Wrong Oil Viscosity

I have a 2002 Nissan Altima SE (3.5L V6) with 158,000 miles. It runs great and I have been changing the oil myself since day one with 5W30 High Mileage (after 75,000). I recently put 5W20 instead of 5W30 in it by accident. Should I be worried? Should I change it now or can it wait 3500 miles. I live in Charlotte, NC so the temperature will be moderate over the next 4 months. Thanks for the help.

It won’t damage your engine, just switch back to 5w30 next oil change.

The high number indicates thickness when warm, You may burn some oil before the next change but I would say let it go.

It’ll be fine. Check the oil level every couple weeks. You should do this no matter what oil is in there anyway.

It should be fine, but I think I would change it IF I were planing on a long trip on a hot day.

I did the same thing on our 2003 Toyota 4Runner. I did this in the fall. We even took a 750 mile round trip to see our son. This was a couple of years ago. The engine consumed no oil. I ran the 3000 miles and then changed to the right viscosity. You will be fine.

Not to worry, some of the 5W20 seems really thick to me when it pours from the container. I don’t see 5W30 causing any problems. Anybody who resigns from an oil company is probably assigned to quality control for his final week and is given unsupervised access to the office supply room. He spends most of his remaining hours packing boxes.

Relax, the worst that could happen is the oil will burn off a bit faster. The remedy is to check your oil level monthly and top off as needed. Don’t change your oil change interval. Just go back to the other oil weight at the next oil change.

To further reduce your anxiety, I remember reading an article in Popular Science back in the early 1950’s by Les Viland titled “How I Save Gas”. Viland won the Mobilgas Economy Run several times. One time he was driving a Lincoln. One trick he used was to put 5 weight oil in the crankcase. He didn’t blow the engine on the run. He did state that in his cars, he always ran 10 weight oil. This was back in the days when most cars reqired 30 weight oil in warmer weather.

Les was only concerned that the engine last 500 (or whatever) miles…

You could add half a can of STP to bring the 5w-20 oil up to 10w-30 viscosity…But the difference between 20 and 30 weight is not enough to worry about, especially in moderate temperatures…

Monthly? Weekly or bi-weekly at most.

I am certain I wouldn’t want a car after Les Viland owned it when he always ran 10 weight oil. On the other hand, Tom McCahill in his book “What You Should Know About Cars”, published in the early 1960s claimed to use oil one weight heavier than recommended by the manufacturer. I prefer to take the average of these two viewpoints and run what is recommended in the owner’s manual.

When I was in college and had gone out of town with a couple of other fellows. One fellow owned a 1950 Pontiac. When we were about 25 miles from campus, a rod bearing started knocking. We stopped at all night service station. The mechanic drained out the oil and put in 90 weight gear lube. We push started the car and made it back to campus. The next day a wrecker hauled the Pontiac to the cemetary for dead cars.

No problem; just stay out of Death Valley and don’t carry heavy loads or tow a trailer, or drive fast. Switch back to 5W30 at the next oil change; in the meantime, check your oil with every tankful of gas. Some engines really use oil when you put 5W20 in.

You might find out from your dealer or Nissan what weight they now recommend, and whether that recommendation is retroactive.

My 99 Honda Civic came with 5W30 recommended - but I found out a year or so ago that they now recommend 5W20 (which was at first a rare grade, but is now very common) for new engines and for mine. This was printed on a Honda USA multicolor document, so I believe it.

I prefer by miles, every 1k.

The age and type of engine and the age of the oil are the biggest variables. Mostly. If you’re just topping off a broken-in engine with moderately aged oil off with 5w-20, it probably would actually help the viscosity and loosen things up a bit…the dirtier the oil the more the viscosity gets reduced anyway. A lighter warm weight oil would give you a little more time before it got really sludgy in there. I’d be much more worried about a clean fill of the wrong oil on a newer racing engine than I would be a used and abused daily driver. More power comes with tighter tolerances and much more specific performance specs.

The person who asked this question 8 years ago has probably changed the oil at least 8 times by now.

Oh, I’m sorry. I forgot to say bump. No worries, people read this stuff all the time. Case in point

1 Like