NMA Article: Oil Change Essentials
By Eric Peters, Automotive Columnist
You may not change your own oil, but if you’re thinking about learning to do this basic DIY job to save some time and money — or just want to know enough to be able to judge the quality of the work done by someone else — you might find the following tips and suggestions handy to have:
* Engine oil should always be changed with the engine warm — but not hot.
If the engine’s too hot, you risk serious burns, not just from the hot oil but also from coming into contact with hot exhaust pipes and so on.
If the engine’s too cold, the oil will not drain quickly — and worse, a good portion of the contaminants you’re trying to get out of there will be sitting in sludge at the bottom of the pan instead of carried out of there with the draining oil. Enough sludge may remain in the bottom of the oil pan to contaminate the fresh oil/filter you just installed. You also risk over-filling the crankcase — by assuming the usual 4-5 quarts have in fact drained when in fact there’s still half a quart or more of dirty oil/sludge inside the pan that didn’t drain off.
The best time for an oil change is about 10-15 minutes after a 15-20 minute drive. The drive is long enough to warm up the engine and facilitate thorough drainage of the old oil and the contaminants it is holding in suspension. And the wait is just long enough to allow things to cool down sufficiently so that you won’t get burned by hot engine parts or scalded by boiling oil.
* Let the old oil drain completely.
One of the things I don’t like about some “quickie lube” places is that they are in such a rush to get the job done. Sometimes, they don’t let the old oil drain completely — and reinstall the pan drain plug even as old (filthy) oil is still dripping out. You want to get as much of the old oil out as will drain out — both from the drain plug hole in the oil pan and the filter’s spin-on fitting. When you do it yourself, you can take five minutes for a beer break while the oil is draining — and reinstall the pan drain plug only after there’s no more dripping. When you take your car to a quick-lube place, ask that they do the same — and watch to see that they do.
* Use only high-quality oil — and filters.
An oil change is not the place to cheap out. All oil — and all oil filters — are not created equally. With oil, staying safe is fairly easy. So long as the weight is correct and the oil in question is stamped with the minimum API service grade specified by the people who built your car (see your owner’s manual for this info, under “maintenance”) you will be fine. Brands — and even prices — are not critical, so you can shop around for the best deal.
It’s not so simple with filters. Some have proved to be horrifically poor quality — for example, delivering little to no effective filtration or having a filter material that disintegrates shortly after you install the filter, leading to a plugged filter (and no filtration at all) or filter debris circulation throughout your engine.
Unfortunately, some name brand filters have been implicated. A google search of the filter brand you’re shopping plus the words “defect” or “problem” will help you ID the bad ones pretty quickly. To stay absolutely safe, either use (or be sure your lube shop uses) only filter brands specifically recommended by the company that built your car — such as “Genuine GM” AC Delco for GM vehicles — and so on.
* If possible, at least partially fill the new filter with fresh oil before you install it.
The oil inside your engine is circulated by a pump usually located in the bottom of the oil pan. After you’ve drained the oil, it takes the pump several seconds to build pressure and pump oil throughout the engine.
If the new filter is installed dry, the oil pump has to force it full of oil — and push out the air inside it — which means it takes longer to get up to normal pressure and establish full oiling throughout the engine. This in turns means that vital (read: expensive) engine parts may not be getting sufficient lubrication, with the result being accelerated — and totally unnecessary — wear and tear.
Pros avoid this by pouring at least some fresh oil into the filter prior to installation. As long as the filter isn’t mounted onto the engine with its open end facing down, you can usually fill the filter half way up or more with oil before installing it — without spilling the oil all over the engine.
Don’t forget, incidentally, to wipe clean the mounting pad, making sure the old gasket came off with the old oil filter. And also, wipe a thin coat of fresh oil onto the new oil filter’s rubber gasket before installation to assure a leak-free seal. This will also help the new gasket release easily when the time comes for the next oil/filter change.
* Be gentle with the filter and the pan plug.
Beginners often make the Too-Tight mistake and buy themselves leaks and a lot of trouble. Most oil filters are designed to be installed “hand tight,” a half-turn or so after the filter gasket contacts the mounting pad surface (see your owner’s manual or a service/repair book for your specific vehicle to get the exact procedure for your specific car).
Avoid using a filter wrench unless the filter is very hard to reach with your hand or you just don’t have the grip strength for hand-tightening. If you overtighten the filter, you risk compressing the rubber gasket excessively — which will lead to a big mess on your garage floor when you start the engine. Even if it doesn’t leak, it’ll be much harder to get that old filter off next time.
Finally, the drain pan plug. Be very careful not to cross-thread it — or over-tighten it. Few things can ruin your day more than ruining the threads in your oil pan. To fix it, you might end up having to remove the oil pan — which might require removing the engine from the car in some cases. All because you messed up a $5 oil drain plug.
To avoid this debacle, use your fingers to thread the bolt — not a socket and wrench.
Once it’s hand-tight, use a wrench/socket to gently tighten it down. Experienced DIYers know how to do this by feel. You may want to use a torque wrench to be absolutely sure. A $35 torque wrench could save you a $300 repair bill for pulling and fixing a damaged oil pan.
Be sure, also, that the nylon or copper washer is on and undamaged. If it’s broken or looks like it’s about to fall apart, stop what you’re doing, make a run to the auto parts store and get a new replacement washer. It is there for a reason. Do not reinstall the drain plug without the washer.
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Oil Change Essentials
Further Reading: © 2009 NMA