I just drove my old Jeep on a 500 mile trip to and from Las Vegas, home of the legendary SEMA car-parts industry trade show, and the thing drove beautifully. But that was not always the case; in fact, for the first six months that I owned this Jeep, it ran like a dog (which I’m realizing is a strange expression in the car-world given that dogs actually run…rather well?). That’s because I foolishly didn’t conduct my usual “just bought this car” wrenching routine.

I’ve been buying old junkers for a very long time now, and there are certain things that I do to all of them as soon as I get them home to my garage. The most important thing is: I change the fluids.

Automotive fluids’ job is too important to ignore. Dirty fluid can kill your engine, transmission, transfer case, and axles, plus it can corrode brake system and cooling system parts. Why take that risk? It’s not worth it.

For this reason, anytime I buy a new vehicle, I always change the oils. That means: engine, transmission, transfer case, and differentials. Even though I didn’t have time to do my full barrage of initial tinkering, and thus the Jeep drove like a dog (like a dog drove? That would make more sense), I refused to forego changing fluids even if that meant wrenching on a diff in my work clothes:

While changing the fluids, I found that my transfer case was completely bone dry. Could you imagine what would have happened if I hadn’t done my fluid check, and instead drove 500 miles with a bone-dry T-case? That thing would be shot. As it sits, it’s working well, probably because it had been sitting a while prior to my purchase (and not driven much with the dry case).

I also changed my engine oil, transmission oil, and diff oil (I admittedly haven’t gotten around to the front diff, but that doesn’t see any torque during everyday two-wheel drive driving; still, I’ve got to get around to that), plus I checked my brake fluid, power steering fluid, and coolant (they looked good).

What I did not get around to was my usual “just-bought-this-car” tuneup job, which involves replacing the spark plugs, distributor cap, distributor rotor, and spark plug wires. These parts are cheap, and since they wear out and are critical to the vehicle running properly, I always just replace them on any vehicle I purchase.

The result of me not going through with my full just-bought-this-car strategy was that, for the first six months under my ownership, the Jeep bucked and banged under load, especially when taking off from a stop light. Honestly, it sounded like metal-on-metal contract; my initial worry was that something was wrong with my clutch/pressure plate.

But after I put in the $50 and 45 minutes to get the plugs and wires and distributor bits swapped out, the Jeep ran beautifully, and I now regret all those times I listened to that horrible pinging/banging; I should have just followed through with my fluids + tune-up + visual inspection of tires/brake pads/etc regimen.

Alas, the Jeep sounds great now, doesn’t seem to burn oil, and makes plenty of power, and I have the satisfaction of knowing that it will continue to drive like a dream thanks to fresh fluids and a nicely-running motor.

What do you do to a car once you buy it? Whether that means maintenance-wise, or perhaps you want to talk about some routine modifications you make to cars after you buy them.