Engine and air con cooling fans.

[frank rabbets]

I thought I might improve my air con by fitting an electric fan in front of the condenser. It does not seem very cold when the car is stationery with reduced air flow. The fan would start when the pump did. Any thoughts.

Why is there an increased idle when the air con comes on?

1. To overcome compressor resistance.

OR

2. To increase condenser air flow.

Has anyone fitted an electric cooling fan instead of the belted one?

Cheers

 

[Towpack]

I wouldn't have thought an extra fan in front of the condenser would make much difference personally. There will always be some air flow when stationary as the VC fan will still be turning. The idle up actuation when the AC cuts in is to counteract the load of the compressor IMO, although it will also have the effect of increasing both the airflow through the condenser (slightly) and the flow of refrigerant round the system. I've been using mine all the time lately and I can't say I've noticed it being any less cold when stood in traffic etc, although I seem to remember similar symptoms developed when the AC pressure was slowly dropping due to a very small leak in the system a couple of years back. I've heard of people fitting electric fans and even seen one but that was to 'improve' engine cooling and warmup. JMO

 

[Dave]

If you measure the high pressure at idle, it will tell you if you have an airflow problem. Probably not though, as the demand reduces with the reduced compressor speed.

 

[frank rabbets]

Right then it's 2 1/2 years since it was regassed so I'll get it done before experimenting.

I'll fit 2 fans, one for the engine cooling and another for the air con. I'll also fit a temperature warning buzzer.

I've looked on ebay just for info and I notice some cars are fitted with a neat dual fan kit just for this purpose.

My Ultima had a very powerful air con cooling fan as the evaporator was at the back. Icy cold air instantly.

Thanks for the help.

 

[chapel gate]

some 80s in warmer climes were fitted with a electric fan from factory.

 

[pberrey]

I can't imagine a 4.2td struggling to drive a healthy aircon system even at tick over. I would get it regassed first as Frank said. I would also check your viscous fan is pulling air and not just windmilling. I've just rebuilt mine because it wasn't actually drawing air through the rad.

Electric fans are ok but you will need to install a temperature sensor into one of the coolant hoses and wire it up with a relay. Having said that I will be fitting one - or two smaller fans - once I have refitted a/c into my 80. I have an X-engineering kit which was spare from the Defender challenge truck I had before the 80. I will keep the viscous fan for engine cooling.

 

[Towpack]

The VC fan will always pull some air through the rad, even when stationary and before it fully engages when the engine temp gets high enough. Electric fans will always assist quicker warmup because of this but they don't cool a hot engine any better than a correctly functioning VC fan IMO.

 

[Dave2000]

I have always been an advocate of electric fans and feel it is always a good upgrade and invariably the debate will heat up (no pun intended) as the thread progresses. I used two on my 500 BHP MANUAL V12 JAG Coupe a few years back with no problems, and on my previous 4x4 (LR Discovery) again no problems even when off road racing with it. I have plans to fit at least one electric fan to the 80 as it WILL increase AC cooling Frank at idle. I have done a couple of checks and even holding a cheap Kenlowe in front of the rad brought down air temps from the vents, I used a laser detector and confirm at least a 6 degree drop, viscous was new only a year before. My plan is as follows, I will use a two stage controller so the fan can run slowly when in traffic just to control engine temps whether the AC is on or not, my driving environment apart from August (tourists) means if I am behind more than two cars at the traffic lights I am in a serious traffic jam

If the AC is on then the fan/s will run at full speed, as the vehicle speed increases the fans (AC or not) will no longer be needed, and here Frank YOU gave me the answer. Frank, you recall putting the reverse light switch in the wrong hole during a recent gearbox rebuild activating your reversing lights in 5th? I am going to use that hole and an extra switch with a relay to short the power supply to the fans or controller, that way the fans will always be off when in 5th, simples!

As mentioned my environment rarely sees traffic although we do experience high temps, so a temp switch with dual contacts or a controller with a similar two stage switching capability is the way to go. You can purchase a tube that goes in line of a main rad pipe, this has a threaded union to accept the aforementioned switches. As an asides I am using one to change my coolant recovery tank system to a constant flow/exposed to coolant pressure type with a level sensor, something Toyota forgot to do with the current system!!

I have an old rad I kept in the garage which I will use as a template to make the fan mounts, IIRC there is a car in the US that has a 'serious' electric fan...might be a Lincoln? They are used by the rodders out there on 400+ V8's so we might get by with our 'sixes'. I would not bother with the Pacet/Kenlowe gear as experience dictates they are OK as 'add ons' or 'secondary' but soon run out of puff when used on their own, look for something used in mass production etc.

regards

Dave

 

[frank rabbets]

Dave that's all very interesting. These modern fans can be really powerful. The 2 on my ultima cooling rad blew the 30 amp fuse and I had to fit 2x 30 amp fused relays.

On the 80 there is a large gap between the a/c rad and cooling rad. Also the a/c rad surrounds are not sealed so sir can be drawn round the side of it especially at idle when there is sucked through the a/c rad rather than pushed through it with the car in motion. I think that's why your experiment with an electric fan up against the a/c rad was so successful.

You'll be after a reverse switch then!

I've had right fun and games here. I refilled the cooling rad and water was pouring out of the core. F,F,F,F, . I drained it down and assumed I had pocked a hole with a temp sensor I was using so was looking in that area bot could not find a hole so ordered a new rad. Then on refilling and checking found a cut tube right in the middle just as if a Stanley knife blade tip had nicked it. Only 1/4 mm diameter so cured with a blob of hard solder. Don't remember damaging it there at all. It's made my belief in infinity stronger i.e. if you wait long enough everything will happen, never damaged a rad before . Apart from crashes. In another 10,000 years I'll be welding con rods to my crown wheel.

 

[frank rabbets]

The engine cooling rad must have a lot of excess capacity when clean. I washed through the fins with a hose and tuns of dirt came out. This did not compromise engine cooling but must have obstructed air flow for the a/c rad ?

When I soldered the nick I'd made I noticed the cooling tubes are brass. On others vehicles I've worked on the tubes were copper which does not last as long? Perhaps this explains the £375 for the genuine Toyota ones?

 

[Dave2000]

You are right about the cooling capacity, I have run around with no cowling on for ages just to see if it made any odds and the answer is an emphatic no. As I have the temp gauge mod (it is on my MUD thread), the gauge is very accurate and responds very quickly to temp changes.

When I purchased my 80 I noticed the rad core was toast, I bought an aluminium/plastic one, copes fine with Spanish weather mate, again this bring us to the capacity of the cooling system, remember when the are loaded and have a trailer IIRC the train weight is around 7 ton?

regards

Dave

 

[Dave2000]

Went back to my research made last year, the fans the guys 'over the pond' tend to go for is the Lincoln VIII, loads and loads of 'gumpf' out there about it along with plenty of mentions about blown relays, as it is apparently a serious bit of kit., I have ordered a cheap second hand one from ebay to try it out, just waiting on a possible gear/transfer box fingers crossed and if the car is on the road in the next few weeks it will get a serious test in the temps we have at the moment, 39c yesterday frying eggs on the terrace.....seriously!

regards

Dave

 

[Chris]

Mine doesn't seem to idle up when static hence it leading to near stalling last week when in France. Lovely and cold, but certainly hit the idle speed when parked for sure.

 

[frank rabbets]

That reminds me. I checked my steering idle up by getting Anne to waggle the steering and the diaphragm pushrod moved. The engine idle RPM was beyond its limit at that point but obviously its going to work because it almost touches the lever and if the revs were much lower it would have increased RPM.

 

[frank rabbets]

HOW TO DO AWAY WITH THE NEED FOR AN A/C FAN

Get an air con man in who does not know what he's doing worked for me.

So he arrives and connects his hoses to the a/c pump and starts venting the gas to the atmosphere. Gosh I've got a criminal doing my air con. Then when all is gone he connects his vacuum pump with no reservoir, just a vent, and I can see vapour pouring out. "Does it evacuate the oil as well" I ask. " Do you know I've never thought of that......................I always put an once in anyway." So the gas and oil are connected up " I've had a look on line before with your REG but couldn't find your car. The land cruisers vary from 800gm to 1000gm so yours should be about 900gm". So I start the engine and turn the air con on. It's getting f-cking icy as he says " About up to 300 gm at the moment". I'm now convinced my air con has a very limited life so I decide to let him put the whole nine yards in and wait for the bang. "Up to the 900 now". I've long since turned the air con off as I'm freezing.

 

[sae70]

Different vehicle I know, but Swampy idles up slightly when the air-con pump kicks in. I noticed her do it only a couple of days ago while stood talking to a chap in a Hi-Cap LR90. Since fitting the digital engine temperature monitor I've noticed an increase of between 4 & 6°C in engine running temps depending upon speeds and outside temps when running with the air-con on.

 

[frank rabbets]

Does it depend on exactly where your temperature probe is? It needs to be inside the engine water jacket. I spent 12 months doing experiments on the relative expansion of metals with a jig bolted to the garage floor. I had a hot water jacket 1 metre long with rods of different metals connected to dial gauges. My probe was on the outside of the brass water jacket but was insulated, so I thought. But the temperature inside the jacket was much hotter as I later discovered. I would think the water temperature inside the top hose is at least 5 degrees cooler than that inside the block. there's a very quick drop off. I tested my thermometer in a kettle of boiling water and it took 30 secs of boiling before it reached 100 degrees. After 15 secs the temperature dropped to 95 degrees.

 

[sae70]

My temperature probe has always remained in the same location since installation. Under one of the bolts that holds the top hose connection to the top of the cylinder head. I'm less interested in what the actual water temperature is or the oil temperature come to that, but more if there is a change from what I consider to be the norm. Since cleaning the Radiators and servicing the cooling system she's been running between 76 & 83 indicated on the gauge dependant on outside temps and what I'm using like the Air-Con. As said I've no idea what the actual water temp is, but I'm very impressed with how responsive the indicated temperature is to any change and am certain it would give the early warning I would desire of impending doom

 

[sae70]

Here's a couple of piccys of the probe location

 

[Towpack]

Still can't see the need for an AC fan if the system is working well IMO. Mine will still get down to an indicated 4.3 deg C in traffic on a hot day, you can hear and see the engine revs rise when the pump kicks in. If the AC isn't getting cool enough then a fan may help it but it's addressing the symptom of the problem rather than the cause of it. JMO