Mediocre AC 1997 850 Base

BrandonRoberson · Post by **BrandonRoberson** » 18 Jul 2025, 14:02

Hello all,

I bought my 850 just a few weeks ago. One owner old lady car with 230,000 miles; has only been driven about 100 miles per year for the last decade and has had a refrigerant leak for about 5 years. I added refrigerant up to about 45psi on the low side with the compressor running. The AC is working, and the gap on the compressor seems fine because it continues to run, but I am only seeing about a 15 degree temperature differential from the middle vents (both of them) at idle; 20 degree at 2500 rpm. Radiator fan is running, AC is set to max, recirc, air mix at minimum. Outside temps here in Indiana are about 85F with 70% humidity.
Shouldn't I be seeing a 35-40 degree temperature differential at a stop?

Post by **matthew1** » 18 Jul 2025, 15:11

Welcome to MVS. Hot cold diverter door stuck maybe viewtopic.php?p=613629#p613629

BrandonRoberson · Post by **BrandonRoberson** » 18 Jul 2025, 16:01

Thank you for the welcome! After 4 years of 240 dailying, I'm excited to try out the 850 world. Particularly the part about decently modern air conditioning...

Maybe I'm confused. Wouldn't that exclusively effect the engine intake air, not the cabin air temp? Also, mine failed at some point already and the PO had it zip tied in the cold air position anyways, so no hot air intake there.

Vova585 · Post by **Vova585** » 18 Jul 2025, 22:21

1. Check condition of cabin air filter. If the PO was using zip ties, he(common, show me that 1 lady owner that woukd use zip tie on hot/cold door) likely was treating everything else with "respect ".
2. Check condition of the ac condenser(ac radiator). If packed with dirt/bugs- will need to be washed to have good airflow.
3. If the system was "flat" and moisture entered the system..without proper diagnostic of where it was leaking, flushing the system from contaminants, replacing dryer, and refilling the system- it would be hard to expect great results.

BrandonRoberson · Post by **BrandonRoberson** » 19 Jul 2025, 07:06

1. I will check the cabin air filter today. PO was an older woman whe had owned it since new. I have paperwork to show that all the work was done by various shops, so someone at one of the Indy shops did it. I’d have done the same, it’s not really neglect to disable a common, potentially harmful failure point on a 25 YO car.

2. Condenser is in remarkably good condition for the mileage. Very few dents and definitely allows good airflow.

3. This is what I started thinking about last night. Lots of refills without proper purging of fill lines could have added up to a lot of air/moisture in the system. I went ahead and ordered a new drier and plan to vacuum down the system and do a fresh refill. I’ll update when I get that done.

BrandonRoberson · Post by **BrandonRoberson** » 19 Jul 2025, 07:09

matthew1 wrote: ↑18 Jul 2025, 15:11 Welcome to MVS. Hot cold diverter door stuck maybe viewtopic.php?p=613629#p613629

Also, I realize maybe you meant the hot/cold airflow flap in the climate control system. I had considered that, but figured that was probably functioning fine, since with the AC switched off, the vent temp matches the ambient air temp. Please correct me if this logic is flawed.

Post by **scot850** » 19 Jul 2025, 08:27

Being an 850, it may not have a cabin filter! If not, one from the V/S70 can be fitted by pulling the holding frame from a junkyard.

Neil.

Post by **abscate** » 19 Jul 2025, 09:41

If you need a frame I have spares.

You should get 35F delta in recirc mode, fan speed 3-4, 2500 rpm after 5-10 minutes.

These AC units are powerful and work well at correct charge. Vacuuming, pumping down for 1 hour, then two cans 680 grams should get you there. A bit undercharged in hot climate, a bit overcharged in cold climates

BrandonRoberson · Post by **BrandonRoberson** » 19 Jul 2025, 14:49

scot850 wrote: ↑19 Jul 2025, 08:27 Being an 850, it may not have a cabin filter! If not, one from the V/S70 can be fitted by pulling the holding frame from a junkyard.

Neil.

Yep! I knew there was a chance and sure enough, this one never had an air filter.

BrandonRoberson · Post by **BrandonRoberson** » 19 Jul 2025, 14:52

abscate wrote: ↑19 Jul 2025, 09:41 If you need a frame I have spares.

You should get 35F delta in recirc mode, fan speed 3-4, 2500 rpm after 5-10 minutes.

These AC units are powerful and work well at correct charge. Vacuuming, pumping down for 1 hour, then two cans 680 grams should get you there. A bit undercharged in hot climate, a bit overcharged in cold climates

Thanks! I’ll try to reach out about the frame in a few weeks. I’ve spent enough on parts this month already lol.
I’ll plan to do this procedure when the new drier I ordered comes. I’ll come back and update with the delta afterwards.