2000 V70 AC recharging

Post by **jblackburn** » 22 Jun 2010, 16:59

Your clutch gap has gotten too big, and the clutch no longer makes contact once it warms up.

I believe the compressor on your 2000 is different than my 98 and the 850 series, but the same concept applies to re-shimming the compressor:

http://volvospeed.com/vs_forum/index.ph ... d828a0e2ef

http://volvospeed.com/vs_forum/index.ph ... ntry992918

adjulius · Post by **adjulius** » 22 Jun 2010, 21:10

It would be helpful to know exactly what a/c issues you're having.

If the system is VERY low on R134a, the compressor won't kick in, making the low-side pressure too high to charge. You need to find the low-side pressure switch on the a/c line up against the passenger-side firewall. Unplug the cable from the sensor embedded in the a/c return line. Then, with car running and a/c on, use a wire to connect the two electrical ports inside the cable that you just disconnected. This will bypass the low-pressure switch to command the a/c compressor to turn on despite being too low on refrigerant, thus allowing you to suck in the new R134a and charge the system.

The simple way to assess whether the a/c system has adequate charge is to look at the low-side pressure while the car is on and a/c running, set as cold as possible. With the adapter and gauge hooked up to the port just behind the passenger-side headlight, the pressure will read lower as the ambient temperature rises, but it should read over 30psi for sure. 35-40 is a rough target.

However, the more accurate way to charge is by mass of refrigerant. These cars call for 750 grams (28 ounces) of R134a. This ensures that you don't overcharge the system (which avoids the theoretical risk of damage). The perfect way to do this is to have a shop with HVAC capability to pull all the gas out of the system and pull vacuum, and THEN add exactly the amount of R134a.

The DIY cheap way is to evacuate the system (legally you should get this vacuumed out by a shop) until the psi is close to zero, and then add 28 ounces of R134a. It's relatively easy to find 14 oz cans, so if you buy two you're at the perfect amount.

Post by **JRL** » 22 Jun 2010, 21:31

Yeah, whatever.
You CAN charge an empty car from the low side with no problems whatsoever if you know what you're doing.
I just did with about 4 S/V70s or 850s.
Use a gauge and listen carefully to the compressor.
if it stops "clicking" it's full, whatever you do 2 cans of R134 is enough. If completely empty that's 24 ounces and it should work just fine, (the 4 oz. doesn't make all that much of a difference if nothing else is wrong).
The actual total is 1.65 lbs

adjulius · Post by **adjulius** » 22 Jun 2010, 21:57

"Yeah, whatever"? Not the best way to approach Volvo maintenance or recruit forum contributors. I was merely summarizing a wide collection of posts that I've read on the subject. Sorry for trying to help.

Post by **JRL** » 23 Jun 2010, 05:07

Of course if everyone had the money the way you stated is the correct way, but at over $100 a pop it can add up.
Most people that buy these older cars now don't have that kind of money to spend to do this every time they have an AC issue.
You can buy a guage which shows pretty much how much you have in the system and once you know the trick and feel of adding R134, it's pretty easy.
Can you make a mistake, sure, but at least one can find out if his AC is working at all. Then they can decide whether to take it to a shop to evacuate the system and add the exact amount, 1.65 lbs

Retired MVS Contributor · Post by **Retired MVS Contributor** » 23 Jun 2010, 06:51

What kind of service port quick-isconnect connector do you have?...It sounds to me like the Shrader valve depresser pin in the quick-disconnect is not depressing the Shrader valve in the service port...The Shrader valve looks like a tire valve and is down inside the service port...If this is the case, DO NOT!!! heat the can, it could explode because the pressure in the can will go 'way up and there is no where for it to go...It should flow into the system...See if you can borrow another quick-disconnect...

When the can is cold, refrigerant is being dispensed...You should not remove the can until it warms back up...That is when the can is empty...It is the refrigerant leaving the can that makes it cold...I am not a big fan of the "side-of-the-can" can taps...You have to empty the can...With the top-of-the-can dispensers you can close the valve and save the remaining refrigerant for a rainy day...

Post by **JRL** » 23 Jun 2010, 07:19

We agree to disagree.
I did not say HEAT the can, I said warm it up a little by sitting the can in a bucket of LUKE WARM water, like 70 degrees.
This way it will dispense in about 5 minutes, cold it can take up to half hour, if at all!

BTW this was learned by a very good Volvo tech who is a person who has been a general mechanic for over 35 years

Retired MVS Contributor · Post by **Retired MVS Contributor** » 23 Jun 2010, 07:27

He is in the business for about the same amount of time I was, but I retired in 1993...Still does not make either one of us a genius...

Post by **jblackburn** » 23 Jun 2010, 07:44

*sigh*

Lets all agree to disagree. No one here is a genius, and no one here is an idiot.

The can in slightly warm water trick does work, I have done it myself. It's not going to explode unless you set it on fire or put it in 100+ degree water - I keep a can of it in my spare tire well, and it hasn't blown up. But this is besides the point.

Problem is it blows cold for like 2 minutes and then gets warm. The can wasnt freezing up--- it wasnt even going in from what I could tell.

If the AC works fine for a few minutes and the compressor is not clicking in and out every few seconds, your system is charged fine and you need to start looking at the clutch shims and/or thermal cut-out switch. If, on the other hand, you still hear the compressor running but aren't getting cold air, something (probably air) has got in the system & is freezing up and you'll need to have the system evacuated & recharged and replace your receiver/dryer.

Retired MVS Contributor · Post by **Retired MVS Contributor** » 23 Jun 2010, 10:29

I do not know where this "clutch shim" thing came from...If the clutch IS engaged but not turning due to too big a gap, it will be slipping, overheating and burning due to friction...If it NOT engaging, it is an electrical problem and has nothing to do with the gap...Electricity engages it, not the air gap, and there are other reasons such as over-pressure, under-pressure, defective swithches or thermostats, etc that are not allowing electical power to reach the clutch...The original post on another forum for fixing the clutch gap is very good, but some of the fixes put forth for the porpose of avoiding all the work involved are very dangerous...

The static pressure of R-134 remains close to being equal to ambient temperature regardless of whether it is in the can or in the system...If you know what the ambient temperature is, you have a pretty good idea of what the pressure in the can is...Putting a can into 70 degree water when the ambient temperature is 90 degrees (the pressure in the can is already 100 pounds) will not raise the can pressure, it will lower it by reducing the can temperature from 90 degrees to 70 degrees..It needs to be heated to a higher temperature than ambient in order to boil the liquid off to a vapor in the can...This will raise the pressure in the can and push refrigerant into the system...The point is to make sure that it has a way to leave the can and not over-pressurize it...

Getting the can hot while it is still sealed is playing with fire...Cans that were sitting under heat registers have exploded on the shelf in stores...On summer days in New York I have seen 140 degrees inside my car...It's got to be a LOT hot than that in Forida...Thats not a safe place to keep ANY pressurized can, be it refrigerant, paint, or a Bernzomatic...