From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Guidance on vehicle overheating, radiator shutters, and the function of the red warning light.
| Identifier | ExFiles\Box 24\5\ Scan308 | |
| Date | 1st August 1930 | |
| -4- Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}1/W.1.8.30.Contd. with a louvred bonnet should be free from over-heating up to an atmospheric temperature of 30°C. and if trouble occurs at a temperature below this the car is not up to standard. Incidentally, owners should be told that the red warning light is a device provided to prevent them forgetting to open their radiator shutters and not an indication that the car is overheating badly and cannot be driven further. Actually, the car can be driven all day with the red lamp on and the thermometer showing 98°C. - 99°C. and yet only lose 5 or 7 pints of water which causes no harm whatever. Hs{Lord Ernest Hives - Chair}/rm.{William Robotham - Chief Engineer} | ||