BimmerFest BMW Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
198 Posts
Discussion Starter #1
E36 A/C is not strong enough and mechanic cant find leak before, so thinking of adding more 134A will be an easy task. Measure the temperature (70F) and add 2 cans (total 24oz, E36 has 36oz capacity) while compressor is running, the reading is around 30PSI.
But during hot afternoon, saw reading jumping between 35-red zone and as result compressor kicks in then stop, so no cold air and the no fan !!! Fuses are all good.
Rechecked in the evening (80F), everything works fine and reading is steady at either 22PSI or 30PSI (not sure why each time is different) when compressor kicks in. The reading is around 40-45PSI when compressor is not on.
I wonder if I over-charged A/C even the reading is below suggested value?
Why the fan is knocked out when a/c is not kicked in?
Thanks.
 

·
D'oh, You Kids!
1984 633CSi, 1985 635CSi, 1985 325e, 1987 325is, 1993 325is, 1995 318is, 1995 M3, 2003 F150
Joined
·
29,558 Posts
You've overcharged the system.

Paging drivinfaster....your A/C expertise is needed here.
 

·
Registered
Joined
·
12,382 Posts
the aux fan will kick on when the compressor spins to increase airflow to aid in cooling the refrigerant at the condenser. that is why the fan turns on/off with the compressor.

if it doesn't then that poses a problem.


as for the lack of cooling, there could be a few reasons for that. the most common is low refrigerant. how low?? who knows, nobody will be able to tell you for certain.

take that chart and throw it away. the first thing that you need to know is ambient temperatures will affect the cooling capability of any ac system, so looking at a chart is pretty much useless since it in no way is able to determine how low a system actually is.

here's what i suggest. reclaim the refrigerant, replace the accumulator, reseal the system; yes, all of the O-rings....they're ll the same age, or close to it, and if one has compressed enough to leak the others are not far behind.

then recharge with the correct amount of refrigerant.

check the temperatures at the vent on low, with gauge readings on the high and low side, and report back.


there's a write up about ac in the super sticky at the top. read that as well.




df
 

·
Registered
Joined
·
198 Posts
Discussion Starter #5 (Edited)
Thanks for the reply. The compressor engages and vent air is cool but not cool enough as original.
Why replace accumulator? Since I couldn't find it in the realoem diagram I don't know the part# and price. Doubt if reclaiming refrigerant and resealing and replacing accumulator is DIY I can do. So maybe refill every year is a cheaper option ?

EDIT: is the ambient temperature much higher than the weather forecast because it sits next to the firing engine?
Why does the fan go out even I over charged?
 

·
Registered
Joined
·
12,382 Posts
questions are pointless without readings...


do this, ok?? go get an infra red temperature gun, available at lots of places. take a reading of the engine bay and the gauge at res should be about tat.

if you do it first thing in the morning, for instance, and the ambient temps are 85 degrees, then the resting temps should be about 85 psi. on an engine bay that is already up to operating temps, a higher reading for the resting state would be expected. how much depends on the temp of the engine bay. hence the reason for the non contact thermometer.




df
 

·
Registered
Joined
·
198 Posts
Discussion Starter #7
Sorry for late update.
Infrared gun reads 110F and a/c pressure reads 22PSI when compressor is on and 35PSI off. I couldn't make compressor idle long enough to let reading slide to read zone. I guess I will let it be until the problem becomes easier to replicate. I will consider replacing accumulator when the problem becomes more severe in the future.
 
1 - 7 of 7 Posts
Top