Quote:
Originally Posted by Gilles
JFP, the same applies to the 9A1 engines (on the 981's..?)
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The direct injection systems on the 9A1 engines add a complication that rear's its ugly head as bore scoring. DI engines suffer from cylinder wall "wash" during start up and cold running; as such they need an even better oil designed to deal with this phenomenon, like the Joe Gibbs Driven DI 40, which carries additional moly along with the ZDDP. 5 K miles would also be the absolute limit on these engines.
Changing the thermostat on some of the 9A1 engines is also somewhat more complicated and many used a complicated "thermal control unit". Fortunately, LN has produced a 160 F unit specifically for these cars from 2009 to 2012. Later cars use an completely electronically controlled system for which there currently is no replacement.