On Apr 15, 2:35*pm, Lon > wrote:
> On 4/13/2012 22:37, Budd Cochran wrote:
>
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>
>
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> > > *wrote in message
> ...
> > On Apr 10, 9:56 pm, "Budd > *wrote:
> >> > *wrote in message
>
> ....
>
> >>> Need some advice about my 2001 Grand Cherokee limited with 83,000
> >>> miles on it.
>
> >>> I purchased it new, it was demo and took very good care of it changing
> >>> oil ever 3000 miles. Also kept up the maintenance according to the
> >>> manual.
>
> >>> The place (not the dealer!) where I get the fluids changed recommended
> >>> that I consider changing to synthetic oil . I was told there is a
> >>> special oil for engines over 75,000 miles.
>
> >>> Anyone have any advice/experience about using or changing to synthetic
> >>> oil?
>
> >>> I am also wondering about how long the 4.7l engine is generally good
> >>> for. In the past in this group I have heard that GCs tend to start
> >>> needing expensive work soon after 100,000 miles.
>
> >>> Any experiences with long engine life?
>
> >>> Thanks in advance.
>
> >>> Larry
>
> >> Most of the "special" oils for high mileage engines are aimed at
> >> non-roller
> >> lifter engines (solid lifter or old style hydraulic lifters) and contain
> >> zinc additives to lube the cam and lifter contact points ... actually,
> >> they're just old timey oils with a higher pice tag.
>
> >> I don't know much on the 4.7, but if it's a roller lifter engine there's
> >> no
> >> need for the zinc additive.
>
> >> As for longevity, keep it tuned, lubed, cleaned and don't abuse it and
> >> it'll
> >> last longer ... simple as that.
>
> >> Budd
>
> > Thanks for that advice...
>
> > I googled Jeep GC reliability and came across what appears to be two
> > persistent problems....front rotors and something about blend door
> > failure that plague the limited. * The front rotor problem I
> > experienced just after the warranty expired. *Not sure but I might be
> > dealing with that issue again.
>
> Front rotors on some models sensitive to ham fisted poor torqueing of
> wheel nuts. * Can be avoided by using a torque wrench.
>
>
>
> > But the blend door issue, having to do with the heating system vents,
> > was new to me.
>
> The auto temp control system can be a real pain, and if it ever truly
> goes bad and you cannot fix it yourself, quite expensive.
>
> Best investment is the Factory Service Manual, which you can buy online
> at jeep under the for owners link.
>
> There are special high mileage oils, but 75-80 isn't that high.
>
> Pure synth, or synth blend is pretty much a personal taste unless the
> owners manual calls out synth due to engine design.

I appreciate that reference to the Factory Service Manual. I think I
will be keeping the GC rather than trade and the manual sounds like a
good investment! If the blend door problem shows up, I will just deal
with it.

Still thinking about the move to synthetic oil.

Thanks for the advice!

Larry