Other than the engine, I think they should be more reliable. I'm not saying the engine is more or less, I don't know. The 120 looks very like the 90 underneath. Hopefully the changes relate to stuff that didnt last on the 90. I can see the trailing arm bushes are bigger on a 120, and the rear shock mounts dont have the mud trap that makes them rot on a 90. The 120 is much nicer to drive on the road, I think. Smoother and quieter. Not much in it offroad.
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I would say the 120 is better overall, it has to be, it is a whole new body on a similar updated chassis.
We should only compare the older 90 series having the D4-d engine, (not the tractor 1KZ) to the 120 series.
The 120 is more comfortable inside, and rides more comfortable also.
More powerful, and dare I say, quicker accelarating, with a higher top speed, also more economical, with the auto being more economical than the manual for a surprising change.
Definatly more quieter inside, internally more ergonomic, externally more rounded curves, to reduce wind noise
The "head cracking" I believe was only associated with the older 1KZ engine, with the autos being much more prone to it than the manuals.
I haven't heard of a 120 series, manual or automatic, giving any cooling problems, more lessons learnt by Toyota I guess.
Saying that, they did go through a bad patch with the injector seals, but I guess these have all been rectified now, by way of recall, or done via service interval.
Gra.