Piston Slap: Dodging Trouble With Synthetic Oil?

Sajeev Mehta
by Sajeev Mehta

Tom in North Carolina asks:

Sajeev, my 2005 Dodge Durango (4×2 Limited with Hemi and tow package) hit a critical juncture in April. The truck hit 70,000 miles meaning the 7/70 power train warranty expired, and Chrysler just BK’d. Since the vehicle is in great shape, good for road trips, is all but paid for, and is worth less to a dealer than it is to me, I plan to keep it for awhile. I have been told the 5.7 with the 5 speed auto is a fairly bulletproof power train, and with proper care and feeding should last a long time. The truck gets no severe service and is driven fairly gently, 70/30 highway/suburban use, 18,000 miles per year.

To keep it running I am debating keeping with the OEM scheduled 5000 mile oil changes (usually available for about $22) or switching to Mobil One at 10k or 15k change intervals. If I switch to synthetic oil, would you suggest a “better” quality oil filter (and what brand)?

Sajeev replies:

Obviously you should buy a brand spankin’ new Durango and use nothing but the cheapest stuff in it. When component failure comes knocking, suck the taxpayers dry with Ceberus’ lifetime powertrain warranty.

But seriously: the OEM oil chosen is a synthetic blend, which is more than adequate for most needs. I do prefer switching to Mobil 1 (or comparable) and extending the service interval to 6,000–10,000 miles, depending on your driving conditions (traffic, speed, etc.) and regional climate. So you can’t go wrong with either setup unless you plan on keeping this SUV forever, far past 200k miles. Then switch to synthetic.

Another often overlooked concern: make that switch to synthetic ASAP. As motors get older and tolerances between gaskets loosen, the thinner molecules of synthetic are known to cause oil leaks. You should be fine at your mileage, however.

As far as filter recommendations, this website does a great job presenting the engineering specifications of leading oil filters. But as TTAC commentator Tosh once mentioned, their/my recommendations do not include testing with before/after oil analysis.

I use Wix, Purolator PureOne, and Mobil 1 filters on my personal vehicles on 6-10k oil change intervals: the Mobil 1 filter is only used on the ones with seriously expensive engines that see more, umm, demanding amounts of throttle. I use Wix more often mostly because of price and availability at my favorite parts store. Frankly, any of the more expensive filters (no orange cans of death, please) is fine for your switch to synthetic.

[send your technical questions to mehta@ttac.com]

Sajeev Mehta
Sajeev Mehta

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  • Windswords Windswords on May 19, 2009

    By the way, if you decide to go with the 10k mile oil change interval as I detailed before you should: Buy any oil filter you want (and trust) for the first 5k that's on sale. Buy whatever you think is the best oil filter that you can easily get for a reasonalble price (in my case I use Purolator PureOne). Use a synthetic or synth blend you trust (and more importantly have researched). Check your oil regularly to make sure you are not burning/losing oil (this is after all, a longer change interval). And most important do an oil analysis after a few changes to see how it's doing for your vehicle. For those who wish to save money, you can create your own synth blend. Just take 1 or 2 qts of synth (I think 1 qt is plenty), and 2 or 3 qts of regular. Make sure they are the same viscosity rating and are from the same company. That way the additive package will be the same/similar. I haven't priced it recently but, for example I believe that 1 qt. of Castrol Syntec plus 3 qts. of regular is cheaper than 4 qts. Castrol synth blend, but you will have to see for yourself.

  • Eric Bryant Eric Bryant on May 19, 2009

    @ Lee - How did you pick your oil change interval of 5,000 miles? That'd be twice as often as required by my wife's V6 Accord - but half as often as required by the engine in my Impala. My point is that there are three approaches: 1) Stick with the manufacturer's recommendations; 2) Obtain scientific analysis of your vehicle's oil and use it to establish a change interval; and 3) Witchcraft and guesswork. A suprising number of enthusiasts appear quite willing to take approach #3.

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