Oil Change Interval with Delvac

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Aug 17, 2003
Boise, ID
Okay so I want to start using the new Mobil 1 Truck/SUV formula --errr Delvac --shhhh -- in my SUV (well out of warranty). I would like to use the oil mainly for longer oil changes and good protection it offers. I have read on the boards how this is a super high mileage oil used in trucks. I drive about 15k miles a year of mixed highway and city driving. With filter changes every 5k miles or so, can I run the oil for 1 year without worrying about TBN or contaminates getting to high?
I'd run it for 7500 miles/6 months and then test it - prior to doing the first filter change - to see how much margin of safety you have left. Post the results on this board and you'll get some good advice. It should be fine for at least 10k miles, but a lot depends on how efficiently the engine is running and the # of fuel related contamination you get. What engine is in your SUV?
Yeah I was thinking about doing the UOA half way through the year. I am running an older pathfinder with the good old 3.0 V6
In that case, I'd do the first filter change after 3000 miles and be alert for signs of oil consumption after a few thousand miles. Delvac 1 will clean out all kinds of oil deposits in a high mileage engine and you can load up the oil filter with solids pretty quickly. When this happens, oil consumption will tend to go up significantly .... After six months, I like to see: TBN > 6.0, using ASTM D-4739 test protocol Total Solids < 0.4%, or Oxidation/Nitration < 20 abs/cm Viscosity @ 100C, within +/- 10% of baseline Fuel < 1.5% NO Ethylene Glycol Water < 0.2% Silicon < 10 ppm You will probably see some high, residual lead and iron levels from oil pan deposits, but thats' perfectly normal....
Hi, my experience with this oil (Delvac 1) in petrol engines suggest that an annual OCI (15-20k) should be expected. This oil's viscosity and TBN retention is usually excellent I do NOT think you will need an interim filter change either as you can normally go twice the manufacturer's recommended interval with a synthetic oil if the engine is in good condition (see UOA recommendation below) As "TooSlick" has suggested and you acknowledge, a mid term UOA is a good idea Check under "Porsche" in the UOA section to see a six month report there Regards Doug MY02 Subaru Outback 2.5 manual (Delvac 1 20kkms OCI) MY98 BMW Z3 2.8 manual (Delvac 1 annual OCI) MY89 Porsche 928 S4 Auto (Delvac 1 annual OCI)
If you only want to change once yearly, D1 is the way to go. At 15k a year, I would consider 2x/year like I do with GC driving 20k a year. I consider 1x a year changes to be ok for old ladies and non-car people, I want better for my car. Generally, I plan on 2x changes a year for most people and adjust oil quality for miles driven, value of the vehicle and budget. PS I don't do interim filter changes.
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