2004 Porsche 911 40th AE (996) 86k mi; Driven DT40 5w40, 500 miles on oil

[sds911]

Just received this DT40 UOA from Cat Labs tonight. Low mile run, but in sump from 8/2023 to 8/2024. Driven DT40 5w40 8 qts. Topped with 1/2 qt of Castrol Edge 5w40 Euro.

Prior two fills also used Driven DT40 5w40. Last 2 columns of Blackstone report below. Note these short mile changes indicate lower zddp possibly due to DT40 competing with prior oils used in the earlier changes (such as Liqui Moly Leichtlauf Hi Tech 5w40 at 83,388 change and 82,267).

FlatSix/Raby has advised that DT40 doesn’t play well with some other blends (like M1 0w40) and it could take two fills or a short run of Driven 30wt to get all old oil out of engine before seeing true impact of DT40.

 

[sds911]

Between 58k and 82k oil changes in BS Report above, I had multiple additional oil changes using Castrol 0w40, 5w40, Motul 5w40 Excess (all A40 approved) and DT40 when my IMS Solution installed around 73k. I may also have used PP or PUP 0w40 or 5w40 earlier b/c I remember buying the quart bottles. I may not have done UOAs on some or all of those earlier changes.

Current fill is Mobil 1 FS 5w50, and have DT40 ready in garage for next change. I really like the DT40, but will only buy on sale. Going to use my last sale purchase of DT40 soon, since spring weather is here and I want to run UOA on the Mobil 5w50 - which was bargain price of $60 at napa for 9 or 10qts.

 

[fantastic]

Your Porsche is getting low mileage changes and just sticking with annual?

 

[sds911]

Your Porsche is getting low mileage changes and just sticking with annual?

I rarely drive the Porsche right now. Short oil changes for various reasons over past few years - including potential fuel dilution, lifter noise vs dreaded bore scoring, a couple high SI readings compared to 2013 UOAs.

Several projects I need to do on it too, but haven’t been inspired yet. Anyone in Colorado want to help with them lmk. Beer and food on me. The car drives well and sounds good at the moment.

I’m pleased with the most recent UOA by Cat and think I have another DT40 sample from when I put in the Mobil 1 5w50 fs. I had one sample bottle filled with no labeling and wasn’t sure what it was when at Cat dealer. I usually mark sample cap with info and black sharpie. But, I’m pretty sure now it must be the most recent DT40 run. I’ll drop it off to CAT and see what comes back. If it is DT40 the numbers will be consistent. I’m pretty sure that run had more miles in excess of 1000.

But, my GX 460 is my daily driver and more comfortable with passengers and for my dog(s). I did get pulled over once in Utah for speeding and had my 3 dogs in the 911. Thank goodness the 911 has back seats.

Need to join the PCA again here in Colorado and take it out now that winter is over. I usually take it out for a drive every few weeks to get everything moving, get oil up to operating temps and gun it WOT during drive after reaching operating temp (as advised by Tony Callas at Callas Rennsport whose shop installed my IMS Solution and he assisted with a few other issues along with FlatSix/Jake Raby and Lake Speed Jr. on UOAs.