The above two uoa results from CAT with pennzoil longlife and now mobil delvac keep suggesting an overheat situation.
Vehicle is 4.2 TD Toyota landcruiser, no intercooler.
The engine runs cool according to the gauge on the dash - barely above the blue cold mark.
Consistently - the results are oxidised oil - even with the best synthetic and a lower distance travelled (4000 miles).
Wear levels are higher in Fe & Al slightly on the delvacthan the pennzoil.
Would an after market oil cooler perhaps benefit this engine? Maybe the heat of a non intercooled turbo is whats oxidising the oil?
I'm thinking an oil cooler might be cheaper initially than a intercooler?
The only modification to this engine is an LPG injection system that runs in paralell with the diesel.
Could the LPG be the cause of higher oxidation levels?
(I read something once about LPG powered forklifts needing oil with a higher sulphated ash content to prevent valve seat regression).
Does LPG cause higher oil oxidation levels?
Just trying to figure a fix for this oil issue - on an engine that otherwise never misses a beat.
Many thanks in advance.