Is changing oil viscosity after 7 yrs a bad idea?

[nicholasmari]

About 7 years ago someone suggested to me to use 10w-30 in my car instead of 5w-30. The reasoning was with higher mileage a heavier oil would offer a little more protection, which made sense at the time, so with that, along with the fact that I live in Southern California, I've been in the habit of using 10w-30. I drive a 1998 Honda Prelude and the manual recommends 5w-30, but states 10w-30 is okay. I would like to switch back to 5w-30, but I am wondering if that is a bad idea after using 10w-30 all these years? I know once heated up there is little difference, but I am wondering if any components of my engine may have gotten dependent on a heavier oil?
Thanks, Nick

 

[rg200amp]

Welcome to BITOG!!!!!


5w30 and 10w30 are BOTH 30 weight oils.

They are the SAME weight at operating temp.

You will have NO issues whatsoever!!

 

[440Magnum]

Once heated up there is NO difference (for all practical purposes) between two 30-wt oils like 5w30, 10w30, and 0w30. Its quite possible for a high viscosity index 0w30 to be thicker at operating temp than a low VI 10w30 although its not common. Also, the engine doesn't "get used" to a grade and then feel sick when you change grades anyway. Its metal, it doesn't have feelings. ;-)

 

[rg200amp]

Originally Posted By: 440Magnum
Also, the engine doesn't "get used" to a grade and then feel sick when you change grades anyway. Its metal, it doesn't have feelings. ;-)



True in most cases, including this one.

However, in some highly sophisticated Variable Valve Timing systems, a major change in oil weight *could* cause slight issues until the computer remaps the air and fuel mixes.

 

[nicholasmari]

Thank you for your replies. That's what I thought, I asked because someone suggested the clearances and bearings may have loosened and be use to 10w-30, but I didn't think that made sense.

 

[Mau]

You are fine! nice car (had a 99 lude), it got PP 5w30 majority of its life.

 

[TFB1]

Originally Posted By: nicholasmari
Thank you for your replies. That's what I thought, I asked because someone suggested the clearances and bearings may have loosened and be use to 10w-30, but I didn't think that made sense.


It does not, because at operating temp the oils are basically same... It's when cold you actually have thicker oil, which does no good at all...

 

[scurvy]

Your engine could not care less - they are both in the same viscosity at operating temperature (30 weight). If anything the 5w30 will let the oil flow easier at 'cold' startup but after 15 years it won't make a lick of difference.

Drive more, worry less!

 

[Steve S]

Why would you want to switch if all is well?

 

[Artem]

Yea why the sudden desire to switch?

 

[fdcg27]

This thing is a Honda, and it couldn't care less what oil grade you put in it.
We've had six of them over the years, two with VTEC, and they ran fine on anything from 0W-30 to 15W-50, including the VTECs, some past 200K.
Why not just stay with a 10W-30?
OTOH, a 5W-30 will be just fine as well.
Use whichever you'd like.
The engine will not suffer either way.

 

[yaris0128]

Although theres nothing wrong with what your doing Mobil 1 has quite the winner with its 0w30. It makes perfect sense to buy that oil over 5w30's or what have you.

 

[NismoMax80]

After 7 years of 5w30 I switched to 0w40!!!!

feeling good about it too.

 

[PontiacFan]

Originally Posted By: rg200amp
Welcome to BITOG!!!!!


5w30 and 10w30 are BOTH 30 weight oils.

They are the SAME weight at operating temp.

You will have NO issues whatsoever!!







+1

 

[OldCowboy]

Originally Posted By: NismoMax80
After 7 years of 5w30 I switched to 0w40!!!!

feeling good about it too.


Yeah, but your engine's about to puke!

Just kidding.

 

[Gene K]

When 5W30 first became popular with the low viscosity index of the base stock and lower quality of the VII of the day they sometimes sheared excessively. Assuming the person recommending 10W30 actually new something about oil this is likely the reason they recommended 10W30.

With the better base stock and VII today this is less of an issue. In many cases the 5W30 has a higher VI base stock so is no more shear prone than 10W30. Thats outside the designed in shear to get the energy conserving rating.

 

[440Magnum]

Originally Posted By: nicholasmari
Thank you for your replies. That's what I thought, I asked because someone suggested the clearances and bearings may have loosened and be use to 10w-30, but I didn't think that made sense.


When I said the engine wont "get sick," I meant it... but that doesn't mean you won't observe things like a change in cold oil pressure going from a 10w30 to a 5w30. If the gauges are sensitive enough and the oil pump volume and clearances are just right, you may very well see a different oil pressure at cold idle, for example. But that's harmless unless the oil pressure gets out of spec.

What I meant was, you'd have seen the same change 10,000 miles ago. The clearances don't "adapt" to the grade of oil used.

 

[440Magnum]

Originally Posted By: Artem
Yea why the sudden desire to switch?


I can think of one good reason: for the most part, 10w30 is an orphan grade, just like 10w40 was 30 years ago. It doesn't get the best base stocks, doesn't have high VI, and generally is not the place where the most modern oil technology is applied. That's not to say you cannot buy a superb 10w30 oil, you most certainly can if you specifically look for one. But if you sorta average across all the oils sold, IMO the 10w30s tend to get the short stick. And besides, there's just to REASON to use it anymore unless you own an engine that just happens to respond better to thicker oil when its cold. But odds are if you need a thick oil when cold, you need one even worse when hot and should be running an Xw40 or Xw50. JMO.

 

[tommygunn]

yea, some people just don't understand the 10W vs. the 5W.....that's the oil weight at initial startup.....if anything, the older vehicle would prefer a 5W, so the oil can get to where it needs to go, quicker