From 1971 through 1973, Imperial utilized an ingenious automatic climate control system called AutoTemp II. Unlike mere air-conditioning, AutoTemp II maintains any interior temperature the driver desires regardless of exterior conditions. Set at 72 degrees, AutoTemp II holds the cabin temperature at 72 degrees whether battling desert heat or winter's chill.

Once the system is turned on with a push of a button and the temperature set with a turn of the dial, hardly any further adjustment by the driver is needed. AutoTemp II controls the fan speed, air temperature and where air is delivered.

A genuine aid to driving comfort and impressively discrete in operation, AutoTemp II is a desirable accessory for any Imperial or Chrysler Product. Unfortunately, for all its wonder, AutoTemp II is flawed. The plastic body of the AutoTemp II servo, which resides under the hood and controls water flow, fan speed and air door operation, cracks with age - especially under conditions of high heat and pressure.

When cracking occurs, the results can be as severe and dramatic as massive coolant loss, or as perplexing and menacing as coolant seeping internally into the servo's electronic and vacuum mechanisms. The result in both instances is complete loss of climate control.

What to do when this happens to your AutoTemp II?

Brave AutoTemp II owners can attempt to repair the servo's plastic body using glues and resins, but such repairs invariably fail, and new cracks develop elsewhere in the body. New servos are no longer available through Chrysler Corporation. Used servos, even in fine condition, will eventually fail. Fortunately, there is a permanent solution to the AutoTemp II servo problem. The Auto Temp II servo has been reproduced with a durable aluminum body.

As it happens, Mercedes-Benz used the Imperial AutoTemp II system from 1976 through 1981. Mercedes-Benz owners, like their Imperial counterparts, experienced servo failure. Seeing that the plastic body was the problem, one Mercedes enthusiast made a new body from aluminum and found a source for the internal mechanisms. He now sells these improved servos to delighted Imperial and Mercedes owners.

The aluminum-bodied servo is an exact replacement for the Imperial original (see pictures at right), and even has the cold engine lockout switch fitted to the bottom. One of these aluminum servos is installed in my 1973 Imperial, and has solved my AutoTemp II problems. The new servo is leak-free.

This excellent replacement part is available from Performance Analysis Company, 1345 Oak Ridge Turnpike, Oak Ridge Tennessee 37830. Phone is (865) 482-9175. (Special thanks to Gary Thomas for discovering the new area code for Performance Analysis.)

The aluminum-bodied AutoTemp II servo is available in two price levels. The higher, which I purchased, costs $495 and features all-new internals. The lower costs $395 and uses remanufactured internals, but has the same aluminum body and all new gaskets and seals.

Frequently Asked AutoTemp II Questions

1. The air-conditioning compressor of my AutoTemp II equipped Imperial runs all the time. Is this normal?

   Yes. AutoTemp II runs the compressor continuously. This allows AutoTemp II to dehumidify and filter the air, as well making it possible for AutoTemp II to mix cold and hot air for the perfect interior temperature. However, when the ambient temperature is below 32 degrees, the compressor, by design, does not operate.

2. When I first turn on my Imperial and the AutoTemp II is switched to "on", the fan doesn't come on immediately. What's wrong?

   Nothing. In order to prevent the driver and passengers from being chilled by a blast of cold air, AutoTemp II waits until the engine coolant temperature has reached 125 degrees before turning on the fan.

3. Why does the cabin become hotter and hotter when AutoTemp II is set to "Hi-Def"? My AutoTemp II works well otherwise.

   "Hi-Def", or high defrost, is intended for severe winter conditions when extra glass clearing is needed. It overrides AutoTemp II's thermostat setting, providing the hottest air possible as well as the highest fan speed. For a more gentle defrost, select "Def".

4. Under hard acceleration, the AutoTemp II fan quits. Once the car is cruising again, the fan returns. What's wrong?

   There is either a vacuum leak in the system or one of the check valves under the dashboard on the passenger side has failed.

5. Even after I turn off the car, I can hear AutoTemp II working. What's happening?

   AutoTemp II is simply parking the system. Please don't tip the AutoTemp elf living in your dashboard.

6. How can I maintain my AutoTemp II system?

   Use it! Approximately every two weeks, run your AutoTemp system for a few minutes on high defrost. This will help keep the valve in the AutoTemp II servo lubricated. Also, keep your engine coolant clean. Do not use ANY stop-leak substances as these can clog the servo (have your radiator repaired properly). When flushing your coolant system, remove the AutoTemp II servo so as not to clog it with any rust or debris flushing will agitate.

   If you are stuck with a plastic-bodied servo - make sure your cooling system is in top shape. Have your hoses checked and radiator cleaned. Make sure your coolant level is correct and the that your coolant is in the right proportions. Over-heating episodes severely reduce the plastic-bodied servo's life-span. Before taking any long trips, check the servo for leakage. A small leak in the driveway will surely develop into a large gusher on the freeway.*

   *All repair or maintenance work performed is at the reader's risk. The author assumes no liability for damage that may result from advice taken from this Web site.