AC UPDATE/NEW FAN

L31MaxExpress said:

When I last charged the 97 van it was over 100F but it was right after sun down. Just too darn hot at the time to mess with it during the day. I have not had to put gauges on it since las summer. I am so familiar with duster gas pressures now the exact R134a pressures throw me occasionally. R134a definitely runs a lot higher, but I seem to remember seeing no more than about 350 psi on all the R134a dual evaporator systems I have worked with even in 100F in the sun.

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JohnZ71 said:

Yeah the 350+ pressures for me happen only in direct sun and sitting a while. Ton of heat builds up in the engine bay. For example sitting there today, my mirror said 118 degrees and that’s coming from in front of the condenser.

Last year or so, I forget when now…the engine would start running hot at idle, it would get up to 230 after about 15-20 minutes. I replaced the entire AC system at that time including the condenser and it stopped running hot at idle after that.

It still has a ton of engine bay heat that contributes to the high head pressure I believe but it’s not running hot. It idled all day without getting over 190, very impressive.

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L31MaxExpress said:

Does your accumulator have the insulating blanket? Is the foam insulation still on the metal and rubber suction lines? Any place the system can pull heat into the lowside hoses in the engine bay can add to the heat load thus pressure.

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JohnZ71 said:

The foam is still on the accumulator, but it’s very loose and I don’t see it doing much. The low side AC line is exposed, I was under the impression insulating them doesn’t matter because they’re in line After going through the evaporator. Is this incorrect?

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L31MaxExpress said:

Incorrect keep all the heat you can out of the system.

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JohnZ71 said:

Insulated the accumulator and low side lines. I removed the air intake box and duct to get to it all easier and I forgot to wrap up the rear lines, I assume they’re cold as well? They are on the fender well and have very little foam left. I’ll wrap those when it cools down maybe this evening.

While wrapping the accumulator, I noticed a broken vacuum line that goes between a switch on the firewall and the heater control valve on the fender. With this broken, would that allow hot coolant to constantly flow through the heater core?

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L31MaxExpress said:

The rear suction line will be cold all the way to the rear evaporator core. On my Express van there is a section of suction hose that runs over the exhaust, next to the transmission, behind the engine and over the top of the engine. Insulating that 6' section with more insulation made a noticeable difference on its own. That section had some plastic split loom covering it to start with.

The heater valve closes with vacuum. Vacuum solenoid opens with the recirculation mode active. The recirculation mode can activate either by pushing the button or automatically from the recirculation pressure switch closing when the refrigerant head pressure hits ~275 psi from memory.

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