[s-cars] Castrol GTX High Mileage Oil - the real issue is not "seals"

[Taka Mizutani]

Scott- is Castrol GTX HM formulated for higher ZDDP? The current S* spec
oil mandates lower ZDDP levels, so you won't find a conforming oil with
high ZDDP levels.

I'm glad that you find it so important to comment every time I put anything
on the list.


On Tue, Dec 17, 2013 at 1:11 AM, Scott Justusson <qshipq at aol.com> wrote:

> Sigh, here we go again....  This has nothing to do with seals, swelling or
> (OMG) the switch from synthetic to dino oil.  This is an educated mechanic
> legitimate concern about M1 products reducing the levels of Zinc and
> Phosporus to comply with the lower EGR/catalyst effects of wear additives,
> driven by the EPA>Car Manufacturers.  One might argue that, esp on cold
> start, an engine at 245k would benefit from extra ZDDP(dino)/ZDTP(synth)
> Zinc and Phosphorus.  Previous levels were in the 1100-1300 range, the new
> standard is sub 800.  M1 Claims this change is safe for new and 'old'
> vehicles, but I think that is plain marketing BS.
>
> The best compromise to the OP IMO, is to switch to M1 Turbo Diesel Truck
> Oil or a Delvac Synthetic, as both retain much higher levels of cold
> start/worn engine tolerance, wear barriers.  Short of that, a change to a
> Castrol dino product will yield the same results.
>
> As a rule I don't enjoy engine oil discussions, but dragged in by a
> point-by, happy to back up the educated mechanic recommendation and
> concern, than anyone focused on 'swelling seals' totally missing the
> legitimate issue.
>
> BTW those in select states might just find that M1 Turbo Diesel Truck oil
> by the gallon at Autozone, is less than Wallyworld brand dino oil.
>  BtstockeduponT
>
> Taka, you just try to hard, it's the Holidays, and it would appear Mr
> Rodrigez educated mechanic is just looking out for a good customer.
>
> Cheers
>
> S "Taka point-by again" J
> 95.5 S6 M1 Turbo Diesel Truck OIl
>
>
>
>
> -----Original Message-----
> From: Taka Mizutani <t44tqtro at gmail.com>
> To: s-car-list <s-car-list at audifans.com>
> Sent: Mon, Dec 16, 2013 2:50 pm
> Subject: Re: [s-cars] Castrol GTX High Mileage Oil
>
>
> I would not do that myself- going from full synthetic to a conventional oil
> with seal swellers doesn't really make sense to me, especially if
> you've had no issues with running synthetic. The synthetic will last longer
> and be more resistant to viscosity breakdown, often has a lower
> pour point and a higher flash point.
>
> However, you should ask Scott because I am not qualified to answer any
> questions about cars at all.
>
>
> On Mon, Dec 16, 2013 at 2:56 PM, Thomas Rodriguez <trodri69 at gmail.com
> >wrote:
>
> > My '95 S6 has 245K miles.  Head was rebuilt about 40K miles ago but
> > otherwise the engine is original. I've been using Mobil 1 5W/30 synthetic
> > motor oil for as long as I can remember. Engine runs strong. I add about
> a
> > quart between scheduled oil and filter changes every 3K miles.  Otherwise
> > there are no signs of burning or leaking oil.
> >
> > Last week my mechanic recommended we switch to Castrol GTX High Mileage
> > 5W/30. I agreed and have driven about 300 miles with this oil in the
> > engine.  I understand that this oil is not synthetic.
> >
> > Any thoughts about using the Castrol GTX HM oil?
> >
> > Tom
> > '95 S6
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