John,

 

As far as the A/C goes, it likely won't matter which fan you have, since the low speed will likely be comparable between fans.  If you get above the high temp setpoint on the radiator temp switch, it cuts the A/C to cool the engine (the condenser is basically a pre-heater for the air feeding the radiator when the A/C is running).  Sounds like you have a cooling (engine) issue more than an A/C issue, per se.  All the compressor "knows" is that the radiator temp is too high, it doesn't know anything about ambient temps.  Also, when you're going 55mph, the fan is totally irrelevant, as the amount of air going through the radiator due to speed is much greater than anything the fan can do.  Around town, yes that fan would help, but the A/C will still cycle off when the high speed kicks in (unless you wire it differently than stock.  Might be time for a radiator replacement.

 

One other thing to consider relative to the high low-side pressure - if the compressor is cycling on/off due to heating issues, then you may never get the suction side pressure down to where it should be.  But if you do get some high/low gauge readings, post them and we'll see what we can figure out.

 

Keith Hughes

'86 Westy Tiico (Marvin)
 

Date: Tue, 22 Jun 2010 13:13:09 -0400
Subject: Re: A/C Shuts Off over 55mph
From: jvantslot@gmail.com
To: keithahughes@q.com
CC: vanagon@gerry.vanagon.com

Keith,

Thanks for the explanation. I will work on getting the gauges and get an accurate pressure reading.

I have a 1987 Vanagon GL parts car.  One option is to put the more powerful fan from it onto my 1984 Camper.  Do you think I would see a performance improvement? ie, A/C shuts off above 55 mph at the same ambient temperature? 

Anyone tried this? I am wondering how many parts from the newer system would need to come over from the '87 to my '84.

Thanks,

John