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Car re-gas help wanted please (o:

mr2madlad on Mon June 29, 2009 5:57 PM User is offline

Year: 1994
Make: Toyota
Model: Mr2 GT-S Turbo
Engine Size: 1998
Refrigerant Type: R134a
Country of Origin: United Kingdom

Hi

Am wanting help in a DIY re-gas for my car.

I have a 1994 MR2 Turbo that runs on R134a refrigerant, my condenser burst and I lost my charge - nothing I could do about it, I did manage to seal the hole with superglue as I know that moisture in the air does not do an A/C system any good, sealed it within half an hour of hissing finishing.

I bought a 13.5 Kg tank of R134a and a set of Refco manifold and hose set, I already have a 2.0 CFM vacuum pump I use for other projects so I will be using that to vacuum out the system, if that’s a good enough pump?

Replaced the condenser within 30 second of removing old one and now I am at the point of what ever I need to do.

Here is where my questions are:

1 how do you interpret / read the manifold gauges? Very basic question but apart from the pressure markings I have not got a clue.

2 what are good values for my car? - Have no idea what values should be.

3 how much R134a do I use? (Did find a PDF on this forum that said I need 25.5 Oz so I guess that’s sorted.

4 will the leak dye and oil still left in the system be ok as none came out with leak or do in need to inject new once vacuumed out?

5 will vacuuming it suck the oil and dye out? - can I catch it and stuff it back in or replace it?

6 Ambient temperature? Air temp before starting, general average air temp?

I am pretty confident in doing this myself, so is it just a case of vacuuming it out, holding vacuum to see if it leaks and if not sticking 25.5 Oz back in the low side (high side closed off) and it will work?

Have a set of kitchen scales that are fast reacting and accurate so guess I weigh the R134a bottle and then - 25.5 Oz and set scales to beep at me with bottle still on them when it gets to the correct weight, and yes they cope with up to 20kg.

Thanks for any help in advance.


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The man who makes things, or breaks things, you decide.

Edited: Mon June 29, 2009 at 5:59 PM by mr2madlad

daman on Mon June 29, 2009 7:12 PM User is offlineView users profile

Quote
Originally posted by: mr2madlad


1 how do you interpret / read the manifold gauges? Very basic question but apart from the pressure markings I have not got a clue.
in short presure reading is really all you need to understand,what applys to your carft>

3 how much R134a do I use? (Did find a PDF on this forum that said I need 25.5 Oz so I guess that’s sorted.
if 25.5ozs if factory spec thats what you useft>

4 will the leak dye and oil still left in the system be ok as none came out with leak or do in need to inject new once vacuumed out?
if none came out with leak you should be fine,nothing neededft>

5 will vacuuming it suck the oil and dye out? NOft>

6 Ambient temperature? Air temp before starting, general average air temp? yesft>





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'99 Chevy 4x4 Z-71 5.7 Vortec v8 CPFI
'97 Chevy 4x4 6.5 Turbo Diesel 2500
'95 Pontiac Grand Am GT 3100 v6 SFI
'88 Chevrolet Camaro IROC 5.7 TPI(49,000 original miles)

94RX-7 on Mon June 29, 2009 7:36 PM User is offline

Quote
Originally posted by: mr2madlad
I am pretty confident in doing this myself, so is it just a case of vacuuming it out, holding vacuum to see if it leaks and if not sticking 25.5 Oz back in the low side (high side closed off) and it will work?


In addition to the above, you need a new receiver/dryer.

Also, how many microns will your vacuum pump pull down to? Ideally it should be rated for 100 or less.

There should be a sticker on the car that tells you how much refrigerant the system takes...I would trust the amount on the sticker before I would trust what some random internet PDF says.

You can find info on how to interpret gauge readings all over the internet. I won't go into it here since it is sorta detailed.

Edited: Mon June 29, 2009 at 7:40 PM by 94RX-7

Peter_Coll on Tue June 30, 2009 9:32 AM User is offlineView users profile

Before you begin, you need to think about why the condensor burst. I would question if super glue will hold against the pressure when you recharge it. Finally, It may have been less costly to take it to a low end
AC service place where all they do is suck it out and fill it up.

Karl Hofmann on Tue June 30, 2009 2:45 PM User is offlineView users profile

Peter, He has replaced the condenser... a 15 year old condenser in the UK is rare indeed, the road salt, road compost and lousy weather ensures a short life

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Never knock on deaths door... Ring the doorbell and run away, death really hates that!

mr2madlad on Thu July 02, 2009 4:14 PM User is offline

Hi

All done, it’s up and running again, the front bumper had to come off to get to one of the condenser pipe work joints, that took 2 hours with rusty bolts that rounded off!

Old condenser fell to bits once off the car.

While I was in the mood of stripping things I removed the evaporator and bunged 2 rubber bungs in the open pipe work and evaporator then jet washed it, these cars do not have a pollen filter and it was crammed with leaves, feathers, mud (from rotten stuff) and loads and loads of dust, you could not see though it, now I can.

Stuck it all back together.

Pulled a 30hg vacuum for just over half an hour and then closed off both high and low side on manifold, left for 20 mins and it was still there so no leaks.

Purged the charge line and stuck 2 cans (340ml 12.2 ounce each) of new virgin R134a in the system from low side only, if I go by the 25.5oz from the PDF offered on this forum it needs a little more about an ounce or so, I am still trying to find out from Toyota the correct amount so will leave at that for now, seems to be pretty darn good.

Ambient air temperature 29 deg C (84 deg F.)

Watched the high side gauge go up to and stay at 191 PSI, and the low at 33 PSI, system running fine, the air is ice cold in about 20 seconds now and is at 5 deg C (41 deg F.)

I believe these are good readings, are they ?

In the UK down south (Brighton) we have had a mini heat wave where air temperatures otopped 31 Deg C with high humidity have been reached today, so the cool air is very well received at the moment.

Thanks for all the help

mr2madlad.


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The man who makes things, or breaks things, you decide.

Voyager97 on Thu July 02, 2009 4:52 PM User is offlineView users profile

My old book of A/C data gives a qty of 1.61 lb or 25.76 oz for the 1994 MR2.

Same book gives operating pressures of 18 - 36 psi low side, 199 - 228 psi high side. Those are at 80f ambient, so you probably need that extra oz or so.

P.S. ambient temp should be taken at about 2 inches in front of the condenser, as that will be the temp the condenser is feeling.

P.P.S. 31 deg C - call that hot ? Hit 33.2 here today (ooop north).



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Vic @ Pennine AutoChill

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