Finally good fuel usage PJ PK Ranger -my story

The earlier Rangers are Mazda based with a Mazda engine.
This reversed in 2011? when they became Ford based with a Ford Transit engine..

Frank, the problem was not the seal but the application of sealant when some motors were built. Some had no problems and others did.

As said the motor is Mazda.

Hi
Background
All good auto aircon and all industrial aircon using R12 R134a refrigerant runs between 150-200psi pressure depending upon ambient .
The condenser does the cooling of refrigerant .
Excessive condenser pressures/temperatures influence the temp of the liquid refrigerant being fed to evaporator greatly . Hightemp pressure liquid gives poor evaporator performance and therefore poor cabin temp.

This is where it gets automotive influenced .The condenser running high temps = high pressures then loads the compressor . This generates compressor mechanical noise which is in addition to poor refrigeration performance .

Viscous coupling fans particular to Ford small utes Courier etc have never cooled condenserswell .
Why air cons still work albeit poorly a car company uses the smallest condenser possible they get away with .

Weight charging is done in automotive because
1/the sight glass is eliminated ,saves money .Sight glass is only good if ,,100% full charging = no bubbles .
2/ charging by weight is typically done when undercharging to avoid excessively high pressures because the condenser is to small . Under charging can starve the evaporator of 100% liquid feed .

Typically fitting of an electric fan on condenser does help but a larger condenser is the best solution for better cooling .

Swampy, all you say is correct......BUT.
They are text book facts that you are quoting, yes most apply in average ambient temps say around 40 degrees.

If an AC compressor cant handle 300 plus psi then it isnt very good quality as 300 hi side can be expected in the mid to high 40ies and is more likley poor quality or old oil that will lead to destruction. High pressure safety switches in caterpillar gear drop out at 380 psi.

The important thing for the evaporator to achieve low temps is refrigerant changing states from liquid to vapour, at higher temps it takes more pressure to to raise the boiling point of the refrigerant so it changes back to liquid in the condensor at higher temps, the liquid being hotter when it gets to the expansion device isnt as important as it actually being liquid.

If you were experiencing high pressures this time of year you may have had an over charged system or the condenser may have been partially choked up.

Yes lowering the operating pressure will use less energy but doing it by reducing the refrigerant quantity will work until the weather gets hot again, also you lose a little oil with the gas which is bad.

What method did you use to lower the pressure. By the way, what is your low side pressure?

Hi
Since the dawn of time R12 R134a has had ideal temps pressures to operate at. Few auto makers achieve this . Most in the commercial world do .

Condensor pressures are a by product of the charging process . To high fit another condenser

Evaporator
liquid supply must be 100%
measured by subcool = where liquid exists in the bottom row of condenser

-------Auto charging is typically restricted by excessive pressures this supplies less than 100% liquid
and causes less than ideal evaporator cooling . Less than 100% liquid supplies vapour. vapour cannot be used to cool.
Situation compounds ,say u get 100% charge loaded in but then the pressures are high . This either compromises performance or u fit another condenser to regain performance .

Evaporator-------supplied over temp liquid causes excessive flash boil //flash gas
Result ---flash boil reduces evaporator cooling capacity
How it occurs --high temp liquid passes thru TX valve , refrigerant is high temp the cooling capacity of the evap is then used to cool the liquid . The low pressure temp liquid can then be used as per normal functioning evaporator

Ideal condenser pressures restrict flash gas condition. This promotes MAXIMUM evaporator efficiency . This only occurs when the evap is supplied 100% full liquid line at correct pressure/ temp

Fitted second // improved condensers to container cranes /govt trucks /underground mine trucks and a few cars . All of these are in Northern Australia desert and tropical conditions .

Charged low pressures are governed by thermostat but also by the refrigerant freezing pressure .

Dont really see the point your trying to make by stating the obvious.
How did you lower your head pressure?

Hi
When u stated u charge by weight this said to me you are not aware of ALL the charging criteria that goes to maintaining an a/c system . Also compressors are not under a constant load if u connect a set of a/c gauges shows this . This is high lighted with an undersized condenser .
Further down I made mention of fitting larger and or second condenser to rectify pressure problem .
Ford seldom make there own compressors . Asian sourced cheaper copies of Nippon Denso is common Many other brands of vehicle do this as well ,Ford are not alone

No text book facts, purely well performing a/c units . To do any less workmanship in the ac industry gets u sacked .

I think you are getting me confused with RMD. I agree with you in saying his statements demonstrate his lack of experience in the field.
I basically just pointed out out that a compressor should be able to cope with 300 psi and asked how you lowered your head pressures?

Hi
A poor system has a huge pressure swing from idle to eg 2000rpm upwards of 100psi difference .
Other have a smaller swing but maintain a consistently higher pressure ,
Both situations require a bigger condenser ability .

When situations are ideal the pressure swings very little eg 40-50psi on a bad day.
Perfect conditions have as little pressure swing as possible .No different if idling or reving engine. All great systems are like this .

You cannot cool any refrigerant /R134a cooler than ambient eg gauge pressure 150psi= 43 cel is gas temp but also airflow over condenser core .

My Ranger 150-160 psi idling or reving on a very hot 45+ and very humid day 80%.
The a/c is now pleasure to use .

You seem to keep ratteling on about great systems and ideal systems, we all know perfect is only ever a fluke in anything automotive.
You continue to avoid the question.
HOW DID YOU LOWER THE HEAD PRESSURE ON YOUR SYSTEM?

hi
By fitting a second condenser. I have answered this several times now .

Oh, sorry about that, It appeared that you were just stating that it is often necessary didnt realise you were saying you actually had it done.

.
Can't be bothered Dave.

Maybe its a similiar problem to the early 300tdi landrover engine, Swampy , The oil seal housing used to warp due to poorly placed holding bolts causing a never ending weep.


Cheers Axle.