inactiveuser1

Had the dealer put new hose on and convert it to R134 at the end of May 2008.Now sounds like the compressor clutch is constantly kicking in and out even the tach will float up and down like a drag on the motor which it must either be low or compressor going.
So would like to know which side is low so I can ad some over the weekend to see if it works.I see the one at the front of the car and the one at the rear with blue cap
Anyone have picture of which to fill at alot easier to see pict would help alot more!
1987 928 S4
Thanks,
Mark

inactiveuser1

To make it easier to ask question on the air recharge I will attach pictures.
The very front of car wanted to know if thats the low side.
Also someone talked about jumping wires to get compressor to work
are they talking of #1 and #2 or
the area were the plug is marked #3
Before I stick the gauge on wanted to make sure that was the low side marked in.
The site glass at this pint is clear.
Mark

Tampa 928s

Mine is an 86 and looks different and that is the location of my high side.
The low side on mine is under the A/C hoses on the passenger fender wall and has a blue removable screw off cover on it. You have to look and feel for it but I think that is your low side. Not sure but that maybe the temperature or pressure switch not sure for your year. The only time you need to bypass the switch if you are very low on gas and compressor will not turn on! See if the clutch engages and you should be fine.

Charley B

You say your compressor is kicking in and out, so you shouldn't need to jump the switch to charge.

I'm sure you're aware, but I believe on the '87 the position to the left end of your slider is for recirc. air and the compressor will activate in this position. At least it does in my '88.

dr bob

Don't add anything until you know that you are low on refrigerant. The pressure switch on the 928 is in the high side, so a cycling compressor clucth is likely not due to low refrigerant level. Adding to a system that's already full is a recipe for disaster. Figure out why the thing is cycling, fix that, and then recharge.

If you are in fact low on refrigerant after only a month, take the car back to the shop that did the work so they can fix the leaks, evacuate and recharge.

dr bob

Oh, and the picture shows "jumper wire for compressor" pointing to the pressure sensor for the fans/flaps. The safety switch for low pressure is directly below that, facing up into its connection on the liquid piping.

inactiveuser1

I did find the under the hood link that help show some.
http://members.rennlist.com/v1uhoh/underthe.htm
I see the link now 19 is for the pressure fans where I marked 1&2
#15 on the link showed high side glad I waited on hooking anything up!It was serviced at a Porsche dealer that did the work so will take the advise to bring it back in,will have to call Monday its only been a month and 150 miles!
Thanks,
Mark

inactiveuser1

I took another picture of the blue removeable cap right next to the coil on the passenger side.I take that this is the low side for the AC that you are talking of.You can the jumpstart terminal and the air intake hose.If so maybe we can get Tony to ad to his page of under the hood.That page is excellent!
I took the picture to get a clear shot of it,if he can use it.
This is from 1987 928 S4
Thanks,
Mark

inactiveuser1

I turned air on again front and rear while the car was cooled down and now the air compressor sounds ok.Will take it out tomorrow or Sunday for a longer ride when it warms all the way up to temp and see if the AC clutch makes noise again.One thing for sure with the slider all the way to the left on 65 the air is super cold.Will let you guys know what it does.
Thanks,
Mark

dprantl

If the air blows cold, the compressor kicks in and out many times a minute and when it kicks in it seems like a large load on the engine, the system may have been overcharged. You should hook up a gauge set to the low and high sides and get some pressure readings.

Dan
'91 928GT S/C

dr bob

???? There's no high pressure switch on his car, so a more likely cause is the anti-freeze swich doing its job, or a compressor relay in the head failing. Or the plug loose on the back of the AC switch in the console.

inactiveuser1

Went out today for about 2hrs did some testing with air on and air off.When the car is cold 1st start up the compressor is quiet NO clicking in and out.Then I watched the water temp gauge.It is ok till the 1st white line which is about 1/3 way up.Once the thickness of the red needle is over that area it seems ok also.Then when it gets just alittle higher temp the clicking in and out noise starts from the compressor area.The car never gets over 1/2way on the gauge when you turn the air off.If I turn the air back on when 1/2 way on the temp gauge the clicking is there also.
Let the car cool down again below the 1st white line area which is about 1/3 way up on the gauge and it ok again.
Whats best to try then?
I would take it back to the dealer but if its the anitfreeze switch and I can try myself would do that to see if I need to take it back it.
Of course would need to know locations so I can take a look.
Any ideas on what to try 1st?
What part of the console back by the rear air?
1987 S4 with AT
It does blow cold air thats for sure.
Thanks,
Mark

Charley B

Are you sure you're not hearing your cooling fans cycling? The relationship to your temp. gage is suggestive.

inactiveuser1

When I had the hood open listening it seemed to be coming from the lower passenger side.Soon as the AC switched is pushed in the noise starts soon as you turn it off it stops.Kind of like Dan mentioned many times a minute.Tomrrow will look again to see if the fans are kicking in and out but still sounds like lower passenger area.There is a heavy load on the motor when doing it you can see the tach drop off maybe a 200-300 rpm.
Thanks,
Mark

Charley B

Well the engine load sounds like A/C but the dependance on temp. and A/C switch sound like fan issue's.
Perhaps you're dealing with both, but not differentiating between sounds, as each is activating.