Las Oil Change I used 5w-30 instead of 5w-20

Last oil change I did it myself for the first time on my wife’s 06 Honda Odyssey. I used 5w-30, like I use in my Lexus, instead of the recommended 5w-20. This was the first time her car was switched to synthetic Mobil 1, but now the engine sounds louder and not smooth as usual. Did I do something wrong? She has already put on 1,000 miles since the last change, and the car has about 110,000 total miles. Other then that the car seems to be running fine but I don’t want to kill the engine.

I don’t think going from 5W-20 to 5W-30 would make the engine noisier or run less smoothly. If you aren’t imagining this, then something other than the viscosity of the oil is causing the engine to run noisier and less smoothly.
Years ago, I had the engine become noisy on a 1985 Ford Tempo. The hose from the air cleaner to the fuel injection system had come off. If, in fact, your engine makes more noise, look under the hood and see if the air intake hose is in place or some other obvious thing has happened.

I agree with Triedaq. If anything, switching to 5W-30 from 5W-20 would make the engine quieter.

I had the opposite happen once–5W-20 was put in the car instead of the specified 5W-30. It was in the winter when this happened. I didn’t think it would hurt anything. We even made a 700 mile road trip. I kept my eye on the oil level, but none was used. In your situation, I am certain that nothing bad will happen due to putting in 5W-30 oil. At your next oil change, just put in the 5W-20.

The bearing clearances are designed for 20w oil and using heavier or higher viscosity oil will result in less flow to bearings. This may or may not affect bearing life and I do not think it will cause harm. But, why not drain oil and put in 20w and see if noise changes?

How cold will it get at your house this winter, scooter? If the temperature never drops below ZERO you are most likely OK. If the temperature never drops below freezing your engine my benefit from that grade.

I’m a mechanical engineer, and have an extensive background in engine lubrication system design for a major auto manufacturer (not Honda). I strongly recommend that you use the grade of oil recommended by the manufacturer. You may not be at risk of engine damage by using 5W-30… but then again it’s possible that you are.

For example:
5W-30 will be thinner than 5W-20 as oil temperature drops below 0C, which could result in insufficient bearing film thickness on cold starts.
On the other hand, 5W-30 will be progressively thicker than 5W-20 as operating temperatures increase. The performance of hydraulic systems (such as the variable valve timing system used on your vehicle) is affected by fluid viscosity. It’s possible that the engineers specifically chose 5W-20 because the thinner operating viscosity enables faster response of the spool valve and locking pins. If using 5W-30 results in the risk of the pins not being able to engage fast enough, then you’re at risk of valvetrain damage.

I have no knowledge that either of these examples is actually the case on your particular engine, but these certainly ARE the kinds of design and development details that go into the selection of oil grade. There are many such issues, and the system interactions are very complex. Do yourself a favor: don’t second-guess the engineers.

Welcome, chilehed, to our forum. We routinely get questions on oil grades and on the differences between dino oil and synthetic oil, and your expertise will be a blessing.

@chilehead, don’t you think you may be overreacting?

Millions of Ford owners put 5w30 in their vehicles without ill effect.
And we know that 5w20 is called for.

db4690, I don’t think that the OP needs to panic, but I also don’t think I’m overreacting. It’s not really possible here to give an adequate explanation of why… my opinion is the bottom line of a lot of experience. Is it possible that you might be able to get away with using an off-spec oil? Sure. Is it a good idea? No.

I don’t put any additives in my oil, either.

As we beat this dead horse I remain curious regarding the manufacturer’s climate specific recommendations regarding oil. Whenever I have taken the time to dig beyond the obvious I have found that manufacturers have temperature/viscosity charts that are relatively equal with respect to the most popular viscosity grades. I recall a Lexus chart that clearly specified straight 30 weight oil when temperatures were never below 30F and OW20 was actually not specified unless the temperature could drop below 0F while not exceeding some not so extreme high temperature. Why don’t the manufacturers make their climate specific recommendations available to the public as they did for so many years? I recall the 1950s Willys manual specifying diluting 20W oil with kerosene when temperatures dropped below 0*F. As I opined earlier here, if the temperature is mild 5W30 would most likely be the better choice and 10W30 better still.

I found this quite interesting…

And how do we know that millions of ford owners use 5w-30 when they should be using 5w-20? Oh yeah, Obama won so there are millions of idiots out there

I will do my utmost to avoid inpeding any of you wealthy people who will hopefully fund my SS checks. Some of us might live a few years past 65 and we hope the Republicans will forgive us. I am gratefull that the SSA doesn’t ask who I voted for.


Why’d you have to bring politics into this?

@chilehed Your statement is generally true, but many oil specs by car manufacturers are partially driven by CAFE requirements, and using a thinner oil will squeeze that extra fraction of a MPG on the test, at the expense of long term engine life. My Toyota book says to use 5W30, but two years later I got a bulletin to use 5W20 mineral base or 0W20 SYNTHETIC.

My son’s Maxda3 says to use 5W20, but this same car in other countries will use anywhere from 5W30 to 10W50 (not recommended) in some tropical countries. My son diregarded the book and uses 0W30 full synthetic and after 110,000 miles of hard driving, some of it in the SW desert, the car consumes virtually no oil between changes. No European car manufacturer specifies 0W20; that would not work at 100 MPH on the Autobahn.

Oil recommendations are of necessity a compromise between minimizing friction (and maximizing EPA mileage) and preventing undue wear. My wife’s new Mazda specifies 0W20 synthetic, and the dealer will not put in anything else. I would be OK with a 0W30 (we have cold winters here), since cold start engine wear can be severe. However, my wife will not race across Arizona in July.

I agree with you that it is unwise to put in an oil that’s too heavy and won’t allow the valve gear to be operated properly.

The only real difference in 5W20 and 5W30 is the amount of friction modifiers added to the base oil. Friction modifiers are actually microscopic coiled polymers that uncoil as they heat, increasing the viscosity of the mix as a whole, thuse maintaining its resistance to flow as the temperature rises. The more modifiers, the better the oil maintains its viscosity.

The problem is that these modifiers do not have the same lubricating capabilities as the base oil. In critical conditions, such as tight spaces, timy orafices, and high stress spots where, for example, vectored forces can cause perhaps an axially-operating deviice to operate at an angle, or perhaps a laterally loaded spot like a rod bearing to need all the lubricating possible, it might theoretically make a difference. Perhaps there are also variable valve situations such as small orafices where it might make some difference, seeing as how it’s used in modern engines as a hydraulic fluid as well as a lubricant and heat remover.

I thus truely believe in usng the right oil. Having said all that, I seriously doubt that 5W30 instead of 5W20 did any damage.

The Odyssey has variable valve timing; the heavier weight oil could be causing trouble with its operation.

Edit: Nevermind, I see that chilehed already mentioned that.

chilehed, I am surprised that with your experience, you did not have a pat answer to the question. Also you say 5W-30 will be thinner than 5W-20 as oil temperature drops below 0C,
Isn’t that the opposite of the fact?

In the time we have spent debating this, he could have just changed the oil like I would have done and chalk it up to experience. I’m not an engineer so I just use what the book tells me to use and if I put the wrong stuff in, I’d just change clothes again and redo it. You got me worried on 0-20 though in my Acura but I don’t plan to drive 100 mph with it.