15w40 again

[gingrasr]

Please bear with me for my ignorance but I need some information.
I own a 1992 Honda Accord with about 291,000 miles on it. The car runs well and looks relatively good.
Someone recently recommended using 15w40 for the summer due to its age and mileage.
Is this valid advice? Worth following?

Thanks for any help.
Richard

 

[glennc]

I would say not. A 15w40 is too heavy when cold, even in summer. The warm-up period for an engine even at "warm" outside temperatures is very important for wear and somewhat important for economy. There was a thread here a while back that made it clear that even on a 70 degree start, wear is 20-50 times greater than when the engine is warm. This appears to be a function of oil viscosity only, not oil temperature, so you are making the warm-up wear much worse by using an oil that is heavier at each point in the warm-up process than it needs to be.

I would use a high mileage oil of the recommended viscosity - that will give you very slightly increased viscosity, which might be a good thing, without throwing things unnecessarily out of whack, and perhaps some other benefits as well. Maxlife Blend is an excellent choice.

 

[dlafoy]

good post glennc

 

[JAG]

Originally Posted By: glennc
This appears to be a function of oil viscosity only, not oil temperature, so you are making the warm-up wear much worse by using an oil that is heavier at each point in the warm-up process than it needs to be.
The high wear was independent of viscosity. https://bobistheoilguy.com/forums/posts/1103737/

Quote:
Next are the effects of viscosity and oil temperature. Only ring wear was tested as they state it was most sensitive. They compared basic SJ GF-3 mineral oils. The additive packages were the same. The only difference was the viscosity of the base oils. The following grades resulted: 0W-10, 5W-20, 5w30, 10W-40. The HTHS for these oils were 2.17, 2.83, 3.09 and 3.76.

There was no difference in wear rates. The oils were tested at all RPMs and Loads, no difference between oil grades were noted. All the oils had increasing wear rates as the load increased but all increased at the same rate across the board.

 

[glennc]

The high wear was independent of viscosity grades, that is correct. However AEHaas pointed out that the relatively small differences in viscosity between different grades is unimportant compared to the differences in viscosity between startup temps and running temps. IIRC the most reasonable conclusion was that the viscosity was the main factor in increased wear, since the hot oil/cold engine tests did not show the excess wear that the cold oil tests did.

I'm going from memory here as I haven't had time to look at the link and re-read the thread, but I will later.

 

[gingrasr]

Thank you all for the information.

Richard

 

[TallPaul]

A 10w30 would be a decent choice for summer. Unless you have low oil pressure, no need to go any thicker.

 

[Gary Allan]

Originally Posted By: JAG
Originally Posted By: glennc
This appears to be a function of oil viscosity only, not oil temperature, so you are making the warm-up wear much worse by using an oil that is heavier at each point in the warm-up process than it needs to be.
The high wear was independent of viscosity. https://bobistheoilguy.com/forums/posts/1103737/

Quote:
Next are the effects of viscosity and oil temperature. Only ring wear was tested as they state it was most sensitive. They compared basic SJ GF-3 mineral oils. The additive packages were the same. The only difference was the viscosity of the base oils. The following grades resulted: 0W-10, 5W-20, 5w30, 10W-40. The HTHS for these oils were 2.17, 2.83, 3.09 and 3.76.

There was no difference in wear rates. The oils were tested at all RPMs and Loads, no difference between oil grades were noted. All the oils had increasing wear rates as the load increased but all increased at the same rate across the board.


I've got to see that paper in full print. There just has to be some hole in that somewhere.

Got a doc #?? They'll lose me in the geek speak text structure, but I should be able to get a good grip on test conditions.

 

[Zaedock]

Originally Posted By: gingrasr
Someone recently recommended using 15w40 for the summer due to its age and mileage.
Is this valid advice? Worth following?

Richard, if your Honda is using oil with it's current viscosity, going up a step may help out. Otherwise, just keep doing what your doing. A 15W40 would run fine, although you may see a mileage penalty in short trips.


Originally Posted By: glennc
I would say not. A 15w40 is too heavy when cold, even in summer.


No offense, but I think a ba-zillion diesel engines would disagree. My '83 C10 6.2L has about 1/2 million miles on 15w40.
I have run 15w40 in my Jeeps and tried it in my Mom's Rio. She has about a 110 mile round trip between two jobs(@ 70 yrs old

) and she hasn't seen a mileage change. I also perform OCI's of 8000+ miles on her car in summer, which is cake for fleet oil in a 1.5L gas engine.

I realize thin is in, but people don't have to be afraid of 15W40.

 

[Bambam]

15w40 has it's place and in a diesel engine it's a no brainer. Running a 40wt in a four banfger Honda or any car to combat oil useage is not a very sound piece of advise,nor is recommending a 10wXX over a 5wxx IMHO. For the xx minute warm-up what benefit is there to a 10w over a 5w,none and it has no bearing after the engine is warm right??? Oils shear but it's the hot visc we should worry about,not the cold visc.???

 

[Zaedock]

Originally Posted By: Bambam
Running a 40wt in a four banfger Honda or any car to combat oil useage is not a very sound piece of advise,


Well, that's your opinion. What would be your sound piece of advice to someone with an engine that burns 5/10W30?

Many people in many other countries run thicker than 15W40 in Honda engines and have done so for many years. There is nothing wrong with 15W40 for summer in a gas engine.

 

[Bambam]

Originally Posted By: Zaedock
Originally Posted By: Bambam
Running a 40wt in a four banfger Honda or any car to combat oil useage is not a very sound piece of advise,


Well, that's your opinion. What would be your sound piece of advice to someone with an engine that burns 5/10W30? Hence why I added IMHO.. If it burns it burns,running a heavier weight to combat ring blow-by is a snowball chance in he double hockey stick! Hard to make up that gap. Heck my cousin ran a 60wt in his old C-10 pick-up and it still smoked like a chimney. Again it's hard to fix wear with a film of oil.

Many people in many other countries run thicker than 15W40 in Honda engines and have done so for many years. There is nothing wrong with 15W40 for summer in a gas engine.


I'm sure they do but to what benefit??

 

[Zaedock]

Originally Posted By: Bambam
Originally Posted By: Zaedock
Originally Posted By: Bambam
Running a 40wt in a four banfger Honda or any car to combat oil useage is not a very sound piece of advise,


Well, that's your opinion. What would be your sound piece of advice to someone with an engine that burns 5/10W30? Hence why I added IMHO.. If it burns it burns,running a heavier weight to combat ring blow-by is a snowball chance in he double hockey stick! Hard to make up that gap. Heck my cousin ran a 60wt in his old C-10 pick-up and it still smoked like a chimney. Again it's hard to fix wear with a film of oil.

Many people in many other countries run thicker than 15W40 in Honda engines and have done so for many years. There is nothing wrong with 15W40 for summer in a gas engine.


I'm sure they do but to what benefit??


Running a 40wt isn't sound advice, but switching to a thicker HM oil is?
Right...

Your cousin's C10 smoked on 60wt, therefore running thicker oil is no good in ALL cases of oil burning. Sounds logical to me.

You have every right to think what you want, but the bottom line is that 15W40 will not harm his Honda engine if he uses it in the summer.

Richard, sorry for the slight thread hyjack. Take care.

 

[D-Roc]

Originally Posted By: Zaedock
Originally Posted By: gingrasr
Someone recently recommended using 15w40 for the summer due to its age and mileage.
Is this valid advice? Worth following?

Richard, if your Honda is using oil with it's current viscosity, going up a step may help out. Otherwise, just keep doing what your doing. A 15W40 would run fine, although you may see a mileage penalty in short trips.


Originally Posted By: glennc
I would say not. A 15w40 is too heavy when cold, even in summer.


No offense, but I think a ba-zillion diesel engines would disagree. My '83 C10 6.2L has about 1/2 million miles on 15w40.
I have run 15w40 in my Jeeps and tried it in my Mom's Rio. She has about a 110 mile round trip between two jobs(@ 70 yrs old

) and she hasn't seen a mileage change. I also perform OCI's of 8000+ miles on her car in summer, which is cake for fleet oil in a 1.5L gas engine.

I realize thin is in, but people don't have to be afraid of 15W40.



Agreed and x2...I haven't seen any reduction in wear with 5W40 as opposed to 15W40- even up here in Edmonton, Alberta in the winter.

 

[gingrasr]

Again thank you all.
I am out of my league here as I have very little knowledge about these topics.
Just needed to know if it would be safe to use the 15W40 in the Honda in the summer (it only has 191,000 not 291,000 typo error).
It normally uses 5w30.
It seems I've opened a discussion on various opposing opinions, but that's good.
Richard

 

[Bambam]

Originally Posted By: Zaedock
Originally Posted By: Bambam
Originally Posted By: Zaedock
Originally Posted By: Bambam
Running a 40wt in a four banfger Honda or any car to combat oil useage is not a very sound piece of advise,


Well, that's your opinion. What would be your sound piece of advice to someone with an engine that burns 5/10W30? Hence why I added IMHO.. If it burns it burns,running a heavier weight to combat ring blow-by is a snowball chance in he double hockey stick! Hard to make up that gap. Heck my cousin ran a 60wt in his old C-10 pick-up and it still smoked like a chimney. Again it's hard to fix wear with a film of oil.

Many people in many other countries run thicker than 15W40 in Honda engines and have done so for many years. There is nothing wrong with 15W40 for summer in a gas engine.


I'm sure they do but to what benefit??


Running a 40wt isn't sound advice, but switching to a thicker HM oil is?
Right...
When did I recommend a HM oil??? I reread his original post. He claims it has high mileage but doesn't leak or burn,SO what would be the logical reason to run an HDEO,when 5w30 is spec'd ???
Your cousin's C10 smoked on 60wt, therefore running thicker oil is no good in ALL cases of oil burning. Sounds logical to me.

Just using an example.
You have every right to think what you want, but the bottom line is that 15W40 will not harm his Honda engine if he uses it in the summer.
Maybe,maybe not? What are the benefits if no problems are indicated?
Richard, sorry for the slight thread hyjack. Take care. I too apologize for the hi-jack.

 

[glennc]

Originally Posted By: Zaedock
No offense, but I think a ba-zillion diesel engines would disagree. My '83 C10 6.2L has about 1/2 million miles on 15w40.
I have run 15w40 in my Jeeps and tried it in my Mom's Rio. She has about a 110 mile round trip between two jobs(@ 70 yrs old

) and she hasn't seen a mileage change. I also perform OCI's of 8000+ miles on her car in summer, which is cake for fleet oil in a 1.5L gas engine.

I realize thin is in, but people don't have to be afraid of 15W40.

No offense taken, of course. I run 15w40 HDEOs in all my motorcycles and have run it for nearly 100k miles in my car, which is an older BMW spec'd for heavier oils. I wouldn't run it in an engine designed for 5w30, though. I'm not saying it would lead to excessive wear or a big change in economy, but today's PCMOs are such good oils that they will give protection every bit as good as an HDEO when warm, along with better characteristics during warm-up. 15w40 is a big step up from 5w30, and my own opinion is that it is too big a jump for somebody looking for the optimal solution.

I would still suggest that a small increase in viscosity with a high mileage oil might be helpful, and if the engine is worn so much that it needs more than that, which is unlikely if it's been taken care of, there is still the intermediate possibility of switching to a "light" 40wt, maybe a 5W- or 10W-, that will give thicker oil films when warm without being unnecessarily thick when cold.

I'm not disagreeing with you when you say a 15w40 would probably give perfectly decent results, but the question is whether it's a good idea, and in my opinion the answer is no, not really.

 

[Rock_Hudstone]

Originally Posted By: glennc
I wouldn't run it in an engine designed for 5w30, though.

How exactly is an engine designed for 5w30 oil??
Are clearances so impossibly tight that only a light weight oil can sqeeze through?

I can understand arguments for cold flow properties or improved fuel economy, etc., but the push for thin oils began long ago to help auto makers meet their CAFE requirements, not because it was in the best interests of engine longevity per se.
Watch for them to spec 0-xx weight oils when the new CAFE rules kick in during the coming years.

 

[glennc]

Originally Posted By: Rock_Hudstone
How exactly is an engine designed for 5w30 oil??

For starters, it will have bearing loads suitable for the film strength of a 5w30. It will have an oil pump designed to pump 5w30 and clearances such that 5w30 will maintain appropriate flow and pressure throughout the system. Those things seem obvious and I imagine there would be some non-obvious answers as well.

Originally Posted By: Rock_Hudstone
I can understand arguments for cold flow properties or improved fuel economy, etc., but the push for thin oils began long ago to help auto makers meet their CAFE requirements.

What's wrong with that? If the engine is designed to be well protected by 5w30 oil, it probably will be. We see stellar UOA results all the time from high mileage engines using 5w30 SM oils: they do an excellent job and have plenty of reserve, apparently, to deal with difficult driving conditions, high temps, appropriate towing, etc.

The question is not, can a 15w40 be used: it is would a 15w40 be a better choice. Considering that there are definite disadvantages to using a heavier oil than necessary (more time in bypass, more warm-up wear, more friction and heat, less efficiency), I think what I've said makes good sense.