Lotus Elan Central
Changing Your Engine Coolant

This procedure runs through changing the engine coolant in your Elan. It is recommended the coolant be changed every two years (minimum). The original factory coolant is a 40% concentration of "Shellsafe Plus". The service notes recommend a 40% antifreeze/water ratio. In cold climates the maximum concentration recommended is 60%, while in hot climates the minimum concentration is 25%. The total system refill capacity is about 5.2 US quarts (or 5 litres for you right-hookers).

Do not change the coolant unless the engine is cold!

Difficulty level = 1 out of 5     —     Cost = about $10

What's Needed:

  • Distilled Water (a few gallons)
  • Antifreeze (minimun 2.5 liters)
  • Red Line WaterWetter (optional -- see notes below)
  • Coolant system flush agent (optional)

Draining The Old Coolant

  1. Let the engine cool.
  2. Turn the heater dial to the hot end (for the entire procedure).
  3. Remove the coolant reservoir cap.
  4. Now remove the drain plug from the bottom left hand corner of the radiator (on U.S. cars) or disconnect the bottom radiator hose (for all cars). You can just reach under the front bumper to remove this drain plug!! (Note: This is a plastic screw-bolt which is meant to be hand-turned only! It is slotted so it is not necessary to remove the bolt completely--although you can if you want. One owner had this drain plug break accidentally--so be careful with it!)
  5. Dispose of the old coolant properly (look at the old coolant color and contamination and be happy you are changing it)!

Adding New Coolant:

  1. First carefully replace the drain plug or radiator bottom hose.
  2. Fill the coolant reservoir with distilled water only, until up to the cold level indicator mark. (this refill is done to rinse the remaining old coolant from the engine that was trapped within) You may add Coolant Flush agent to this part of the procedure.
  3. On non-U.S. cars, this slow refill process may be expedited by removing the bleed plug in the left hand headlamp well to bleed air from the system, and replacing it when a steady stream flows out from it.
  4. Keep track of how much it takes to fill so you will know how much you are about to use when you add the final coolant.
  5. Now run the engine (with the water-only in the system) with the reservoir cap off and top up the coolant reservoir until the level stabilizes or starts to rise.
  6. Run the car long enough to get it to normal operating temperature. This will assure the Thermostat opens and the coolant circulates out of the engine and the flush goes through the engine!!
  7. Stop the engine and allow it to cool again.
  8. Now drain this "water flush" out. (Steps 2-6 can be repeated if you wish)
  9. With the rinse done, you may now add the final coolant mixture.


To keep deposits from forming inside the engine coolant passages, I recommend using ONLY "distilled" water to mix with the antifreeze. Since last year, on a recommendation by Seamus, I've added Red Line WaterWetter to the coolant. Yes, I am amazed with the improvement since then. My car used to run at the lowest tick on the gauge at normal temperatures--now it runs at the very bottom of the gauge. Even better, it takes nearly forever for the temperature to come up to the 3/4 mark, where the accessory cooling fan kicks in, when sitting in traffic

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