Switch from conventional Oil to Synth

[HanibalTheCannibal]

Well, I picked up some Mobil1 5W-30 fully synthetic oil and a Mobil1 206 Oil Filter for my next oil change. I got to thinking. Is there anything wrong with there being a little trace of the conventional oil left in the engine? I know it would be only a little bit (3oz maybe). Just wanted to make sure that it doesnt "foam" up or anything weird like that when mixed with synthetic. I have never used synthetic before.

Also it says "15,000 mile", so how often do you really need to change this synthetic stuff??

Thanks!!

[2000CAYukon]

I ran conventional oil until I felt the engine was broken in and then I switched to synthetic. There was no foaming or any problems with switching.

I go about 7500 before changing synthetic. Part of that is that we don't put that many miles on the Yukon.

I am sure others will share their preference for changer interval.

//2000CAYukon

[HanibalTheCannibal]

Originally Posted by 2000CAYukon

I ran conventional oil until I felt the engine was broken in and then I switched to synthetic. There was no foaming or any problems with switching.

I go about 7500 before changing synthetic. Part of that is that we don't put that many miles on the Yukon.

I am sure others will share their preference for changer interval.

//2000CAYukon

Broken in? So it was new when you started using synthetic?? I just bought this truck. Its a 2001 LS 5.3 with 40K miles. I am sure it has had regular oil all this time. I would think this engine is broke-in already ?

[jethro_3]

Use it..... Go 5,000 on the first, use a test to see what is going on and then do what the test says on the second change.... Test and try....

[2000CAYukon]

Originally Posted by HanibalTheCannibal

Broken in? So it was new when you started using synthetic?? I just bought this truck. Its a 2001 LS 5.3 with 40K miles. I am sure it has had regular oil all this time. I would think this engine is broke-in already ?

I bought the Yukon new. I switched to synthetic when it had 10,000 miles on it. I have been running it with synthetic ever since. Now has 30,000.

//2000CAYukon

[misfitt006]

Originally Posted by jethro_3

Use it..... Go 5,000 on the first, use a test to see what is going on and then do what the test says on the second change.... Test and try....

I just swiched to a synthetic blend on my last oil change a few days ago....what test are you talking about? What are the advantages of using a blend over full synthetic or conventional?

[ctesla]

have ran the 15K extended mileage Mobil1 synthetic:
@15K visc. breakdown was still nominal (professional oil analysis)
and could have went another 3-5K, but I feel I got my money's worth.
actually started getting better gas mileage after 7500miles.
one thing people overlook when going with a 15K oil change:
you still need to change the filter every 3-5K !
and would suggest using Wix (CarQuest/NAPA are Wix as well), or Mann, or Mahle, or an AC Delco Duraguard Gold.

also, if you have ANY oil leaks, do NOT waste your money lubricating the driveway and highways, stick with a 20W50 conventional, and eventually take care of the leak.

if you are an off-roader, or run the vehicle exceptionally hard, would suggest changing at 10-12K, rather than 15K.

...as to the original question, conventional and synthetic blend (hence the synth/blend oil). the original "foaming" issue was back in the '70s when many were still using NON-detergented oils. with VERY strict and stingent SAE rules and regs, and "energy-conserving" motor oils, you can mix oils/brands/weights, etc.
now that I have said that, let me immediantely rekant: it is ALWAYS advisable to stick with same brand and weight (unless knowledgable in what you are experimenting with) and definitely have a "controlled" environment with your test vehicle as to what you are doing; however, one quart of Valvoline 10W30 in your four quarts of Quaker State 5W30 (or 20W50) will do no harm in the standard 3K-5K-7.5K oil change.
also small amounts of conventional will not significantly dilute your synthetic.

there are many sites on the web involving oil and filters:

http://minimopar.knizefamily.net/oilfilterstudy.html

http://www.bobistheoilguy.com/

http://home1.gte.net/vzep121w/ronspitstop/id27.html

http://www.oilchangeguys.com/oilbbs/
(these are just a few)

as long as regular maintenance is performed, longevity is to be expected.

hope this helps,
chris
nrt racing

[Rollingbones]

I 2005, GM was using an oil, part sythetic and part reglar oil. When I got my truck, I went straight to synthetic (Mobil 1 5/30) at about 3500 mils. No problems noted.

[jers99z]

would it be advisabe to change over in a truck that has had conventional oil in it for say 6 years and 80k miles. Im trying to do anything to extend the life of my truck and try to improve gas mileage

[jethro_3]

As stated earlier, change the filter as needed.

Use a test like this: Lab Test

[JCL82]

If you have alot of miles on your truck don't switch synthetic oil.told ya later the story...

[White Lightening]

Maybe I'm a bit confused. I've always believed the reason to use synthetics over conventional was higher heat handling and acid handling from hard use issues. If a truck doesn't have heat buildup problems - and doesn't accumulate acid because it is not worked heavily - why would synthetics alter m.p.g. or be desireable unless you drove alot of miles a year?

I guess I figure if you have to change the oil filter every 3K to 5K - might as well change the oil at the same time. Especially the case - the newer Silverados with the oil monitor is monitoring the oil for usability as I read on one of the other threads (monitors not how clean - but lubricant capability).

Input appreciated.

White Lightening

[jethro_3]

Why is it that people can find the most unrealistic reason to refute the capability of Synthetic Oil?

Don't break in new, Don't use on old engines, Can't use farther than 3K miles, my dad did not use it so I can't, I know the book does not say 3K miles but I don't believe the book, I know the Corvette uses it from start up but that is different ... Hell, synthetic it is a governmental hoax????

Evil, Evil, Stay Away, Evil, Evil!!!!!!

I got it, I got it, the story about my heighbors cuzin's brother's lover said so.....

Ok, rant over, pick a reason to not, someone will give you a good reason not to do it!!!!!!!!!! I'm sure you can find Oil in the origonal form like it was designed in say the early 1900's to use......

[jveik]

why is everyone so nitpicky about the oil they use? get the right weight then it doesnt matter as long as you change it when needed. its all the same

[robjen]

I had a 93 s10 blazer that I switched over to mobile 1 at 120k. And I didn't have any problems. Just make sure you change it after 2k for the first oil change. The syn will clean your insides. As for leakage. I had a slow leak on the botom of the motor and when I switched over, it actually quit leaking.
I now use nothing but amsoil in my new truck. I put it in after about 7k miles. And I change it every 5k miles. Oil is cheap insurance.