Charging A Car correctly .

[Simeonx1]

Most cars i look at the dont tell you how much gas is in the system .

So when the system is low on gas . say 3/4 full . going of the pressures and the air not been as cold as it use to be .

if it was any less than 3/4 full i would pressure test it ect .

But how can i charge a system if i dont know the total amount of gas to put in .
All you can do is go of the pressures / air temp of and the temp of the pipes ?
Should i try doing the super heat ?

what are normal running pressure for a standard 134a system .

. I have my license and ive been working for 7 years . just not on cars .

[aircool]

all cars have a plate on with gas charge on it..otherwise try google,thats how i found out a bmw needed 500gram charge

[sonkax]

http://ariazone.com/service_manuals.php i think here you will find q-ty for every car

[charlie patt]

most makes have a trend plate telling you capacitys / in the uk we have a cd with 95 percent of capacitys of vechicles if part chargeing i go by standing pressures / air of evap/ pressures /as far as superheat thats a bit keen on a car but suction pipe sweating well is also a good check we dont have your ambients overhear but warm the vechicles up inside and top up charge 100grams ata time then wap on cold check pull down time pressures and suction pipe sweating well most of our cars have condensor fan sppeds and you can tell how full it is by what spped the condensor is on. ie a new type galaxy wont hit high speed outside this time of the year but in the workshop ot should switch between medium and high speed some of yhe jap vechicles have sight glasses to

[paulg88]

If its missing any of it's charge, there's obviously a leak which needs fixing regardless of how small...

[Simeonx1]

If its missing any of it's charge, there's obviously a leak which needs fixing regardless of how small...

actually theres a rule somewere saying you can add more gas into a car or truck . if it has a small leak and you have tried your best to look for it . thats what i learned at tafe . dunno if this is just an australian rule . but i defo remember learning about it .

it is a worry having 300000 cars on the road with tiny leaks though :S .

Thanks for your help . charlie .
there seems to be alot of cars that dont have a plate or have writting that has worn of.

[monkey spanners]

Most garages have a book or computer program that lists all the fill quantities of cars, so either have a word with the chaps that look after your truck or phone a main dealer of the make of car you are working on.

[chemi-cool]

All cars AC are leaking.
leaks are through the shaft seal or flex tubes.
One of the best way to minimize the leaks is to connect a relay to the reverse light that operate the compressor and hence lubricate the shaft seal.

Why in the middle of winter you worry about car AC?
I only switch it on when temps are above 35C.

[Simeonx1]

Some of the old fords came stock with the air con running when in reverse .

Yes i always tell people to run the air con once a week.

[charlie patt]

there must be a code on this autodata disc it will not load and send any vechicles you need i will gladly list it will varie from country to country

[cadwaladr]

i get fed up with people asking can i recharge car ac give them the same answer as i do with people who ask me about domestic fridges quote i only do them for family whoever they ! are car ac in the uk you been sniffing helium put the window down.

[fenair]

Mate,
if there is no charge weight plate on the car, try the net,
if you are doing cars on a regular basis, then i suggest you buy yourself a copy of auto-data, either cd rom or a book, look on ebay, as you should be aware that there are different types of oil and you should consider the correct quantity to add when servicing the system.

If you have qualified for your MACS certificate, all of this you should already know,

why should you suppose a system is 3/4 full, the correct method as with any refrigeration system, should poor performance be suspected,

is to reclaim and weigh out the contents, cross reference you amount with the recommended weight from the manufacturer, if there is less than quoted, then perform what you have been trained to do on your MACS course.
Reclaim, vac, pressure test with ofn, if pressure loss, leak trace all components, once the leak is sourced rectify and/or replace, repeat pressure test, vac, add oil, and charge.

On vehicles, it is not best practice, to simply use gauges as a determination of system performance, simply there is the variable of engine heat, coolant heat etc that will give different readings, compared to a fixed a/c system or fridge, remember the condenser sits mm away from the radiator, when first started the coolant in the rad is at ambient, but soon will rise to around 92 deg C +, this will effect your readings, if you were to use a comparator for example,

and to confuse the issue further, it also depends were the manufacturer has place the service ports in relation to the layout of the system, some models have both high and low, some have a high only and some have a high fitting on the low side,

so be careful, look, understand and don't assume, motor manufactures don't want us doing there service center's out of work , so they are coming up with ingenious ideas each year...

If you have a particular model you want to know the weight of , PM me and i will tell you..

Regards
pat..

[Simeonx1]

thanks i was just interested , rarely work on cars , and the list above does help if i do run into one.

I Work on trains which are kinda like a car but abit more advanced . its easier to work out how much the system needs but still abit annoying.