conventional or synthetic

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  #1  
Old 03-14-10, 11:57 AM
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conventional or synthetic

Yikes, another oil thread

We bought a new jeep this winter and it's getting close to time for the first oil change and I'm trying to decide whether to stick with the conventional valvoline like I always use or switch to synthetic.

The owners manual calls for oil changes at 6k, the dealer says that's too long and should be changed every 3k [like I've always done] but 6k will satisfy the warranty. I'm trying to decide whether to use conventional and change every 3k or switch to synthetic and change every 5k.

I e-mailed valvoline's tech dept but apparently they failed to read what I sent. They said you can't increase the miles between changes by using synthetic. They said I need to follow the manufacture's recommendation [every 6k] and not try to increase the miles between changes.

It appears the cost of conventional every 3k is about the same as using synthetic and changing every 5k. Any ideas or comments to help me make up my mind?
 
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  #2  
Old 03-14-10, 12:33 PM
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Originally Posted by marksr View Post
Yikes, another oil thread

I e-mailed valvoline's tech dept but apparently they failed to read what I sent.
Sounds like the answers I get when I email my Senators and Representative. Write them about gun control and they send you an answer about health care. Go figure.

I believe it would be whatever the life of the synthetic was. If it tended to wear out at 4K, I would stick with the conventional every 3k, or even extend it to 4k. I think 6K is too long. I change my oil when it gets dirty, period, regardless of the mileage.

It would still be cheaper than synthetic. I thought the purpose of synthetic was to give longer time between changes and protect the engine better.
 
  #3  
Old 03-14-10, 12:44 PM
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But how do you figure the life of the synthetic oil? The tire store I use has a sign saying they do 7500 mile oil changes [with whatever synthetic brand they use]. I don't want to extend the period between changes if it means the oil's going to be a lot dirtier
 
  #4  
Old 03-14-10, 01:06 PM
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I try to do every 5000 miles; easy to remember. A bit dated but interesting info (from ~1996 I think):
Consumer Reports, with one of the most widely respected product testing laboratories in the world has just released the results of an extensive test on oil brands and oil changes, as well as other issues regarding car care. In the process, the test demolished much of the conventional wisdom regarding car lubrication. The two most surprising results: the frequency with which oil is changed doesn't matter after the first few oil changes on a new engine, and the type or brand of oil used can not be shown to make any difference.

The testers placed freshly rebuilt engines in 75 New York taxis and then ran them for nearly two years, with each cab racking up 60,000 miles, placing different brands and weights in different cars and changing the oil at 3,000 miles in half the cars and 6,000 in the other half. At the conclusion of the test period, the engines were torn down, measured and inspected. The conclusions: Regardless of brand of oil or weight, no measurable differences could be observed in engine wear. Furthermore, there was no difference among cars which had oil changed at the shorter or longer interval.

Does this have any bearing on the enthusiast's car, which is given almost the opposite usage stored for long periods of time then started and driven for short distances? The tests suggested that our type of usage would build up sludge and varnish, indicating that an annual or semi-annual oil change is a good idea regardless of how much mileage the car is driven. But there is little indication that the brand or weight needs to be given serious consideration, and synthetic oil has no discernible advantage over the old stand-bys. More information on the tests and results can be obtained from Consumers Union or the July issue of Consumer Reports available at most libraries.

Source: British Car Magazine, October-November 1996
 
  #5  
Old 03-14-10, 01:26 PM
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3k? Jeez..are you guys still buying into that? Theres just no reason for it with modern engines and oils.

Now..maybe if its a 1950's Willys...but any modern vehicle should not need 3K changes....unless you are just beating the living snot out of it in the woods and mud every day.

6K conventional...prob at least 10k synthetic. I mean..the cars that have the oil sensor/oil change lights routinely go 10-12k.

I need to change my car oil next week...going to WA to visit son...this will be the first change in 18 mo....but of course I have only put about 5-6k since last change. Up until last July(?) we did about 400 a month..that's dropped to about 150. Matter of fact I need to get gas soon...last fill up was Feb 28. And that was cause we went to LV for the race...still sitting on a 1/4 tank...lol.

We occasionally drive it 20 miles or so to a restaurant we like..so that takes care of the water in the oil thing...plus its not really an issue here.

Of course diesels are a different animal.

I mean even click and clack say 3K is just giving your money to the oil companies. I think they say 5k or when the light comes on for fancy cars....
 
  #6  
Old 03-15-10, 04:57 AM
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Vic, it's hard to teach and old dog new tricks

My biggest concern with longer oil changes is the oil being dirtier. Since the engine calls for 5w20, I worry about the oil being good enough to give adequate protection long term. I understand that synthetic is supposed to protect the engine better but it costs too much if I can't stretch the mileage between changes.

Another concern with synthetic is if there comes a time when I can't afford the extra cost is it ok to switch back to conventional oil? I've heard some say no problem and other say that switching back to conventional oil will cause problems with seals, gaskets and such

btw - when I started driving we changed the oil every 2k although some would only change the filter every other change. I never did like leaving that quart of dirty oil in the engine. I don't remember when oil changes went for 2k to 3k.
 
  #7  
Old 03-15-10, 05:51 AM
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Originally Posted by marksr View Post
I e-mailed valvoline's tech dept but apparently they failed to read what I sent. They said you can't increase the miles between changes by using synthetic. They said I need to follow the manufacture's recommendation [every 6k] and not try to increase the miles between changes.
Their lawyers probably suggested this answer.

I use synthetic oil only in my track car but I know of many other track enthusiasts that use conventional oils. My car is a Porsche turbo with 180K miles on its clock. I change the oil every third track event and, so far, the car has survived over 100 track events over a 12 year period. I have another vehicle that is supercharged. The factory recommends synthetic oil so that is what is used. The other 3 cars use ordinary oil. All the other cars I have owned in the past went well over 100K miles and used ordinary oil. One of the 3 current cars is an exotic with a small and high rpm engine. I have owned it for 23 years and tracked it for 5 years or so. Conventional oil has always been used in it.

Under normal driving circumstances I do not think synthetic oils are advantageous. Frequent changes at 3-5K miles are more important. High oil capacities are also important when you think of circulation rate.

Just my opinion. Discussing oil is like discussing religion or politics......
 
  #8  
Old 03-15-10, 07:11 AM
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If you read your owners manual, it states the type oil and the oil change interval. They usually state NORMAL and SEVERE driving conditions. You should decide what driving conditions you fall under. I personally have done a lot of research on "oils" and have decided to continue to use what the engine has been using as long as it is a premium oil.
I would never switch oils in a vehicle with 12K or more. Synthetic and petrolium oils have different "oil swell properties" and you stand a chance of oil leaks if you switch.
Why take a chance???
I have even read where people mix synthetic with conventional oil.
It is amazing to me how many people recommend something to someone and they have not done research, only basing their recommendation on what they have read or been told. Just because someone has printed or published information, doesn't mean it is correct!
Experience is the best teacher, and my recommendations are based on that.
You should do your own research and decide what is right for your driving conditions.
 
  #9  
Old 03-15-10, 09:04 AM
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If its a poll your taking then
Put me down for conventional oil and factory recommended times.
I cant see harm in either scenario except with switching back and forth from synthetic to conventional.
I would also put the exact oil in a new vehicle that it came with. That way if something does go wrong, they cant wiggle out of the warranty
If I wanted to do something special for my new ride I would do oil analysis now and every 40 or 50 K later
Let us know if you need more info on oil analysis
 
  #10  
Old 03-15-10, 06:21 PM
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The owners guide just says to change the oil every 6k [or when the oil change light comes on] using 5w20. For some reason they don't have a provision for severe conditions.

I'm trying to decide what oil and how often to change [3k or 5k] I'm leaning towards conventional [possibly a synthetic blend] with 3k changes like I've always done.
 
  #11  
Old 03-15-10, 07:08 PM
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Originally Posted by marksr View Post
The owners guide just says to change the oil every 6k [or when the oil change light comes on] using 5w20. For some reason they don't have a provision for severe conditions.

I'm trying to decide what oil and how often to change [3k or 5k] I'm leaning towards conventional [possibly a synthetic blend] with 3k changes like I've always done.

marksr---Just type in a search ---"motor oil myths and facts"-- all this is good information and is well worth reading. It is supported by a few other sites I have checked out.
I have been a mechanic for over 50 years and I have always been skeptical of information I read and careful of recommendations.
 
  #12  
Old 03-16-10, 07:42 AM
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Ahhh see...you have an oil change sensor light and you still don't believe....lol. If its severe driving..the light will come on earlier.

The book says 6k or when the light comes on....if you have the extra money..just send it to me every 3k. No reason to pay the oil companies extra.

When the tank is empty..you don't just pump an extra 15 gal on the ground do you?

Boy mark...yer a tough nut to crack...
 
  #13  
Old 03-16-10, 01:36 PM
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Hey, don't you know it's hard to teach an old dog new tricks

I've probably read more about oil and oil changes in the last few days than I have in my entire life. It seems you can find an 'expert' to promote most any view point on oil changes
 
  #14  
Old 03-17-10, 03:57 AM
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As I said, an oil discussion similar to religion and politics....lots of opinions and few if any change their minds about it.
 
  #15  
Old 03-17-10, 06:51 AM
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Personally, I change my oil and filter every 3k using a hybrid oil (not really conventional and not full synthetic).

The oil change costs me about $20 and 20 minutes of my time.

A full years worth of oil changes is $80 and less than 1 1/2 hours of total time spent.

This way I know I have fresh oil, a clean filter, and I don't have to spend hours researching the "myths and legends" of oil changes.
 
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