, even in our hot temps and bad traffic in Tucson with the AC on.

Another point is the AC condenser on the NAS D90s is not very efficient. A more modern parallel flow condenser would make the AC work more efficiently, which would put less load on the engine.

Also, make sure it is actually overheating - check the temperature gauge.

 

[Snagger]

A very key feature of an electric fan is it's ability to run with the engine off. Barring those odd and unique to one engine hybrid electrical/mechanical water pumps an engine driven fan can't continue to draw air with the engine off. I have seen many OE installed supplemental fans intended to prevent hot soak problems with various systems. FJ60's have such a fan that blows solely on the carburetor.

A genuine question aimed towards the mechanics and engineers amongst you, but is that really desirable? If the engine is not running, then it won't be producing any more heat. If the engine is very hot, then allowing it to cool slowly with the bonnet up but no running fan would surely be better for preventing thermal stresses, warping or cracking of heads, manifolds and the like? Like I said, it's just a question, based only on my suspicions.

 

[Geo14cux]

One could turn on there a/c with the engine off. & have the best of both..
If you have a defender you could mount a pusher.
I like K.I.S.S.

 

[ntsqd]

A genuine question aimed towards the mechanics and engineers amongst you, but is that really desirable? If the engine is not running, then it won't be producing any more heat. If the engine is very hot, then allowing it to cool slowly with the bonnet up but no running fan would surely be better for preventing thermal stresses, warping or cracking of heads, manifolds and the like? Like I said, it's just a question, based only on my suspicions.

Turning off the engine suspends the pump, but there is still a thermal load in transit. At least one mfg of a vehicle I own thinks this is a good idea of running the fan above a set coolant temperature. My VW Rabbit diesel cycles the fan independently of the ignition switch position.

When you consider the thermal spike that happens on a normal hot shut-off this looks to me like a good idea. The loss of the water pump means that the system reverts to being what I've always heard called a "Thermocline System", meaning that the temperature difference in the various areas of the system 'pumps' the coolant through the system. As one might imagine, this is not a fast process so worrying about rapid cooling is not a high possibility.
Running the fan does speed things up somewhat, but nowhere near like running the water pump can. Were I operating a car cooled solely with an electric fan I would make this arrangement if it did not already exist.

 

[Steve Rupp]

My buggy (rover 4.0 engine) is going to have an electric water pump and electric fans on the rear mounted radiator. It will be setup so that when I shut down the engine I will still be able to continue cooling. This will be an interesting test and if it proves well I might consider the electric water pump on my discovery. The electric water pump isn't cheap though for the buick 215, $380 plus I will have to figure out what to do with the middle pulley.

 

[R_Lefebvre]

Steve, honest question: What are you hoping to gain with the electric water pump? The OEM's looked at this as a means of gaining fuel economy. I'm sure that's not your goal. The electric water pumps proved to be too costly, and too unreliable. So it was abandoned.

If it's for after run cooling, I've never seen it on any amateur race cars. You let the car idle in the pits until it reaches normal temp, then shut it down. I never even had to do that, it cooled down to normal temp during the cool down lap.

 

[ntsqd]

I've been told by my higher-ups that the Davies-Craig electric water pumps are used in some OE applications. Other than the smaller unit being used on the GT-40 in some non primary cooling pump capacity I do not know where or which.

 

[Steve Rupp]

It really has more to do with flow than cooling capability. I'll be using the chassis 1.75 .120 main tube to run the coolant to the back. I just have a feeling the stock pump isn't going be able to handle this.

 

[R_Lefebvre]

I've been told by my higher-ups that the Davies-Craig electric water pumps are used in some OE applications. Other than the smaller unit being used on the GT-40 in some non primary cooling pump capacity I do not know where or which.

Would that be the air/water intercooler water pump? I don't think it had an engine coolant electric pump. I have an F-150 Lighting intercooler pump on my Focus for the intercooler.

It really has more to do with flow than cooling capability. I'll be using the chassis 1.75 .120 main tube to run the coolant to the back. I just have a feeling the stock pump isn't going be able to handle this.

What's everybody else doing for this? Having a V8 engine at the opposite end of a car from the radiator isn't new. Guys building... say a Gt-40 kit car, are they using electric pumps?

Just seems like... the Rover community tries to exorcise all electrickery from their vehicles, and you're converting a mission critical component to electric. If anything goes wrong with that electric pump, you probably won't know until it's too late, unless you have a temp sensor on the block or something.

 

[dzzz]

A genuine question aimed towards the mechanics and engineers amongst you, but is that really desirable? If the engine is not running, then it won't be producing any more heat. If the engine is very hot, then allowing it to cool slowly with the bonnet up but no running fan would surely be better for preventing thermal stresses, warping or cracking of heads, manifolds and the like? Like I said, it's just a question, based only on my suspicions.

The engine running and the aux. radiator (the heater) on high.

There is heat in from the motor running, but the heat being extracted by the cooling system is much greater. Also, a very hot engine is not evenly hot. Turing everything off leaves some nasty hot spots.

 

[ntsqd]

Would that be the air/water intercooler water pump? I don't think it had an engine coolant electric pump. I have an F-150 Lighting intercooler pump on my Focus for the intercooler.

It very likely is that pump. I did not recall where it was used until you mentioned it. Pegasus carries both in the U.S. for anyone interested in one or the other.

On the desert race truck that I chase we have two radiators in it. The rules require a radiator up front, so it has one. The radiator that does most of the work is in the bed. GM 2.8l water pump does the job all by itself.

I realize why you might want to run the coolant through a chassis tube, but that usually that results in a less than ideal chassis design, it presents an opportunity for by-standers to be burnt, and it compromises the life of the chassis.
If you insist on doing this I would highly suggest coating the inside of the tube(s) with something like Moroso's ceramic engine sealant and use the old school foam insulation anywhere someone might come in contact with the tube(s).
We used "muffler-moly" for the plumbing to the rear radiator. Supported it on more "muffler-moly" saddles with hose clamps holding the tubes to the saddles.