Very weak ac performance golf mk3 tdi

alghamedGT

Well-known member
Joined
Dec 10, 2023
Location
MOROCCO
TDI
GOLF MK3 AHU
Hi folks its summer time
I noticed that the ac performance is weak so the first thing i suspected is low refrigerant
Indeed
I got the car inspected in a professional ac shop
I found that the ac has 490g of refrigirant
We vacuumed it and put 700g of r134 thats what the factory recommended for mk3 golf
But nothing changed
Infact it got worse especially in highway driving it has very very weak cooling but it get better when i stop the car
When touching the return pipe its cold but when touching from after the reciever drier it's warmer i don't know if thats normal

I also suspected that i have too much refrigerant but the fans stops from time to time so i dont think i have too much high pressure

So guys any clues ?
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
I'm thinking that air doors are leaking warm air where you don't want it. Don't worry about coolant in the pipes. It changes temp along the way and can get pretty hot.
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
Maybe I shouldn't ass ume a shop that knows enough to suck it down and recharge by weight would also run it.

How about it algha... what did he do in total?
 

valvecrusher

Veteran Member
Joined
Feb 27, 2008
Location
DosCirclos
TDI
'96 Passat, '00 Jetta
So guys any clues ?
Hello from USA, North Carolina where it's hot and humid enough for dinosaurs to return and thrive.
I hope you stay cool in Morocco!


I think your problem is related to 'Blend doors' foam failing.


Google VW foam blend doors,
'Jetta Blend Doors' on Youtube, and also multiple threads here on TDIclub.
 

alghamedGT

Well-known member
Joined
Dec 10, 2023
Location
MOROCCO
TDI
GOLF MK3 AHU
In morocco my city fez temperature in the summer can get to 45°c (113°F)its important to have a working ac to not die

I did test the pressure and it's seems fine 3-4 bar (30-35 psi) in low pressure side and in the high pressure side 13-15 bar (200-220psi)

The testing was done in a cold day

And again the restriction valve high pressure side is not hot at all the return is slightly cold
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
So you had the refrigeration system checked out and it's ok.

System works better at a stop.

At a stop there's no hot air blowing through the car from it moving.

Sounds like air doors leaking warm air from the outside like I said in my first post. You have 25 year old foam seals that are known to fall apart. is there a reason you're resisting this?
 
Last edited:

alghamedGT

Well-known member
Joined
Dec 10, 2023
Location
MOROCCO
TDI
GOLF MK3 AHU
So you had the refrigeration system checked out and it's ok.

System works better at a stop.

At a stop there's no hot air blowing through the car from it moving.

Sounds like air doors leaking warm air from the outside like I said in my first post. You have 25 year old foam seals that are known to fall apart. is there a reason you're resisting this?
i dont feel any hot air coming from air vents when i switch off ac
and now after 1500km of driving the ac is very weak even in idle
i doesnt cool at all and because its my daily drive now i open my windows to get fresh air
 

valvecrusher

Veteran Member
Joined
Feb 27, 2008
Location
DosCirclos
TDI
'96 Passat, '00 Jetta
@alghamedGT

we are trying to explain....


Deep behind the radio,
there is a box that controls where the air comes out--panel, floor, defrost/windshield.......
this box also controls hot(heat), or cold air(AC) as well....

This box controls flow of air by moving metal panels to block and divert heat and cold AC, depending on your selection.


VW made these Metal Panels with HOLES, and then covered the panels with thin foam layer......
a Mk3 is 25 years old and your foam is long gone with the ancestors by now......leaving the HOLES.


You must disassemble your car to cover the holes,
cover the holes IN the METAL PANELS,
with aluminum foil backed High Temperature Tape, for HVAC.......


Let me guess, when you change from floor, to panel, to defrost,
the air doesn't move from section to section very much,
but it comes out them all just a little bit?


on youtube, enter
Mk3 Jetta blend door repair.

I had trouble, Youtube re-launched or something a whole new format and i can't find 'share this video'...
 

alghamedGT

Well-known member
Joined
Dec 10, 2023
Location
MOROCCO
TDI
GOLF MK3 AHU
Thanks guys i understand that metal flaps can cause problems and im planing in the future to repair it but i dont think thats my problem because everything is working properly with very little air leak
Defrost work floor work panel work

no heat escaping from from vents

And Now after 1500km of driving it doesn't cool anymore very very weak even at idle
Even in cold morning with engine is cold
I can feel the ac compressor is running fans dont work a lot and the ac bearly cools

The shop told me that thermal expansion valve is bad because the high pressure side is not hot in the txv
 

valvecrusher

Veteran Member
Joined
Feb 27, 2008
Location
DosCirclos
TDI
'96 Passat, '00 Jetta
i understand.

If you can, reach into your car, under the dash and find the selector box, with the panels inside.

If you can get your hand on it, is IT cold? Then your AC is not able to deliver the Cold Air, since it is mixing with the warm outside and and also the heated air from the heater core.

These panels separate and control delivery of all air handling functions.

When this problem arises,(and it ALWAYS does....look how many VW owners have this issue), the air is not colder than outside air, mised with heated air.
When it's cold out, the cold air blends with the heated air from tghe heater core.

So at no time do you get Full Cold, or Full Hot.......it's always a mix, thus lukewarm air in winter, and warmish cold air in summer...
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
If you know you still have AC system problems why are you trying to convince us of that? Get them fixed. They may not be cheaper to fix but they sure are easier.

Maybe your air box problems aren't too bad.
 

garciapiano

Veteran Member
Joined
Feb 12, 2018
Location
Los Angeles
TDI
1997 Jetta TDI (1Z)
Sounds like blend doors (cheap but painful fix?), but could be something else. These cars are around 30 years old now, and a lot of them have shot components... As far as what I've learned as far as AC stuff goes I have a few rules:

1. Replace all components (maybe excepting the lines) when one fails.
2. Buy the best OEM parts you can (see rule #1)
3. Get it serviced by a professional (because of the expense of rules 1 and 2)

Rebuilding the heater box is not something I would even expect most shops to want to do, it took me DAYS to do mine (although I was being very slow and thorough). Labor cost would easily total the car.
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
Reminds me of the dash in my '98 Dodge. Had a single crack but when I had to do the leaky heater core it came out in crumbs. Two day job to put it all back in. True I'm not the most stick to it type of guy but still...

At least there's a high quality replacement available.
 

thechoochlyman

Vendor , w/Business number
Joined
May 7, 2015
Location
Campbellsville, Kentucky
TDI
1997 B4 Sedan
Reminds me of the dash in my '98 Dodge. Had a single crack but when I had to do the leaky heater core it came out in crumbs. Two day job to put it all back in. True I'm not the most stick to it type of guy but still...

At least there's a high quality replacement available.
I did the AC condenser in my '99 a couple of years back. The dash was already in pieces, I basically only had to do half the job because there was nothing left to put back on top. lol
 

alghamedGT

Well-known member
Joined
Dec 10, 2023
Location
MOROCCO
TDI
GOLF MK3 AHU
thanks guys for the effort
i found that my problem is the compressor
i tested with a used thermal expansion valve no improvement
the shop tested the ac pressure in a very hot weather today was 40C° ( 104F°) and we found out that its too low
so i bought used one from junk yard
now ac is ice cold im very satisfied with the performance

of course i will repair my blend doors soon its a must do thing
thanks again
 

Rig

Veteran Member
Joined
Apr 14, 2010
Location
New Mexico
TDI
1998 Jetta TDI, 210k miles
I can tell you that my blend doors are totally shot. All the foam blew out long ago. I've never taken the dash apart to fix them. My AC blows nice and cold. I live in NM so it's regulary in the 90s.

Based on what you described i would have guessed the compressor.
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
There's that gizmo in the head that controls the displacement. Can't remember what it's called at the moment but might have been that.
 

alghamedGT

Well-known member
Joined
Dec 10, 2023
Location
MOROCCO
TDI
GOLF MK3 AHU
Thanks guys now i have very good ac but i have another problem
To day in highway driving the ac performance got slightly weaker when i put the fan speed in 2 and when i stopped the car i found that the ac return pipe is white with snow so i stopped the ac and the car has drained too much water from condensation
Is that normal or something is not working properly?
 

alanack

Veteran Member
Joined
May 10, 2022
Location
Rhode Island
TDI
1998 Jetta
Thanks guys now i have very good ac but i have another problem
To day in highway driving the ac performance got slightly weaker when i put the fan speed in 2 and when i stopped the car i found that the ac return pipe is white with snow so i stopped the ac and the car has drained too much water from condensation
Is that normal or something is not working properly?
I'm having the same problem see my thread.
 
Top