Join the Car Talk Community!

Discussion Rules

Welcome to the Car Talk Community!

Want to ask a question or join the discussion? Great! Join now.

Sign In Register

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.
  • edited January 2013
    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 30*F and OW20 was actually not specified unless the temperature could drop below 0*F 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.
This discussion has been closed.