deliriousga

Is the low side connector in front of the radiator on the right (passenger) side? The connector is on the side of a canister with two wire connectors on top. I want to make sure before I test and fill and I can't find it listed in the manuals anywhere.

TIA!

m21sniper

There should be fittings to plug into without having to remove your pressure sensors(which is what that thingy with the two wires is).

JimBob951

I wish it was! That would make things ALOT easier. Unfortunatly, the low side connector is on the other side of the radiator, under the rad hose. It's very difficult to get to without getting burned! I let the car cools first before I test/fill.

Jim
87 928 S4 a/t
87 951

Atlas_Croc

The high side is the one near the pressure sensor / drier. The low side is tucked under the upper radiator hose just to the right and below the passengers side ignition coil.

deliriousga

Thanks for the info everyone.

rixter

John,
the low side is a PITA to get to... to fill the system properly it must be running
make sure you have CLEARANCE on your gauges/hoses PRIOR to starting the car
and whatever you do DON"T stick your hands down there while it's running... hands and fans don't mix

Alan

All,
It does vary by year. On the GTS its in the bulkhead area, under the cover next to the windshield wiper motor - its a pain to have to remove (and particularly to reinstall the cover) - but no fans to worry about and relatively easy to reach.

Alan

Steve J.

When in doubt, the larger line is always the low pressure line and the smaller diameter line is high pressure.

Ed Scherer

Bringing it to life with photos...

This is where stuff is on my '90 S4:

Low side:



zoomed in a bit more:



High side:



You got that right, Jim. It took about an hour of this (blower on high) ...



... before I could get in there to detach the low side hose after charging my AC system about a month ago.

borland

Been there, done that. A better solution for the S4 low side is to buy one of these "PRO-SET" adapters..

with a cutoff valve, specify blue valve handle:

http://cgi.ebay.com/ebaymotors/Ball-...6266QQtcZphoto

Or this adapter:

http://cgi.ebay.com/ebaymotors/1-4-S...5847QQtcZphoto

The PRO-SET adapters are very low profile, so they fit nicely.

This is for the factory R12 fittings only. If your car has been converted to R134 the converted fittings may be even more of a interference problem.

If you look at this ebay seller's store, you'll find he has just about everything you could possibly need.

borland
S4, Slate Metallic

borland

Also, with the adapter, you stand less of a chance of damaging the car's connection threads (aluminum).

This (damaged threads) can happen when your trying to thread the hose to the fitting and are struggling with a water hose interference (cross thread damage), or when removing the gage set hose from the car's fitting while under pressure.

Also, using an isolation valve on the high side, eliminates blowing oil when disconnecting the high side hose.

Pfunde

Totally agree with borland, adapter's - my a/c guy made adapter's for my cars - take less than 15 min for a refill now.....

marinesniper0318

So just a quick question, when adding more freon you add it to the LOW side correct...?

dprantl

Yes, with the engine running and the compressor on. Make sure you purge the line from air before opening the can.

There is also a way to charge liquid directly into the high side with the engine OFF. Never ever try to charge from the high side with the engine and compressor running.

Dan
'91 928GT S/C 475hp/460lb.ft

blown 87

Correct, low side only, cans have been known to explode when hooked to the high side, always wear safety glasses at the very least.