My 98 v70 awd has a slow AC leak. I filled in July and my daughter informed me that it’s not working. It there a leak-stop product that might work? I am trying to avoid dumping money into this 22 year old car if I can avoid it.

Welcome to the club. The leak usually happens in the evaporator, sometimes a receiver/drier, and rarer still a bad Schrader valve.

Teach your daughter how to add a can of r134a. Less than $25/year beats tearing out the dash to replace the evaporator. At least until the AC only lasts a week or two.

The book rate for replacing the evaporator is 8 hours, IF you can find someone willing to do it.

There are plenty of stop leak products available, but most shops won't want to use their equipment to evacuate and vacuum it afterward, as it tends to clog the filters on their machines and the filters are expensive.

Do you know where it leaks from? The evaporator is a likely candidate. Mine has a slow leak. It is often most cost-effective to get a fill hose with a gauge and add r134a yourself as needed. Many of us need a can per season.

I recently had to replace the accumulator on mine, which had rusted out. It is worth sorting out where the leak is-- some fixes are pretty cheap.

I agree. I have a slow leak too. Try refilling with a 134a can with gauge. I have refilled the AC myself the previous 2 years on my 2002. I used AC PRO and interestingly enough I didn’t have to refill the AC this year. AC PRO and other high quality AC products have a sealant added. Apparently the sealant worked...:)
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Will I buy another Volvo??? We'll see....