Synthetic Oil ?

[scrap_iron]

Any of you out there have experience with synthetic motor oil over the long haul ?
I bought a 88 Cherokee 4wd/4.0L/Auto w/ 170k miles. I heard this motor has a good reputation for racking up the miles. However, I keep hearing about the benefits of synthetic oils, but are there any negative things I should consider (OTHER than the price)? Would it help/hurt switching an older engine to it ? Does it have any affects to seals and gaskets ? Would a small leak get worse ? Will valve seals be affected by the change? etc.

[JDPascal]

There are varying OPINIONS on all of the above questions.

I have found that leakage hasn't changed.

Oil consumption has gone up a bit still over 2000 miles per quart though.

It is an area where the cost/benefit relationship is not obvious therefore you will find a wide range of supporters and detractors.

Currently I am using Mobil 1 and have over 8K kilometers (5K miles) on the oil change with one filter change at about half way. It is important to change the filter at the regular interval and with the makup oil for normal usage and filter changes I plan on making about the 15000 Kilometers (9 - 10K miles) before I do a complete dump with a quick flush additive.

I believe this is a workable arrangement because of the makeup oil and on the next similar cycle I plan on doing an oil analysis at the 3/4 point to see what is happening.

JD

[scuba4321]

synthetic oil is better than non sythetic, you can go loner with out changing the oil, but still have to change filter than top off. The only time not to use it is with a new motor, you should wait after the break in period is up! The cost is higher, and with 6qts too! These 4.0 will go for a long time with either types of oil though!!

[Carlson327]

I would think that with so many miles on the engine, any benefit from synthetic oil is probably too late. IMHO, save your money and change standard oil according to the owner's manual.

[JDPascal]

There are benefits to using synthetic oil other than mileage related ones.

Cold weather starting is one. I'm talking below 0F like it is here today. Easier on the starter and electrical system due to easier cranking.

Cold start lube is better due to faster circulation and first lube at critical points though this is related to engine life too.

Lower spot temperatures in the engine, transmission or Diff due to a "slippryier" oil and a better additive packager will likely be found in a synthetic oil due to the high end nature of the product (imho)

Wear that has already started or progressed to a point just shy of failure obviously won't be prevented but perhaps some benefit could be realized here also.

A cost benefit consideration needs to be made as in any undertaking and also consider the overal condition of the engine and previous maintenance. If the previous owner never changed the oil or did so rather infrequently, did a lot of short trips and the engine is sludged up, then I would really think twice about it.

If you have owned it since new or soon after, maintained it well with regular oil changes and want to give your baby a treat, go for it. Watch the oil consumption and change the filter at the same interval you would with regular oil if you try extending the change interval. If you get nervous, dump it and go back to the regular dino oil and the old change schedule.

Carlson327 does have a point about the higher cost but every one has to make up their own mind about what they are willing to pay and how good it makes them feel when they spend their hard earned money. When you add it up sometimes more = less in the total picture.

I would never say that synthetic oil is for every one or every application

HAPPY NEW YEAR!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

JD

[scrap_iron]

Thanks for all feedback guys. JD, the cold start advantages are a good point and will probably sway me toward trying it. Those 10 degree (F) days are brutal on an engine. Any idea why synthetic oil it is not recommended for new engines ?
Also, what is the synth-blend ? Just from reading the package, my guess is it's reguler petro based oil with synthetic additives. It sounds similar to these high mileage oils you see on the market now - primarily more additives.

[95xjsport]

all my friends well most like that synthetic stuff. I don't believe in that crap. all my vehicles have used normal motor oil, and I have never had any oil related problems... just my .02

[JDPascal]

Originally Posted by scrap_iron

Thanks for all feedback guys. JD, the cold start advantages are a good point and will probably sway me toward trying it. Those 10 degree (F) days are brutal on an engine. Any idea why synthetic oil it is not recommended for new engines ? .

The superior lubricating ability is what keeps synthetic oil from being used in "new" engines. A newly built engine needs some initial wear to match the surfaces between moving parts like piston rings. Synthetic oil prevents a large part of this wear and results in poor performance later on. With the improvement in machining capabilities, some of this wear may no longer be necessary in higher end engines for new performance cars but at least some of these engines are run in on a dyno using a break-in oil and then the synthetic oil is added later.
This fact should tell us something about a benefit of using syntheic oil in our vehicles.

Originally Posted by scrap_iron

Also, what is the synth-blend ? Just from reading the package, my guess is it's reguler petro based oil with synthetic additives. It sounds similar to these high mileage oils you see on the market now - primarily more additives.

Synth-blend or part synthetic oils are just that ---- Some synthetic oil mixed with some "dino" oil.

The additives used in any oil are all man made or synthetic. Synthetic oils have molecules that are manufactured to be all the same size and same shape where a "normal" oil has molecules of varying sizes and shapes. The variance in molecules causes flow and lube "lapses" that are not present in a synthetic. Cold weather flow in a synthetic is better because there is no naturally ocurring parafin present unlike the dino oil where it is dewaxed and a Pour Point Depressent additive is used to reduce clumping of the remaining wax molecules as temperatures drop.

People will claim that they can't see a difference or that they've never had any oil related problems with regular oil and that is probably true. What is also true is that they have nothing to compare their wear patterns to and most people don't keep NEW vehicles long enough to encounter problems. After getting rid of the vehicle, the new owner is responsible for the repairs and many failures that are attributed to "high mileage" or other reasons could have been prevented or postponed by better lubrication maintenance - better oil and proper oil change intervals and perhaps oil analysis by a reputable lab.

Anyway ------- Anyone considering the use of synthetic oil in their vehicle should research the subject thoroughly for themselves and consider their driving patterns (short trips benefit less in some ways) and figure out what they expect to gain for the difference in price.

Hope this helps some more........

JD

[95xjsport]

Originally Posted by JDPascal

People will claim that they can't see a difference or that they've never had any oil related problems with regular oil and that is probably true. What is also true is that they have nothing to compare their wear patterns to and most people don't keep NEW vehicles long enough to encounter problems. After getting rid of the vehicle, the new owner is responsible for the repairs and many failures that are attributed to "high mileage" or other reasons could have been prevented or postponed by better lubrication maintenance - better oil and proper oil change intervals and perhaps oil analysis by a reputable lab.

My jeep has about 155000 miles and not oil related problems, I just use regular motor oil

[JDPascal]

Originally Posted by 95xjsport

My jeep has about 155000 miles and not oil related problems, I just use regular motor oil

Originally Posted by JDPascal

Carlson327 does have a point about the higher cost but every one has to make up their own mind about what they are willing to pay and how good it makes them feel when they spend their hard earned money. When you add it up sometimes more = less in the total picture.

I would never say that synthetic oil is for every one or every application

Just to clarify my position here................

If what you are doing to maintain your vehicle is working for you and you are happy with the results you are getting, continue to do it.

If you think you can get better results with other methods and materials, then research and ask questions before you jump into something.

This is no different than any other area of life. Know what you want. Find out how to get it and be prepared to pay the price for what you end up with.

JD

[tgrudzin]

I was planning on using a synthetic oil in my Jeep and my Dodge van. We tow a pop-up with both vehicles. The van consumes oil at about a quart quickly when towing. If I had synthetic in the van, and still plan on changing the oil every 3-4K, which oil should I use to top off, synthetic or dino oil?

As for the price, Costco sells it for about $23.00 a six pack. About the same price as if I would have taken my Jeep into a quickie place, or about $18.00 over the price of Pennzoil. I've wasted more money then that buying drinks for women who I have no chance at.

[JDPascal]

IMO there is no point in starting to use the synthetic if you intend to top off with dino.

Not sure what a "quart quickly" amounts to but if you are topping off at the rate of 2 or 3 quarts in 5K miles, then consider extending the OCI to 7500 miles as the top off will replace the additive used up by contamination.

You'll still have at least one of that six pack left for top up

This is a suggestion based on the fuel system, air cleaner, compression and all the other oil contaminating sources being in good shape.


Just one persons opinion.

JD

PS
2000 miles to a quart of oil is not a lot of consumption. That works out to 0.016 floz/mile driven.

[scrap_iron]

Originally Posted by JDPascal

There are benefits to using synthetic oil other than mileage related ones.

Cold weather starting is one. I'm talking below 0F like it is here today. Easier on the starter and electrical system due to easier cranking.

Cold start lube is better due to faster circulation and first lube at critical points though this is related to engine life too.

Lower spot temperatures in the engine, transmission or Diff due to a "slippryier" oil and a better additive packager will likely be found in a synthetic oil due to the high end nature of the product (imho)

Wear that has already started or progressed to a point just shy of failure obviously won't be prevented but perhaps some benefit could be realized here also.

JD

JD,
I've been running the Mobil 1, 10-30 for about 2 weeks now and I like what I am seeing. The engine runs noticably quieter and smoother even after warming up. And it does turn over more easily on cold mornings. So far so good - Thanks

[Arctic4lo]

Im in Anchorage, Alaska. At random times during the winter, I'll have to start my jeep at 0530 in the morning for work when its 20 or 30 below out. I dont have a block heater, as does most every other vehicle around here, nor do I have a warm garage to park in. Every morning like clockwork my jeep will crank for 1-2 seconds, and fire. I have been using synthetics (royal purple, mobil1, castrol syntec [mainly] among others) since the purchase of the XJ, and notice that much of the 4.0's trademark harshness, and brashness is more noticeable in the jeeps of friends who use conventional oil, as opposed to mine. Its nice being able to drive off in the morning knowing my super long cast iron, 8 year old, 70k mile straight six left the guy in the 2003 Ford Ranger next to me, with a plugged-in block heater, wondering why his truck makes a sad vocal impession of a beagle before it dies when turning the key.
I like sythetic oil.

[jtdragonrave]

I have an 88 jeep cherokee 4.0 litre and I have 163,000 miles and I switched to valvaline synthetic dura blend and it is working out great for me, almost 4 months later and the oil is still clean. I changed it to synthetic at 160,000. 5-30 30 degrees and below and 10-30 for 30 degrees and above. What is recommended.