Hammer Time: What's In Your Oil?

Steven Lang
by Steven Lang

Two hundred thousand miles.

It’s a beautiful moment for many a car owner.

As for me? Well, I admit that I cheated when I saw that number flash by in my wife’s car back in March. Like many an enthusiast, I had bought it used and was planning on keeping her daily driver for the long haul.

The question for me was, “How long would the long haul be?” Since I buy, fix and sell a lot of vehicles, and have deeply imbibed the fluids of wisdom at the Bob Is The Oil Guy web site, I decided to live my life on the wild side.

I performed an oil analysis.

What I got back was a smorgasbord of technical information, and one pithy summation that went like this.

“STEVE – 200,000 miles? Please! This engine’s still a spring chicken. Metals look great here, so assuming she’s still running well and you’re not having any problems, then there is nothing about this sample that seems troublesome at all. Averages are based on about 7,600 miles on the oil. You could run your oil a bit longer, for sure. The TBN is kind of getting low (it’s down to 1.4 and 1.0 or less is low), but the TBN tends to drop more slowly the more use an oil sees, so it might hang on at this level for a while. The viscosity was fine assuming you used a 5W/20. Try 9k miles.”

I loved the spring chicken part. Boy that made my day. However that whole TBN remark threw me for a loop.

And what in the heck was a TBN in the first place? The BAD number???

Well, that’s when my quest for knowledge became a great big time suck. I went here, and later here. It was that second “here” which truly opened my eyes to what that TBN comment actually meant, and why I probably don’t want to delve any deeper into the inner workings of motor oil.

My engine was great. Case closed. Barring any unusual events, I was good to go for many more miles. I could extend my oil interval to 9,000 miles from 6,000 miles with a synthetic blend. Or maybe I could do a full 15k with a high performance full-synthetic engineered for longevity.

Mobil 1 EP? Amsoil? Deep Purple? Sorry.

The sad fact is that my wife drives a common-as-kudzu Prius with a light foot, and enough driving distance for the engine to always warm up. The local shop charges $20 for a synthetic blend and a quality filter. My net savings would be maybe $5 if I did it myself once a year with synthetic (her car holds a little less than 4 quarts.)

I spent $25 to figure all this out. So much ado about nothing. It was time to take the thermometer out of the motor oil, and worry about one less thing in my life.

My technical results are highlighted here. In the world where enthusiasts have to deal with the economics of keeping a car for a long time, an oil analysis can help you answer the uncertainties of a valvetrain’s health. But chances are, if your oil is regularly changed and you use products that are API-certified, there are better ways to spend your money.

If your car quits, chances are it won’t be your oil’s fault.

Steven Lang
Steven Lang

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  • SCE to AUX SCE to AUX on Apr 30, 2014

    I've only seen two engines internally ruined: 1. My friend's Dodge Intrepid 2.7, which spun a bearing at 70k miles. No surprise there. 2. My other friend's 95 (?) Buick 3.8, which spun a bearing when the plastic timing gear teeth sheared off, traveled to the oil pan, and he restarted the engine after repairing it without cleaning out the pan. This car had about 80k miles. Better oil wouldn't have saved them, but better engineering might have.

  • Terrence79 Terrence79 on Mar 31, 2017

    Great write-up. I'm using the Amsoil 5w-30 alongside the nano-based Everglide EGS and I'm pretty impressed with this combination. I'm happy using Amsoil alone before, but my mpg has increased when I started using Everglide. It made my driving smoother and quieter too. Oil is indeed a huge factor in the longevity of your car.

  • Tassos Under incompetent, affirmative action hire Mary Barra, GM has been shooting itself in the foot on a daily basis.Whether the Malibu cancellation has been one of these shootings is NOT obvious at all.GM should be run as a PROFITABLE BUSINESS and NOT as an outfit that satisfies everybody and his mother in law's pet preferences.IF the Malibu was UNPROFITABLE, it SHOULD be canceled.More generally, if its SEGMENT is Unprofitable, and HALF the makers cancel their midsize sedans, not only will it lead to the SURVIVAL OF THE FITTEST ones, but the survivors will obviously be more profitable if the LOSERS were kept being produced and the SMALL PIE of midsize sedans would yield slim pickings for every participant.SO NO, I APPROVE of the demise of the unprofitable Malibu, and hope Nissan does the same to the Altima, Hyundai with the SOnata, Mazda with the Mazda 6, and as many others as it takes to make the REMAINING players, like the Excellent, sporty Accord and the Bulletproof Reliable, cheap to maintain CAMRY, more profitable and affordable.
  • GregLocock Car companies can only really sell cars that people who are new car buyers will pay a profitable price for. As it turns out fewer and fewer new car buyers want sedans. Large sedans can be nice to drive, certainly, but the number of new car buyers (the only ones that matter in this discussion) are prepared to sacrifice steering and handling for more obvious things like passenger and cargo space, or even some attempt at off roading. We know US new car buyers don't really care about handling because they fell for FWD in large cars.
  • Slavuta Why is everybody sweating? Like sedans? - go buy one. Better - 2. Let CRV/RAV rust on the dealer lot. I have 3 sedans on the driveway. My neighbor - 2. Neighbors on each of our other side - 8 SUVs.
  • Theflyersfan With sedans, especially, I wonder how many of those sales are to rental fleets. With the exception of the Civic and Accord, there are still rows of sedans mixed in with the RAV4s at every airport rental lot. I doubt the breakdown in sales is publicly published, so who knows... GM isn't out of the sedan business - Cadillac exists and I can't believe I'm typing this but they are actually decent - and I think they are making a huge mistake, especially if there's an extended oil price hike (cough...Iran...cough) and people want smaller and hybrids. But if one is only tied to the quarterly shareholder reports and not trends and the big picture, bad decisions like this get made.
  • Wjtinfwb Not proud of what Stellantis is rolling out?
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