Does using "Thicker" Oil Make Engines last Longer?

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.. "Thicker" =

1) xW-40 *0W-40 and.or 5W-40 Full Synth, 10W-40 Blend, or 15W-40

2) 15W-50 Full Synth

I have noticed that those that have used "xW-40" Oils.. Conventional, Diesel, Blend, Old, New, Whatever...

.. Have cars that last 200,000 miles or more...

.. Much like my parents 1982 Oldsmobile DELTA 88 Royale Brougham with the 302... Over 350,000 miles, ran for CONSIDERABLE time after that...

.. and i Know its Oversimplification and they tend to be V8s or V6s that report the long lasting.. but IS there a connection where 40 beats out 30 in this Department?

OR can it last -exactly the same- on a nice 5W-30?

You all know my car.. Im asking more in terms of Engine Health and the "Heavier" Oil, assuming it doesnt get too cold.

My understanding is that if the Thicker film does NOT Shear or Foam, ait will provide the moving parts a thicker Cushion.. is it really that simple?

I also seem to recall EVERY Car with an Oil Pressure Gauge (1991-1994 Blazers S-10, the Delta 88, etc) always showed LOWER Pressure with 10W-40. Thicker Oil.. Less Pressurization, due to more Space taken up by the Film, yes?

- JC
 
I also seem to recall reading that Mobil 1 15W-50 provided 70% Better "Actual Lubrication" than Conventional 20W-50. makes sense, if the Conventional 20W-50 was blowing apart, i can see that...
 
No. Use what the mfg specs! There are plenty of engines running on thinner oils lasting well over 300,000 miles too. Save the thicker oils for when the car starts leaking or burning oil.
 
Look at all the taxis that have run on bulk 5w20 for well over 200k. I would be willing to bet that there are more longer lasting engines these days with the modern lighter weight oils. The technology is getting batter every day.
 
Originally Posted By: demarpaint
No. Use what the mfg specs! There are plenty of engines running on thinner oils lasting well over 300,000 miles too. Save the thicker oils for when the car starts leaking or burning oil.


+1
 
Originally Posted By: daves87rs
Originally Posted By: demarpaint
No. Use what the mfg specs! There are plenty of engines running on thinner oils lasting well over 300,000 miles too. Save the thicker oils for when the car starts leaking or burning oil.


+1


So.. it can literally go either way, with Lighter OR Heavier oils making them last longer? OR using same grade for the life?

Seems "Hot Summer Days" are NOT a good reason to switch from 5W-30 to 10W-30?

i was just posing the question.
 
Originally Posted By: JCCADILLACMOBILE

Seems "Hot Summer Days" are NOT a good reason to switch from 5W-30 to 10W-30?

i was just posing the question.


Hot summer days is just a typical excuse for southerners to go to 15W50 or 20W50 on their Honda engines(which now calls for 5W20/5W20), with excuses such as "I'll be idling in Austin,TX. downtown traffic for ieons, with A/C on full blast, or I'll be driving in-n-out of death valley in my car while playing hide-n-seek,etc."

Play it safe: you can't go wrong with factory recommended specs.


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Last edited:
Originally Posted By: demarpaint
No. Use what the mfg specs! There are plenty of engines running on thinner oils lasting well over 300,000 miles too. Save the thicker oils for when the car starts leaking or burning oil.


Agree!

394,000 miles on a high rev 4 cyl using 10w-30 until 5w-30 became main stream.

A drunk took the car out, not the oil type or weight.

Bill
 
You're trading flow for pressure with that thick oil, you know...

I would say no, if asked to make a generalization.

I've always used x-30 on everything with 4 wheels. 187,000, 213,000, 111,000 were the mileage on the last three cars I've moved on from.
 
Originally Posted By: Bill in Utah
Originally Posted By: demarpaint
No. Use what the mfg specs! There are plenty of engines running on thinner oils lasting well over 300,000 miles too. Save the thicker oils for when the car starts leaking or burning oil.


Agree!

394,000 miles on a high rev 4 cyl using 10w-30 until 5w-30 became main stream.

A drunk took the car out, not the oil type or weight.

Bill


Also to Bepperb: So basically, to discredit the Southerners and all.. the Needs of th Engine do NOT change with Mileage (Thicker Oil)?
 
Originally Posted By: Bill in Utah
Originally Posted By: demarpaint
No. Use what the mfg specs! There are plenty of engines running on thinner oils lasting well over 300,000 miles too. Save the thicker oils for when the car starts leaking or burning oil.


Agree!

394,000 miles on a high rev 4 cyl using 10w-30 until 5w-30 became main stream.

A drunk took the car out, not the oil type or weight.

Bill


was this with dino or synthetic?
 
Originally Posted By: Steve S
It would depend.
Could not agree more :)
Outside of this: it would be generalizitions
 
Last edited:
Originally Posted By: JCCADILLACMOBILE
Ive also heard that "No American Manufacturer has ever recommended 10W-40 for use in the car." Whereas german cars (VW, BMW) LOOOVE 10W-40 at LEAST...


I remember them recommending 10W-40 back in the late 60's and early 70's.
The reason they stopped recommending it was because of the polymer content was so high to get that viscosity spred that it caused ring sticking and oil burning.
I don't know this for a fact, but I did read something on it back then.
 
Originally Posted By: JCCADILLACMOBILE


Also to Bepperb: So basically, to discredit the Southerners and all.. the Needs of th Engine do NOT change with Mileage (Thicker Oil)?


Correct. Just because the engine has miles does not mean that you HAVE to go up on weight.

Every engine that I've taken well past 200,000 miles and once I sold the vehicle it continued to run fine have stayed with the same grade from new to present. (ie xw-30)

Originally Posted By: QMartinez
Originally Posted By: Bill in Utah

Agree!

394,000 miles on a high rev 4 cyl using 10w-30 until 5w-30 became main stream.

A drunk took the car out, not the oil type or weight.

Bill


was this with dino or synthetic?
Conventional oil. Mostly what was on sale (Valvoline and Halvoline for most part).

And that vehicle was a 1986 so a lot of the miles were on yesterdays oils.

Today's are MUCH better!
thumbsup2.gif


Bill
 
Originally Posted By: lonestar60
Originally Posted By: JCCADILLACMOBILE
Ive also heard that "No American Manufacturer has ever recommended 10W-40 for use in the car." Whereas german cars (VW, BMW) LOOOVE 10W-40 at LEAST...


I remember them recommending 10W-40 back in the late 60's and early 70's.
The reason they stopped recommending it was because of the polymer content was so high to get that viscosity spred that it caused ring sticking and oil burning.
I don't know this for a fact, but I did read something on it back then.
Yes that is so .I worked at a fleet repair shop and some engines would come in with low miles and burn oil . When you took them apart everything would look good no real wear but the oil rings would be stuck in the piston ring groves. I also wonder is the driving style had something to do with the ring sticking?
 
No, viscosity is not as important as it used to be. Modern additives have improved film strength and have allowed lower viscosity oils to be used.
 
I would say other than the bad engine that no matter what oil is run has trouble. The maintenance schedule and care is most important to engine life. A good air cleaner and seal of the intake is most important. You can put the BEST in your opinion syn oil and have no airfilter and the engine will die the same death in the same time as the running the cheapest oil you can buy.
 
Imo it just depends on the type of car and the way it`s going to be driven. In every car I`ve owned,I`ve always gotten an fsm so I can learn the car and do all the repairs/maintenence myself. They always state to use the recommended (usually 10W30) for "energy conservation" only. Then it`ll go on to say they recommend going to a thicker grade (10W40,15W40,20W40,20W50) if the car is going to be raced or driven at sustained high speeds.
 
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