Synthetic oil ? ?
Senior Member
Joined: Nov 2011
Posts: 667
Likes: 1
From: shelley, idaho
Year: 1988
Model: Cherokee
Engine: 242CID I-6
Originally Posted by rrich
But again --- QUALITY is important.
Jeep oil filters are often on their side or upside down. The anti-drainback valve in El Cheapo filters often leak causing oil starvation on a cold start.
Jeep oil filters are often on their side or upside down. The anti-drainback valve in El Cheapo filters often leak causing oil starvation on a cold start.
CF Veteran
Joined: Apr 2012
Posts: 5,302
Likes: 23
From: Wisconsin
Model: Cherokee
Those are the primary reasons oil needs to be changed, nothing about a synthetic changes those things.
I don't think there is anything evil about synthetics- they work fine, but if you're going to change the oil every 3K regardless (see above comments on contamination), the primary "advantage" of synthetics goes away. (longer OCI)
Last edited by Radi; Jun 7, 2012 at 12:20 AM. Reason: Fixed a horrible run-on sentence.
Junior Member
Joined: Apr 2012
Posts: 55
Likes: 0
From: Fullerton/Anaheim
Year: 1989
Model: Cherokee
Engine: 4.0 L
Fake oil's molecules are all the same size - dino oil's molecules are all kinds of sizes. The larger molecules in dino oil tend to plug small leaks better.
The hype is fake oil withstands a higher temperature before it breaks down - true. But hey Buddy, if your engine gets hot enough internally to break down real oil you have major problems anyway - it's dead!
One of the reasons we use oil in the first place is it carries heat away from the hottest parts - bearings etc. 50% of the engine cooling is done by the oil. (Read about oil coolers.)
Fake oil doesn't carry away heat as easily as real oil - parts will run hotter. People like Currie - who make the best diff gears - their warranty is voided if you use syns.
The hype is fake oil needn't be changed as often. The reason we change oil is to get rid of the contaminants from combustion. Nothing stops the burning process from producing carbon particles, water, and acids in the crankcase - unless it prevents your engine from running at all.
But - mfgrs, suppliers etc all love it - it's a very high profit item.
Drive through Texas - see all those little buildings that disappear when you look right at them? Synthetic oil wells.
Synthetic - fake truth.
Avoid oils that use gimmicks to make you think they are special - ie: Adding food coloring to oil does nothing.
Quality Oils designed for automotive use already have all the additives needed to keep it slippery and working properly. Dumping snake oils in only dilutes and can counteract the lubrication properties.
If those snake oils were beneficial, don't you think the oil companies would add them and brag about it?
OIL DESIGNED FOR YOUR JAPANESE CAR - 10-30 WITH TERRIYAKI!
FOR YOUR FERRARI - 20-40 WITH OLIVE OIL
30 WT WITH KROUT!
KimChi 20 WT
MERLOT 40?
For the younger crowd - 10WT with "Nestlies Quick!"
Use quality oil with a quality filter, change them frequently.
Remember paper and the internet don't reject words - lies and hype look real.
The hype is fake oil withstands a higher temperature before it breaks down - true. But hey Buddy, if your engine gets hot enough internally to break down real oil you have major problems anyway - it's dead!
One of the reasons we use oil in the first place is it carries heat away from the hottest parts - bearings etc. 50% of the engine cooling is done by the oil. (Read about oil coolers.)
Fake oil doesn't carry away heat as easily as real oil - parts will run hotter. People like Currie - who make the best diff gears - their warranty is voided if you use syns.
The hype is fake oil needn't be changed as often. The reason we change oil is to get rid of the contaminants from combustion. Nothing stops the burning process from producing carbon particles, water, and acids in the crankcase - unless it prevents your engine from running at all.
But - mfgrs, suppliers etc all love it - it's a very high profit item.
Drive through Texas - see all those little buildings that disappear when you look right at them? Synthetic oil wells.
Synthetic - fake truth.
Avoid oils that use gimmicks to make you think they are special - ie: Adding food coloring to oil does nothing.
Quality Oils designed for automotive use already have all the additives needed to keep it slippery and working properly. Dumping snake oils in only dilutes and can counteract the lubrication properties.
If those snake oils were beneficial, don't you think the oil companies would add them and brag about it?
OIL DESIGNED FOR YOUR JAPANESE CAR - 10-30 WITH TERRIYAKI!
FOR YOUR FERRARI - 20-40 WITH OLIVE OIL
30 WT WITH KROUT!
KimChi 20 WT
MERLOT 40?
For the younger crowd - 10WT with "Nestlies Quick!"
Use quality oil with a quality filter, change them frequently.
Remember paper and the internet don't reject words - lies and hype look real.
Senior Member
Joined: Jan 2012
Posts: 648
Likes: 1
From: Port Richey, FL
Model: Cherokee
Engine: 4.0
Personally, I use Shell Rotella or Delvac. Whichever's cheaper at the moment. Diesel oil won't let you down. I run it in my cars, trucks, and V-twin motorcycles.
Herp Derp Jerp
Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
Some manufacturers these days actually do call for synthetic lubricants. FWIW, not all synthetics are actually 'man-made': A lot of the popular brands are highly refined base oils, which achieve a similar effect in even molecule size.
If you want to do real reading visit www.bobistheoilguy.com and check out Used Oil Analyses performed by independent labs.
This. The 4.0 is specced for the heavier weights found in diesel oils in foreign markets. They're designed for a longer service life than gasoline oils and still have ingredients that our ancient engines expect. Even if you change your oil at the same intervals, if your engine is worn you will still benefit from greater soot control and detergents. Just don't dump 15W40 in a Honda that calls for 0W20 lol
If you want to do real reading visit www.bobistheoilguy.com and check out Used Oil Analyses performed by independent labs.
Originally Posted by kickice24
Personally, I use Shell Rotella or Delvac. Whichever's cheaper at the moment. Diesel oil won't let you down. I run it in my cars, trucks, and V-twin motorcycles.
Senior Member
Joined: Jan 2012
Posts: 648
Likes: 1
From: Port Richey, FL
Model: Cherokee
Engine: 4.0
I don't usually worry about it because I live in FL where it's warm enough to run my Rotella. I could see in a colder climate where it might not be as favorable. 
Senior Member
Joined: Jan 2012
Posts: 648
Likes: 1
From: Port Richey, FL
Model: Cherokee
Engine: 4.0
I don't consider 15w-40 that heavy. I ran Castrol 20w-50 in my VW's for years until I switched to Rotella. Never had an engine related failure in my life. Now transmissions...
Member
Joined: Jun 2012
Posts: 200
Likes: 0
From: Colorado Springs Colorado
Year: 96
Model: Cherokee
Engine: 4.0
I was of the understanding that a significant portion of the carbon particles and other items that built up are there because of the traditional oil (which contains hydrocarbons) coating the cylinder walls getting burned and going through a reactive process. The idea being that synth oils don't react as much, and therefore reduce the amount of those substances that build up in the first place.
I'm not saying the aren't some carbon particles being blown up peoples' behinds by the synth manufacturers, but there seems to be enough objective study and science behind it to show that there is some benefit.
I'm not saying the aren't some carbon particles being blown up peoples' behinds by the synth manufacturers, but there seems to be enough objective study and science behind it to show that there is some benefit.
Correct me if Im wrong but I believe deposits are burned parafin wax. Does synthetic use parafin?
