Dino every 5k or syn every 7.5k? (consumer math!)

[Zaedock]

I don't understand the fixed 5K and 7.5K values. How did you determine that conventional should be changed at 5K miles?

My wife's old Malibu Maxx, which my daughter now drives, has 170,000 miles and has had nothing but conventional changed at the OLM. Most of the oil used was Supertech 5W30! UOA's confirmed the 6,XXX or 7,XXX mile intervals (depending on winter/summer respectively) and I posted a picture of inside the head last year which was shiny clean.

I recommend spending some change on a UOA to help determine a more accurate number.

 

[ATex7239]

Whatever is cheapest at the time.

 

[shurguywutt]

I run synthetic for 7k-10k. I have run M1 syn 5w30, Valvoline syn 5w30, RP 5w20, and now I am on RLO 0w20. I have not noticed any difference with consumption. Still use about a qt every 4-5k. Does not matter if it is cheap syn or expensive syn, 5w30 or 0w20. With this being said, I am going to try the Valvoline HM syn 5w20 for my next change to see if I get different results. I am also going to start changing my filter (RP) every other change. I think when your engine consumes oil, expensive oil is just not worth it because if you are replacing oil you are refreshing the additive pack anyway.

 

[FordBroncoVWJeta]

Originally Posted By: Gebo
Something is wrong with me. I love changing oil as much as I like having sex. And I really like having sex with my wife.
IBTL

 

[i_hate_autofraud]

After doing this for the last few years, if you use dino or syn, you can go fairly
long, 7,500 –10,000 miles is easy and most UOA on a healthy engine will show oil is
still usable with a Total Base Number (TBN) of 2.0 to 4.5, easy. A TBN of 1.0 is the
‘must replace’ point.

Having swapped all kinds of filters, oils, the one thing that keeps my oil cleaner
longer is in this PDF, good pics too. I wish I thought of it as a kid when I drove
from coast to coast on a regular basis!


“ FILTERMAG vs HOMEBREW “
https://app.box.com/s/uxvu8dmscf5wcgftutdm0ejqwgn86tw7

 

[dmack2]

TmanP,
Check your math.

 

[Gebo]

Originally Posted By: ATex7239
Originally Posted By: Gebo
Something is wrong with me. I love changing oil as much as I like having sex. And I really like having sex with my wife.


Then you're doing it wrong...


I YouTube'd it. I've been doing it this way for over 33 years.

 

[oldmaninsc]

Originally Posted By: dmack2
TmanP,
Check your math.


Originally Posted By: TmanP
Example:
MS5k for $14.44, and a filter (ACDelco for my application) for $4.29= $18.73. If you run this combination for 5,000 miles, it comes out to .37 cents per mile.


I noticed that also. If it was .37 per mile, then times 5,000 miles equals $1,850.00 That is one expensive oil change!

 

[wemay]

If not Direct Injection, choosing a top brand 'conventional' would suffice at either OCI. Most are now syn blends anyway. Check their websites.

 

[BrocLuno]

Originally Posted By: oldmaninsc
Originally Posted By: dmack2
TmanP,
Check your math.


Originally Posted By: TmanP
Example:
MS5k for $14.44, and a filter (ACDelco for my application) for $4.29= $18.73. If you run this combination for 5,000 miles, it comes out to .37 cents per mile.


I noticed that also. If it was .37 per mile, then times 5,000 miles equals $1,850.00 That is one expensive oil change!

Yeah, the math is a bit off

$0.00~4 (four tenths of a cent)per mile is about where it comes out to me ... Since it is prolly below tire wear cost, I don't really care about a few 1/10ths of a cent one way or another. Not when gasoline is anywhere from $0.10 to $0.45 a gallon different within a week and two town apart. I can save the difference in the oil change cost by filling up anywhere it's under $3

 

[CR94]

Originally Posted By: oldmaninsc
Originally Posted By: dmack2
TmanP,
Check your math.


Originally Posted By: TmanP
Example:
MS5k for $14.44, and a filter (ACDelco for my application) for $4.29= $18.73. If you run this combination for 5,000 miles, it comes out to .37 cents per mile.


I noticed that also. If it was .37 per mile, then times 5,000 miles equals $1,850.00 That is one expensive oil change!

No, TmanP's math was right. Check yours.

 

[JohnnyJohnson]

Originally Posted By: CR94
Originally Posted By: oldmaninsc
Originally Posted By: dmack2
TmanP,
Check your math.


Originally Posted By: TmanP
Example:
MS5k for $14.44, and a filter (ACDelco for my application) for $4.29= $18.73. If you run this combination for 5,000 miles, it comes out to .37 cents per mile.


I noticed that also. If it was .37 per mile, then times 5,000 miles equals $1,850.00 That is one expensive oil change!

No, TmanP's math was right. Check yours.


No 18.73 divided by 5000 gives you cents per mile. Which is .003746 cents per mile. You couldn't afford to operate a car on your math.

 

[SR5]

Quote:
Example:
MS5k for $14.44, and a filter (ACDelco for my application) for $4.29= $18.73. If you run this combination for 5,000 miles, it comes out to .37 cents per mile.

PP for $22.97 and a filter for $4.29 = $27.26. This oil must be run for 7,502 miles to break even (at that same cost of .37 cents per mile).


Good question OP, sure you may find better deals for either, and sure you can look at extending the OCI for either, but the fundamental question is valid.

By your calculations the two are economically equivalent, and I would say mechanically equivalent too.

So the fundamental question is a lifestyle one. If you have the time and enjoy changing oil, then go the Dino. If you are time poor then go the synthetic at longer OCI.

Right now fairly busy and so I have M1 5W30 in the sump, my plan was to change the oil at 6 to 7.5 k miles, but if I get busy, then I can relax and extend the OCI up to 10k miles.

 

[TmanP]

Nope, it's correct. Notice the decimal point. I said .37 cents per mile- that means 37/100 of a cent per mile, not 37 cents per mile. (I wrote .37 cents, not $0.37, which is 37 cents.)

(I see where you're coming from, though.) To make the math easier, round to $20 every 5k. That's $1 every 250 miles, or 4/10 of a cent per mile.

Anyway, that's inconsequential. Thanks for everyone's responses!

 

[TiredTrucker]

And folks will quibble over fractions of cents per mile for an oil change, and break it all down to strain at every little bit of life out of an oil, but will drop a wad of dollars on just a Saturday night out at a restaurant without even giving it a thought. Amazing how some folk's minds work.

 

[CR94]

Originally Posted By: TmanP
... (I wrote .37 cents, not $0.37, which is 37 cents.) ...
That's correct, although 0.37 cents might've been slightly more clear---which might or might not have helped the people who are apparently arithmetically challenged.

 

[ArcticDriver]

Originally Posted By: CR94
Originally Posted By: TmanP
... (I wrote .37 cents, not $0.37, which is 37 cents.) ...
That's correct, although 0.37 cents might've been slightly more clear---which might or might not have helped the people who are apparently arithmetically ckhallenged.


I find the people who must argue such trivial matters as this to be no different from those who comment on misspellings (aka, "selling nazis"). In both cases, the intention of the writer is still obvious and his meaning understood.

 

[marine65]

I use full synthetic in both of my cars.
Here in Colorado the temperature can be from 100F to minus 30F.
I'm not saying conventional oil cant handle this but I just feel better with full synthetic regardless of cost.

 

[BISCUT]

Originally Posted By: turnbowm
I was doing 5Kmi OCIs with conventional oil, but decided to do extended (7.%Kmi) changes with synthetic. The less time I spend under a car the better.


What is not factored into the OP's equation is the value of time. 5k ='s more time spent changing oil over 7.5k. Time is valuable; once it's gone you cant get it back.

 

[ZZman]

Syn as I am anal about using it. But also included is the hassle factor savings. One less oil change to do a year.