Synthetic, Blend, or Conventional Oil?

UnoBurro

Member
Apr 28, 2018
57
South/Southwest
When I bought my Jeep new in 2001 I used Castrol full synthetic and it would seep ever so slightly around the rear main seal. Maybe a drop or two would sometimes hit the pavement over time but it wasn't much. Later I switched to a synthetic blend high mileage oil (Castrol or Valvoline) and the slight seepage pretty much stopped with virtually no drips.
 
OP
rasband

rasband

LJR Junkie
Supporting Member
Sep 11, 2018
533
Denver, CO
Nope. Just change your oil and filter and go.
It’s generally safe to go from Synthetic to Conventional as Mr. Bills said.

However for those thinking about going the opposite direction (conventional to synthetic), it can be problematic and should be done in phases (conventional -> blend -> synthetic). The reason being seals can be worn and synthetic can start leaking where conventional didn’t before. A few folks have alluded to this above as well.
 

Jerry Bransford

TJ Guru
Supporting Member
Nov 9, 2015
9,972
Escondido California
Not sure of the brand but the bigger one is what I used the first time I changed my TJ oil.
The TG in TG16 and TG8A stands for Tough Guard made by Fram. The Tough Guard is a very good oil filter with a 99% filtration efficiency. Some far more expensive oil filters only have a 95% filtration efficiency. That percentage is how much of a certified micron size of a lab test 'dirt' gets filtered out by the filter.
 

skrelnik

TJ Enthusiast
Supporting Member
Jan 10, 2018
877
CT, United States
So we know what some from the warmer climates prefer, where are the colder climates at? Last post I saw was the filter rec, what oil do you like? Earlier:

What's everyone using for oil filters . . . . ? (4.0L inline 6)
Wix 51085XP or 51085
Up here in New England I use Pennzoil 10w-30 high mileage full synthetic, but during the winter I put in Pennzoil 5w-30 high mileage full synthetic.

Since I change my oil every 6 months, about 4k miles each change, I can find a great sale on a 5 quart jug for like $22. Sometimes Advance Auto will sell a jug and Boss Puralator filter for $30. I will use another high mileage full synthetic if there is a sale, like Castrol, but generally I stick to Pennzoil.

For filters I use Boss purolator PBL14670 or PL14670, whichever one Advance Auto includes in the sale. If not that Purolator then Mopar OEM.
 

Willys LJ

TJ Enthusiast
Oct 26, 2018
184
Dyer TN
Thanks for the heads up on the larger oil filter. I was wondering if there was one. The auto manufacturers going to small filters never made any sense to me other than saving them a little money in the manufacture of the car.

I haven't had my LJ long enough for an oil change, I figure I'll use the same 10w40 fleet oil that I use in my old tractor.
 

Jerry Bransford

TJ Guru
Supporting Member
Nov 9, 2015
9,972
Escondido California
Thanks for the heads up on the larger oil filter. I was wondering if there was one. The auto manufacturers going to small filters never made any sense to me other than saving them a little money in the manufacture of the car.

I haven't had my LJ long enough for an oil change, I figure I'll use the same 10w40 fleet oil that I use in my old tractor.
10W-30 is recommended.
 
Reactions: skrelnik

skrelnik

TJ Enthusiast
Supporting Member
Jan 10, 2018
877
CT, United States
Mobile 1 Full Synthetic 10W-30 and a Wix Filter.
Advance Auto usually has a good promo for name brand oils. Now they have, for $33, a 5qt jug of Mobil full synthetic (or full synthetic high mileage), plus a Purolator Boss filter and a free hat.

https://shop.advanceautoparts.com/o/oil-change-specials

I usually hop on these specials, and so far my kid has a Castrol Need for Speed hat and a pair of Hoonigan socks.
 
Reactions: mikespine

pagrey

TJ Enthusiast
Apr 10, 2018
233
Los Angeles, CA, USA
I'm in the distillation business, and I can assure you that synthetic being superior isn't a marketing pitch. It's a completely different refining process than conventional oils that remove all impurities. I'm not saying at all that conventional oil is bad or will cause problems for your engine, but synthetic is indeed better, and for the couple of extra bucks it cost, i'm always going to buy it.
Did you read the Blackstone test data that says synthetic isn't indeed better? Why would anybody listen to you, who are you, where is your data?
 

pagrey

TJ Enthusiast
Apr 10, 2018
233
Los Angeles, CA, USA
I was just about to unsubscribe. Now I'm grabbing the popcorn. :)
Oil discussions are great, although people often have strong opinions on the subject I think it helps, especially for somebody that isn't a die-hard brand loyalest to re-think their habits every once and awhile. Filters are also interesting, the MO-090 from Chrysler has a different bypass valve assembly with the spring integral to the threaded filter mount. The only other filter available with this design is the FL-300 (short FL-1A) from Motorcraft. For those that run other filters like Fram, Mobil 1, Napa Gold or just about anything else, you aren't really getting what Chrysler intended. The Chrysler filters are just $7 at Walmart and the FL-300 is under $4 at rockauto. Next time you buy a filter take a look at the threaded end and you'll see, it is obvious.
 

Alex0413

TJ Enthusiast
Oct 26, 2018
122
Baton Rouge, LA
Did you read the Blackstone test data that says synthetic isn't indeed better? Why would anybody listen to you, who are you, where is your data?
**TRIGGERED** LOL

Do you normally form your opinions and beliefs off of one report?

Sure did read it, a small sample of daily driven cars isn't that compelling to me, especially since it's not over a long period of time. Using a different oil each oil change, doesn't exactly follow the scientific method, does it? I don't expect one oil change of synthetic oil to magically make a difference in engine wear over a 4000mi sample. When you have an engine being abused in extreme conditions (offroading), high performance oil does indeed help. If you understand the differences in conventional and synthetic oil, you understand that synthetic is superior in every way (except the slight price difference).

I do recommend you read through all of these chapters if you would like some data:

https://www.bobistheoilguy.com/motor-oil-101/
 

Mr. Bills

TJ Addict
Nov 24, 2017
1,159
Area Code 530
. . . I do recommend you read through all of these chapters if you would like some data: https://www.bobistheoilguy.com/motor-oil-101/
Excerpts from your link:

"[Synthetic oils] are also more expensive and might be overkill for the average person driving to and from work, getting groceries and taking the kids to soccer practice and school."

". . . [A] synthetic oil can run longer oil drain intervals, in more harsh conditions than their mineral oil counterparts. . . . For some people this is an important factor, for others it might be overkill. Whatever you choose – make sure you follow your owner’s manual recommendation and match the type of oil you buy to the oil drain interval you follow." [Emphasis supplied.]

"You do not have to use synthetic oil, but there can be some real advantages to doing so. There are lots of people who use synthetic, just like there are a lot of people who do not."

The first and third excerpts acknowledge that synthetic motor oil isn't appropriate for everyone and every situation. The second demonstrates why synthetic motor oil isn't necessarily the best choice for a jeep engine.

The drain interval recommended by the Chrysler for Schedule B "severe duty" use is 3,000 miles. For light duty use the recommended service interval is 6,000 miles. If one follows BOBistheOilGuy's advice and matches the type of oil to the factory recommended service interval, the best match will not be full synthetic motor oil for most jeepers in most climates. Instead, the best type match will often be conventional motor oil for Schedule B and either conventional or a synthetic blend for Schedule A.

There are many valid reasons for choosing synthetic motor oil. A blanket statement that synthetics are "superior in every way" isn't one of them. Apparently neither is a non-specific citation to BOBistheOilGuy. However, BOBistheOilGuy does offer sound advice when he writes at the end of Motor Oil 101, Chapter 4:

"If you are looking for a good oil to use first check your owner’s manual, then make sure you pick the right viscosity grade and do not be afraid to choose something that has better cold temperature performance because that will help with better startup and reduced energy consumption. Learn about the different specifications and applications oils are designed for, then pick a brand that makes you comfortable. "
 

Jerry Bransford

TJ Guru
Supporting Member
Nov 9, 2015
9,972
Escondido California
**TRIGGERED** LOL

Do you normally form your opinions and beliefs off of one report?

Sure did read it, a small sample of daily driven cars isn't that compelling to me, especially since it's not over a long period of time. Using a different oil each oil change, doesn't exactly follow the scientific method, does it? I don't expect one oil change of synthetic oil to magically make a difference in engine wear over a 4000mi sample. When you have an engine being abused in extreme conditions (offroading), high performance oil does indeed help. If you understand the differences in conventional and synthetic oil, you understand that synthetic is superior in every way (except the slight price difference).

I do recommend you read through all of these chapters if you would like some data:

https://www.bobistheoilguy.com/motor-oil-101/
What benefit do you claim synthetic oil would have given me over my 55 years of driving with nothing but conventional motor oils with absolutely never an engine issue? The only thing I ever did was change the oil and filter at appropriate intervals. And nearly all were driven well into the six figures before selling them aside from my previous TJ that was stolen ten years ago with approx 198k miles on it.

Not to mention the old ads from Volvo and Mercedes showing their engines making it to over one million miles... in the days before synthetic oils were readily available on the store shelves.

To read the opinions of some synthetic oil enthusiasts our engines don't stand a chance of making it to 50-100k miles without using a synthetic oil. :risas3:
 
Reactions: Chris