97 850 GLT A/C Doesn't Work - where to start

[combatkarl]

Hi All,
This site continues to amaze me with the knowledge and advice that is found here. I'm following the lead of rmmagow and asking springtime A/C questions, but likely need more help than him - https://www.matthewsvolvosite.com/forums ... 05#p323305
So, I've had this 850 for ~1.5 yrs and I knew the A/C didn't work when purchased.
Where do I start the diagnosis/fixing?
1. A/C clutch/compressor doesn't engage. Briefly tried tapping the compressor w/ broomstick.
2. ECC lights flashing. Will be building the "decoder" thanks to jreed.
3. Is there an "easy" way to tell if evaporator leaks?
4. Should I attempt recharge with DIY freon?
Thanks everyone.

[cuhfs]

Here's what I know:
1.)no answer to items 1 & 2 except you should know that without freon in the system AC clutch/compressor wont engage.

#3 you can use a A/c dye tester to see if there is dye by the firewall at the evap connections. The dye tester at Harbour freight is not too bad. maybe amazon too but not sure
#4 WHy not? it dont work now anywway.

[volvomadness]

Easiest is go to a garage with a fully equipped machine. The machine test the system first and then will identify if and where a leak is. A can of freon will cost about $40 my service station has a machine and he will charge $80. If you use the can an it leaks out then you are out $40.

[joe_pinehill]

Easiest is go to a garage with a fully equipped machine. The machine test the system first and then will identify if and where a leak is. A can of freon will cost about $40 my service station has a machine and he will charge $80. If you use the can an it leaks out then you are out $40.

I agree, unless your experienced with AC, I think in the long run your are better off taking to a garage. I tried the repair trouble shooting route on a Jeep, in the end i spent more. AC work isnt high tech, but it requires expensive specialized equipment.

[cn90]

1- With engine off, pressure on the low side should be 90-100 psi. If not, you have lost some R134a.

2. Search forum for "AC Clutch shim". Options:
- bread clips (I prefer not to use this trick)
- zip ties (this is what I am using).

[abscate]

If you have other older cars, it might pay to buy the stuff needed. Harbor a Freight will sell gauges and pump for under 200 usd for example. It's really good practice to pump down the system to keep parts from corroding as opposed to just "topping off" with refrigerant

[combatkarl]

Thanks all. I've got to prioritize my maintenance this spring and the A/C may have to wait. I've got brakes and likely suspension to update.

[scot850]

I agree with what everyone has said. If you want to know if the system is worth fixing, the only way to do that is to have it pressure checked and have a dye added, so if it leaks down again you know what needs to be replaced. If it is minor then fix, but one major fail issue with these cars is the evaporator which is a dash out job. There is a very good write up on the forum which I used and it took a good couple of days, and a lot of care not to break anything. If you don't want to tackle this yourself, then leave it alone.

Neil.

[combatkarl]

I went with adding 18oz of R134a to get a baseline. Success, at least temporarily, A/C is cold and compressor functions. Since the compressor wouldn't cycle at all "freon" couldn't be added, I jumped the low pressure cycling switch as directed by the Haynes Repair Manual and jimmy57 in this post https://www.matthewsvolvosite.com/forums ... ch#p249408

We'll see how long it lasts, but it is good to know the compressor functions. Now, I'll wait and see for the evaporator and other pieces. Thanks

[abscate]

Harbor freight has the manifold set on sale for 60 USD