Checking The Antifreeze Content Of The Coolant Using A Refractometer

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Information

Leitenberger display scale . > T10007A - Refractometer
Leitenberger display scale . > T10007B - Refractometer
The scale can vary slightly, depending on the manufacturer.
The ETHYLENE scale must be used for Porsche antifreeze.
Other commercially available testers can also be used provided correct results are guaranteed.

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Refractometer

Item	Designation of the display	Explanation
-A-	Scale for propylene-based coolant	Do not use for engine type M48.
-B-	Scale for ethylene-based coolant	Coolant such as elf GLACELF SUPRA. Use for engine type M48.
-C-	Scale for battery acid	The charge state of a battery can be checked here. The values on the left side indicate the specific gravity of the electrolyte. The battery must be recharged once the charge drops below 1.20.
-D-	Scale for alcohol-based windscreen cleaner	The freezing point of the windscreen cleaner can be read off here.
-E-	Light/dark limit	In conjunction with the points of intersection of the relevant scales, it specifies the value to be established.
-F-	Waterline	The light/dark limit must be located here when sprinkled with distilled water.

Using a pipette, take a sample from the coolant reservoir.

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Pipette
Deposit a few drops on the test surface.

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Depositing drops on the test surface
Close the light-diffusing lens. A closed film must form.

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Closing the light-diffusing lens
Using the refractometer, view against a very bright light source. A very clear light/dark limit emerges. The point of intersection between this line and the display scale marks the freezing point of the coolant.
A freezing point that is too low must be adjusted accordingly.
Information
- The following table specifies how much coolant must be replaced by pure antifreeze in order to adjust the freezing point to -37°C.

Measured antifreeze protection in°C	Antifreeze quantity to be added (in litres)
- 5	9
- 10	8.5
- 15	7.5
- 20	7
- 25	5

Measured antifreeze protection in°C	Antifreeze quantity to be added (in litres)
- 30	3.5
- 35	1.5