Where is the High-Side Service Port Located?

SWTomlinson · Post by **SWTomlinson** » 11 Jun 2011, 16:48

I'm working on the vehicle of a friend of mine. It's a 2000 (?) Volvo V70, L5 2.4 Air Conditioning System.

I'm not 100% sure that it's a 2000 Year Model, but the Manufacturer Date is 11/99, and there is no Vehicle Emissions Control Information Label on the inside of the Hood or the Engine Compartment to help differentiate as is the case with the majority of other OBDII Systems in the current market.

However, the Repair Guides I use indicate that procedures are the same on all U.S. and Canadian models of Volvo Cars 1999-2005. (Too, I understand that there are times when information such as this is erroneous.) The 10th digit of the VIN is 'Y' if this helps (YV1LW61J4Y2687242).

The problem is that the Compressor shuts off intermittently after running for a while, and the system then blows warm air [of course]. Then, after a little while longer (times vary) the compressor will come back on, and the System cools sufficiently.

I found the Low-Side Service Port down next to the High-Pressure Switch, hooked up my Gauges, and the reading is 55 psi @ Engine Idle (clutch-engaged). The Low-Side then pulls down to only 35psi @ approximately 2000 rpm, which indicates to me that the system is over-charged.

However, I really do prefer to be positive about this by being able to monitor the system performance simultaneously from the High-Side Service Port, because the Orifice Tube may in fact be clogged instead of the System being over-charged . . . provided there is an Orifice Tube (no Expansion Valve shows up in Parts Listings).

On a day such as it's been today, with the Temperature & Humidity Mild/Low, the Low-Side should have pulled down to any where between 15-24 psi.

I've looked all over the Firewall from where the Evaporator Lines come out, all the way down the P/S Wheel-Well Frame to the Receiver/Dryer & onto the left side of the Condenser, to the right side (D/S) of the Condenser, and back to the Compressor . . . and all the way back again. I've done this twice.

Still I cannot find the High-Side Service Port.

Can anyone help? I would greatly appreciate it.

Thanks.

SWT

Post by **misha** » 11 Jun 2011, 17:04

I'm not 100% sure but i think that these cars don't even have high-side service port.It's only low side behind passengers's headlight.

Wait for somebody else to chime in,but i'm preety sure that they don't have it.

Almost forgot...It's normal for these cars that ac compressor cycles on & off.It's NOT normal to cycle on & off frequently(every few seconds).If it does it frequently that means the system is low on freon.

SWTomlinson · Post by **SWTomlinson** » 11 Jun 2011, 17:32

@ misha:

I agree that on/off cycling normally indicates a low charge; however, not with a 55 psi Low-Side reading. Don't you agree?

Additionally, I found at . . . https://www.matthewsvolvosite.com/forums ... =9&t=37773 . . . in jimmy57's reply to Marlin on 30 Mar 2011 reference partial but similar circumstances that the High-Side Service Port is located next to RH hood latch . . . that the cooling duct for module box may be in the way.

I do appreciate your reply though. Really!

Thanks.

SWTomlinson · Post by **SWTomlinson** » 11 Jun 2011, 17:33

I apologize. Somehow I double-posted this reply.

Post by **jimmy57** » 11 Jun 2011, 19:22

You unscrew the high side pressure sensor, provide electric fan air flow to condenser and use an Acme thread R134a line on the Schraeder valve fitting where sensor was unscrewed.
If the car was still hot inside the 35 psi reading is not high as CCOT having no regulation of refrigerant flow, runs low side pressure directly related to evaporator temp unlike TXV systems. Try with fan speed one step below full and recirc inlet air selected.
Shutting down on P80 platform Volvos is almost always compressor high temp sensor kicking out from low charge not providing any chilling at the compressor head from low side evaporation continuing to that point or the compressor clutch gap being too wide and when pressostat opens circuit and then closes again the magnetic coil has inadequate force to pull in driven plate. Hot clutch magnetic winding has lowered force as compared to the winding with lower temp.

SWTomlinson · Post by **SWTomlinson** » 12 Jun 2011, 07:22

@ jimmy57:

I appreciate your response. Now I have to procure an Acme-Thread R-134a Fitting to put in place of the High Pressure Switch on High-Side. A fellow Technician I used to work with suggested the same thing a couple of hours ago. Thanks! You fully qualified what he had suggested.

This of course is new to me as I have never come across such a procedure while doing AC System Problem-Diagnosis, Service, or Repair on any of the Big-Three U.S. Auto Makers or any Asian Import. So, that answers the question as to why there is no High-Side Service Port!

Too, my Volvo AC Systems experience is limited to that of the A25 & A30-Series Off-Road Articulated Dump Trucks, and the L60F & L70F-Series Wheeled Loader. These are very good Systems . . . IF you can keep the Operators from stepping on the Heater Control Selector Valve Component Cable when they do their Pre-Operation Maintenance checks in the morning, and if you can keep mud out of the Condenser. Additionally, these Systems always had Low & High-Pressure Service Ports. So, to say the least, I was stumped. Again, Thanks!

However, I do have another question or two.

One: Can you tell me what Year Model this Vehicle in ('Y' in tenth digit of VIN)?

Two: Reference the portion of your reply in paragraph 2 . . . The System was still cooling sufficiently @ approximately 2000 RPM. The Clutch was still engaged---with the System still cooling. However, when the inside of the vehicle was hot, the compressor was shut down, and the system equalized @ roughly 95-98 psi.

To my understanding a System NOT over-charged should pull down much lower than 35 psi. And with today's Temperature/Humidity Levels being relatively mild, I don't see how this apples. But pulling the fan speed down [with Recirculation selected] makes a lot of sense if Ambient Temperature and the resulting corresponding High Pressures are related to the on/off-cycling of the System. Do you see my point? Or, perhaps you can provide me with a little more insight into the Theory & Operation of the P80 Platform?

Three: This being a Cycling Clutch Orifice Tube System and not TXV, can you tell me where the Orifice Tube is actually located? My Repair Guide is so limited where the Volvo is concerned . . . hardly any information to guide through the process at all, i.e., no specifications as to Oil/Freon Capacities, Service Port, etc.

To the points you make in Paragraph 3: I’m also going to look into your suggestion that the Clutch Gap may be too wide. My visual inspection suggests that it probably is. However, if this does not remedy problem, then your conclusion is that the System is Under-Charged. Am I correct in this conclusion?

Thank you, jimmy57. I appreciate it.

SWT

Post by **misha** » 13 Jun 2011, 14:36

SWTomlinson wrote:..I’m also going to look into your suggestion that the Clutch Gap may be too wide. My visual inspection suggests that it probably is. However, if this does not remedy problem, then your conclusion is that the System is Under-Charged. Am I correct in this conclusion?

Yes...

If system have proper level of refrigerant and compressor still cycles on & off,then the problem is in clutch gap.If clutch gap is ok and compressor still cycles on & off,then system is undercharged.

Note that compressor cycling in these cars is normal even if system is properly charged.But at the other way if it cycles on & off rapidly(in about 2-3 seconds)that indicates the system is low on freon.

Cycling for about 4-6 times/minute is ok.

I bought my car almost new with 69k km and compressor always cycled on & off frequently.I didn't notice this cycling in any other car when ac is on.However...factory freon lasted 11 years.

First time i needed to recharge ac system was 3 years ago.

Post by **JRL** » 13 Jun 2011, 15:12

You have a 2000

SWTomlinson · Post by **SWTomlinson** » 15 Jul 2011, 21:57

Thanks everyone.

Turns out that the Air Gap was too wide at almost 1.4mm. She couldn't afford the $460.00 price for a new Clutch and Field Coil, so I removed the Clutch Plate (no shims). I then carefully removed material off the end of the Compressor Shaft with a Carbide Rotary File and reinstalled with one shim. Resulting Air Gap was 0.25 mm.

Added a 4 ounce charge to get pressures up now that I'm somewhat more-educated on this Platform.

She reports that it has been cooling fine ever since.

I appreciate it.

mattwebb502 · Post by **mattwebb502** » 25 Jul 2013, 17:48

jimmy57 wrote:You unscrew the high side pressure sensor, provide electric fan air flow to condenser and use an Acme thread R134a line on the Schraeder valve fitting where sensor was unscrewed.

Anybody care to tell elaborate on this?

I'd prefer an adapter rather than a hose...

anybody have a link for what one needs to buy?