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A2 cooling sytem/AC

89 Jetta 1.8 SOHC automatic. The vehicle is not overheating, but as the water temp begins to climb past halfway on the gauge, the AC cuts out.

Basically, under normal driving conditions the water temp needle sits a hair to the left of center. If I sit in a drive thru line, or sit at a light too long, the water temp goes up. As it gets just a hair past halfway the AC hisses and blows warm. As soon as I get going and the water circulating, cold AC comes right back.

I'm assuming this is normal, but not sure. I personally think it cuts out too early, and should cut out as the needle gets closer to 3/4 hot.

FWIW new radiator, thermostat, rad fan switch, rad cap, and coolant.

Thoughts? Paul

Reply to
Simplstupd
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Looking through the various circuit diagrams, it seems VW changed the A/C and radiator fan wiring on a weekly basis. Basically, the radiator fan is supposed to come on at low speed whenever the A/C is turned on (regardless of whether the compressor clutch is actually engaged or not) or the coolant temperature gets moderately hot. The radiator fan is supposed to come on at high speed if the coolant temperature gets very hot or if the A/C refrigerant pressure gets too high. I believe on the '89 Jetta the radiator fan high speed mode was controlled by a single relay where the coil side was connected to both the radiator thermo switch and the refrigerant high pressure switch. If this relay were to fail, you might get the symptoms you describe.

Do you ever hear the rad fan high speed kicking in?

I have not actually had this relay >

Reply to
Randolph

You oughta have an '89 jetta, then. ;/) Mine even beats the heat of the texas summer - no mean feat. R12 is certainly getting harder to find tho.

As to Simpl's problem, it also sounds like a relay problem to me, too, and it would be worth swapping out the old one for a test. But it also seems to me that there's a cutoff switch when the system pressure gets too high or too low or something. How long has it been since your AC system had a tune-up?

Chris

Rob Guenther wrote:

Reply to
starburst

Guess what the problem was?

The radiator fan was not coming on due to a bad connection. Cleaned and secured the connection to the rad fan and all is well.

Reply to
Simplstupd

Reply to
Rob Guenther

Cool! (yuk yuk) Thanks fer posting the update - Chris

Reply to
starburst

Rob, are you going to fix your date issue? You're still posting a day into the future...

Reply to
Biz

Reply to
Rob Guenther

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