Join Date: Jun 2013
Location: West Grove, PA
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But then why did GM not change the specification for my Impala until a few years after it came out? The original PF63 oil filter was specified for my 2012 for a few years before they changed the specification (the original PF63 had the lower bypass valve spec). Surely, they would have realized that the spec needed change right away if they changed the internal clearances? Did it really take them a few years to realize this?
And why do they still recommend the lower bypass valve spec for the police Impalas (same engine, slightly modified tune)?
Something just doesn't add up here...
And please don't get me wrong - I'm not trying to shoot the messenger here. I've seen that article that you linked to before, but that is the ONLY place I've read such a thing and not sure what to believe. To me, if they changed the internal clearances enough to warranty an oil pressure change, you'd think that they would also adjust the oil filter specs to match - instead of waiting a few years - and even then, not changing it for police vehicle oil filters, which are driven harder and longer than normal vehicles.
They also state "starting in 2012" - so does that mean that some LFX engines are differernt than others? Or are they saying that 2012 is when the LFX engine was first being produced? Obviously, if some LFX engines have higher tolerances than others, that could really be confusing! :-) I also wonder why the TSB mentioned above only covers 2012 and 2013 Impalas, even though the TSB is dated 2017 - what about the 2014+ Impalas - they don't need the revied oil filter? :-) It just doesn't make sense to me.
Like I said above, I'm certainly not an expert on the subject, so these are genuine questions. Either GM really dropped the ball (by not adjusting the oil filter specs originally *and* not updating the specs for police vehicles) or someone is making this crap up.
I also wonder if the oil filter spec difference *really* makes a difference on properly maintained cars...
Last edited by jtrosky; 09-22-2018 at 08:28 AM.