Conventional to Synthetic?

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Ok, I have been on here a long time. I have read 1000's of posts. But my situation is different, right? (Typed with tongue in cheek)

A little background...

For the last 30 years I was an Amsoil addict. I say this respectfully no bashing. I faithfully used many of their products, even their vitamins.
About 5 years ago, I started weaning off their engine oils and ATF's. I am still 100% in their Severe gear oil and grease camp.

I am now having to deal with 30 years of synthetic bias. I have never purposely gone 10k on any oil change. Normally go 5K.

My son is purchasing a '09 Highlander with 138,000 miles. We have all the service records from Toyota. Most OCI's were 5k and 2 went
7k. Everything was done at the same dealership. I called the Service Dept yesterday and they looked up by the VIN and said they used 5W-30 Mobil conventional engine oil in it.

I guess you have already anticipated my question. I am anticipating some chastising and ridicule so I won't be caught off guard and am expecting
some of you to give me a hard time.

Here is my question:

Based on the most excellent service history of this car, would I be making a mistake switching over to say Supertech Synthetic 5W-30? Or switching over to Supertech High Mileage Synthetic 5W-30? Or should I just go with a Synthetic Blend? Or stay with the Conventional?

Some of you may understand how I am trying to think with my head but my doggone heart still pulls me to the "synthetic." To be truthful, I guess I am posting this for therapeutic reasons. After 30 years of believing a thing I find it very difficult to change my thought process.

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If there is any kind of minor oil leak, I would stay with conventional. If there is no sign of any leaks, I would consider synthetics and keep an eye out for leaks. I simply buy what is on sale at the time, synthetic or conventional.
 
use whatever is cheapest, synthetic, blend, conventional (which is basically a blend anyway with SN+).
With Supertech syn being jug, it is a very convenient choice. If you wanted to go HM, the ST HM Syn is the same price that has a bit better add pack, but would probably not make any difference.
ST conventional (and HM) is only $1 cheaper right now, so I would just go with the syn now, and maybe to ST conventional HM if the price goes back to $18/jug.
 
I would meet in the middle with Havoline PRO DS. Its only a few bucks more than conventional supertech, and alot cheaper than Amsoil.
 
After 100K, I went from Mobil One to Stupertech Full Syn HM 5w-30. So far I have gotten an excellent UOA report on the oil. Most conventionals are so close to OTC synthetics anyhow, it really doesn't matter much.
 
Why the need to change to syn oils? What has using Amsoil syn bought you?
 
I normally wouldn't suggest a synthetic blend but why don't you start out with that and see how it goes...then go full Synthetic. Personally I'd just use a full Synthetic and not think twice about it, but where you're having some questions/doubts, start off slow.
 
Originally Posted by CT8
Why the need to change to syn oils? What has using Amsoil syn bought you?


I can't say for sure. I know that. I do have some old stuff with many miles but I can't say Amsoil had anything extra to do with it.
 
If you're going to change it out every 5000 miles, I don't see any benefit switching to synthetic. If your son is living at school or for some reason might not make it home in time for 5000 mile OCI, you might want the peace of mind of using synthetic, knowing he's good for 10, 000 miles and if you need to stretch the OCI past 5000 miles, you won't lose any sleep.
 
So do Valvoline Maxlife FS or Mobil1 EP HM either will both address potential seal seepage concerns while still providing the better base oils you're after.
 
Originally Posted by GZRider
So do Valvoline Maxlife FS or Mobil1 EP HM either will both address potential seal seepage concerns while still providing the better base oils you're after.



Hmmm... I like this idea. Just use a full synthetic High Mileage...

I'm feeling better.
 
FWIW I've switched vehicles from unknown or dino to synthetic at up to (I think) 105,000 miles. Worst thing that happened was a little seepage around the main seal, which dried up within the first OCI. So no worries about switching if you want to.

As far as the dino vs syn....5000 miles is a good interval for most dino oils, one UOA and you'll know if it's good to go. If going 7500 or more, synthetic.

All that said, as mentioned with current prices might as well use ST Synthetic.
 
While reading your post I was thinking ST synthetic all the way. Its a good oil that doesn't have aggressive cleaners in it. Be careful with high mileage as there might be some cleaners in there that will act before the seal sweller.

Might be worth a borescope look in the valve covers to see if there is heavy varnish showing in there from the conventional oil. If not (likely) you have no worries with synthetic unplugging some varnish deposit that is stopping a leak.

Really wound not have a problem with continuing with conventional as well. My brothers 06 tundra got 300K miles with conventional then switched to Valvoline max life semi some time before he sold it. it still ran perfect.

Hat to say it now but you wasted a lot of money on Amsoil synthetic running only to 5K miles. They were justifying the price by saying you could run to 25K miles.
 
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No reason not to go synthetic these days. I've used synthetics in various older and/or high mileage vehicles with unknown maintenance history... No leaks or consumption issues.
 
FWIW: My son's, girlfriend's 07 Sienna was a family-owned vehicle that got 5k OCIs on conventional oil until 2 years ago. The vehicle had 125,000 miles when the family vehicle was handed down to her. I help her maintain the vehicle and use milesyn 5w-30 full synthetic every 6k miles.

Someone forgot to tell this engine that it was supposed to spring leaks and start burning oil when switching from conventional to synthetic. We're on our 4th oil/filter change now and the outside of the engine is dry as a bone. It's a V6 that holds 6 quarts and after 6k miles, I drain about 5-3/4 quarts out.

My 1998 Corolla was born/raised on conventional oil for 70,000 miles with 4k OCIs. At 70,000 miles I switched to synthetic and 5k OCIs then up to 6k OCIs and never looked back.


Ray
 
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