Volvo V50 2011 very high vibrating highside pressure

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Swedal
Posts: 16
Joined: Fri May 26, 2017 2:30 am

Volvo V50 2011 very high vibrating highside pressure

Postby Swedal » Mon Oct 19, 2020 5:26 am

This Volvo was low on refrigerant so I pulled a good vacuum and started recharging. At 370 grams of 535 grams total charge I saw the highside at 24 bar (360 psi) with ambient temp at 8C (or 45F). Way too high. Needle was vibrating abnormally at that reading. Suction pressure was normal but was creeping up due to high discharge. Not pulsating like highside though. I stopped recharging at that point. Highside port use to be really hot at those pressures but it felt cold. There was no liquid to suck back into lowside either but that might be due to not fullt charged? Where do I start? Am I looking at a restriction in condenser? Another "expert" guessed it was a clogged orifice tube.
Al9
Posts: 225
Joined: Tue Mar 10, 2020 3:26 am
Location: Southern Europe

Re: Volvo V50 2011 very high vibrating highside pressure

Postby Al9 » Mon Oct 19, 2020 8:41 am

Sanden SD7V16 (or PXV16) compressor? If it's this one, i think it's supposed to fully destroke once a restriction keeps enough refrigerant from flowing around.
Swedal
Posts: 16
Joined: Fri May 26, 2017 2:30 am

Re: Volvo V50 2011 very high vibrating highside pressure

Postby Swedal » Mon Oct 19, 2020 3:15 pm

Yes its the SD7V16. So what you say is that it should do the opposite when restricted? Pump less. So why does it behave like this you think? Is checking the orifice for clogging worthwhile? My plan was to throw away the front end to get some access and feel around for where things change temps. Any idea for why it pulsates in pressure? Like 10 psi up n down quickly.
Al9
Posts: 225
Joined: Tue Mar 10, 2020 3:26 am
Location: Southern Europe

Re: Volvo V50 2011 very high vibrating highside pressure

Postby Al9 » Tue Oct 20, 2020 1:38 am

A severe oil overcharge can make the condenser completely useless (internally coated/pooled with excess oil to the point of being unable to exchange any heat). Still, checking if the orifice tube looks dirty is a great way to check for compressor wear (abuse creates serious wear), keeping in mind that most of the wear material will be lodged inside the condenser (MCX parallel flow design on modern cars). No idea as to why it's pulsating.

Make sure there's enough airflow through the condenser. I've witnessed a weaker than normal cooling fan motor being enough to create compressor noise once the thermostat opened and the radiator (placed right behind the condenser) heated up. Both side gaps between the condenser and the radiator were sealed with weatherstrip foam too, yet the slight airflow reduction was enough to create problems.

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