Rich’s Repair Ramblings #9: Ten Steps to a Better Oil Change

Changing the engine oil and oil filter is one of the easiest and most straightforward maintenance jobs you can perform on your collector car. What’s easier than “pull the drain plug, swap out the filter, and add new oil”? Would it surprise you if I said that I might be able to offer up to 10 suggestions to improve the process? The following 10 Best Practices are from my own experiences. Read through the list and see if there isn’t at least one step which you can incorporate to make the next oil change a better one for your buggy.

#1. SAFETY FIRST!

It bears constant repetition: Never work under a car that isn’t properly supported. Do not use the vehicle jack (or worse, some cinder blocks) to support a car off the ground. Use quality jack stands or drive-up ramps with sufficient weight ratings when doing any work that involves sliding under something that weighs upwards of several tons. Make sure that the transmission is either in “Park” or for stick shift cars, in a forward gear. Always set the parking brake. Chocks on the rear wheels are a good idea too.

#2. DRAIN THE OIL WHEN THE ENGINE IS WARM.

Yes, “cold” (room temperature) oil will flow out the oil pan. But warm oil flows more quickly, and more importantly, takes more contaminants out with it. The engine doesn’t need to be hot – you increase the risk of burning yourself from scalding oil or a hot exhaust pipe. But if the car is cold, let it idle at least until the temperature gauge starts to move. If you don’t have a gauge, 5 minutes on a warm day should do it. If you’ve just driven the car and everything is too hot to touch, wait 20 to 30 minutes so that the oil is warm but not burning hot.

#3. REMOVE THE FILLER CAP BEFORE YOU REMOVE THE DRAIN PLUG.

You’ll get faster flow (and again, remove more of the bad stuff) if you take off the oil filler cap and allow air into the engine during the drain. The cap needs to come off anyway! This is the same as punching a 2^nd hole in a can when you’re trying to pour out liquid.

#4. REPLACE THE DRAIN PLUG WASHER.

The drain plug has a gasket or washer, typically made of copper or aluminum, which serves as a seal. The softer metal is designed to be crushed when you tighten the plug. But the washer can stand being crushed only so many times before it’s no longer effective at stopping leaks. The trick in replacing the drain plug washer is having a spare one on hand. (I buy them by the dozen.) And a tip to avoid a problem that even trips up the pros: make sure that the OLD washer is removed, and is not stuck to the drain plug or oil pan. If you put a new washer on the drain plug with the old one there, you’ll almost certainly have a leak.

#5. ALWAYS REPLACE THE OIL FILTER.

I continue to be amazed at the number of times that someone has told me that they completed an oil change and left the old filter in place. What is the issue? Is the filter difficult to access? Is it too expensive? Do you think that the old filter has some service life left in it? If it’s hard to get to, watch some YouTube videos and figure it out. Others have. How much does a new filter cost? Stop being so cheap. Leaving the old filter in place recirculates about a quart of dirty oil directly into your fresh clean oil. It also runs the risk of the filter becoming so full of contaminants that it can no longer do its job. Always be sure to have a new filter on hand before you start the job.

#6. PRE-FILL THE OIL FILTER BEFORE INSTALLING IT.

This is one ‘best practice’ that isn’t always practical to do. I do this for one car, but not the other, simply because of the filter’s location. If the filter attaches from the bottom, I can add oil to it and keep it right-side-up, avoiding any spills when reinstalling it. However, if the filter attaches horizontally, it’s trickier. Sometimes I can add a little oil and get it on there without any spills. We’ll need to qualify this best practice with the caveat “it depends”. See Tip #9 below.

#7. TIGHTEN THE OIL FILTER CORRECTLY.

A while back, my neighbor had to return her car immediately after an oil change, and she was told that the tech had left the filter loose. (The person performing the job also needs to make sure that the rubber gasket from the old filter is not stuck to the engine block, for if it is, the new filter will never seal properly.) It’s just as bad, however, to overtighten the filter. I have personally witnessed technicians resort to hammering a long screwdriver through an old filter to act as a pry bar to remove an overtighened one. For most cars, oil filters should be tightened by hand, without the use of any tool. Tighten until the gasket contacts the engine, then turn the filter another 1/8 to ¼ of a turn. That’s it!

#8. USE THE CORRECT VISCOSITY OIL.

Your owner’s manual will identify the specified viscosity. For most cars built in the last 50 years, vehicle manufacturers have recommended a multi-weight oil good for year-round use, with numbers like “10W-30”. The lower the number, the thinner the oil, necessary in cold weather. The higher the number, the thicker the oil, needed in hot climates. The “W” stands for winter. Using the incorrect viscosity oil can damage the engine in your old car. My Alfa Romeo calls for 20W-40 oil, but that was printed in 1967. It runs very happily (and uses no oil between changes) on 20W-50. At the other extreme, my modern iron specifies 0W-20. It would be a disaster if I were to switch these viscosities between the old and new cars! As a special note for much older AACA cars, the called-for viscosity may no longer be readily available. If your engine has been rebuilt, you may need to adjust the viscosity you use compared to what was recommended 70 or 80 years ago. Speak to other owners with similar cars to see what they use or recommend.

#9. CRANK, BUT DON’T START, THE ENGINE TO BUILD UP OIL PRESSURE.

Starting an engine immediately after an oil change runs the risk of starving critical components like bearings of needed oil. A best practice is to disable the ignition (easy on old cars by simply pulling the secondary coil wire) and cranking the engine until oil pressure builds, usually in about 5 to 8 seconds. Taking this small step helps ensure the longevity of internally lubricated engine parts.

#10. RECHECK THE OIL LEVEL 5 MINUTES LATER.

The manual states “five quarts with filter”, and that’s what you put in. But I don’t rely solely on the number of quart bottles I’ve poured. After running the engine for a few minutes, I shut it down, wait 5, then pull the dipstick (with the car on level ground). If it needs a smidgen more, now’s the time to do it.  I want the peace of mind of knowing that, after an oil change, the level is exactly at the ‘full’ mark on the stick.

All photographs copyright © 2023 Richard A. Reina. Photos may not be copied or reproduced without express written permission.