Hammer Time: What's In Your Oil?

Steven Lang
by Steven Lang
hammer time what s in your oil

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.

Join the conversation
2 of 65 comments
  • 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 BTW I thought this silly thing was always called the "Wienermobile".
  • Tassos I have a first cousin with same first and last name as my own, 17 years my junior even tho he is the son of my father's older brother, who has a summer home in the same country I do, and has bought a local A3 5-door hatch kinds thing, quite old by now.Last year he told me the thing broke down and he had to do major major repairs, replace the whole engine and other stuff, and had to rent a car for two weeks in a touristy location, and amazingly he paid more for the rental ( Euro1,500, or $1,650-$1,700) than for all the repairs, which of course were not done at the dealer (I doubt there was a dealer there anyway)
  • Tassos VW's EV program losses have already been horrific, and with (guess, Caveman!) the Berlin-Brandenburg Gigafactory growing by leaps and bounds, the future was already quite grim for VW and the VW Group.THis shutdown will not be so temporary.The German Government may have to reach in its deep pockets, no matter how much it hates to spend $, and bail it out."too big to fail"?
  • Billccm I had a 1980 TC3 Horizon and that car was as reliable as the sun. Underappreciated for sure.
  • Inside Looking Out I did not notice, did they mention climate change? How they are going to fight climate change, racism and gender discrimination. I mean collective Big 3.