M201 - Anti-freeze / Anti-gel markings
The M201 above was sold at auction with a very low mileage on the clock having never been rebuilt. It had been held in reserve for probably its entire life. The markings stencilled onto the windscreen clearly indicate that this M201 was suitable for very cold climate use. The information can be decoded as follows: AG - antigel (antifreeze) XS 791- product code (protection to -35C) Permanent - (the protection is permanent). Thanks to JLM for decoding this for me. Another product was also used by the army XS 691 offering protection to -25C.
The second photo is also of an M201 that had been kept in long term storage (remnants of the typical red wax used to seal components from the damp can be seen round the regulator box connections). In this example the anti-gel record was stencilled under the bonnet. Closer inspection reveals that, in this case, the winter (1980/81) rather than grade of anti-freeze was recorded.
It is difficult to say whether this indicates when the jeep was last in service or when it was put into storage but at a guess storage seems more likely. Thanks to Jan Koncicy (M201 no. 04494) for the two photos above.
The photo below (from the book 'Sur les traces de la légend Jeep' by David Dalet and Christophe Bitoux) is the only clear evidence I have seen of anti-gel markings on a jeep in service.
The ANT 57 (anti-gel 1957) above the grille seems a little bizarre given the palm tree / desert setting but it certainly snowed in the mountains of Algeria during winter. The jeep is not an M201 but of WW2 origin, probably an ITM jeep (note the wood blocks on the bonnet).
Antigel specification was sometimes part of a more complete list of fluids and lubricants that were sometimes stencilled under the bonnet of jeeps in storage.
Thanks to Ken Chapman for sending this photo. Information about the other products specified can be found here.