Late switch to full synthetic?

[MichaelRS]

My 2002 Sienna has nearly 204k miles on it and I got it 70k miles ago in 2012. Ever since I've been running Castrol's GTX High Mileage synthetic blend in it. I use premium filters and try to shoot for oil changes around 5000 miles or a bit less. I just got my most recent oil analysis back from Blackstone (pictured) and the numbers are all pretty good. Sooo...

I'm wondering if at this late date and after all this time there's any real benefit to me and switching to a high mileage FULL synthetic?

The benefits I think there would be, or I would be looking for, would be those generally associated with engines and full synthetic oil as well as extending my OCIs a couple thousand miles.

But I'm also wondering if after all this time that.... well, I really don't know any other better way to say it, so I'll just say it in a way that probably sounds a little ignorant... maybe the internal parts of my engine are held together by 204,000 miles of conventional or blended oil gunk and full synthetic oil might clean that all out and cause problems.
Thoughts?

 

[scm]

By switching to a full synthetic, not even high mileage, you could easily get 7,500-10K out of a single oil change.

This is a perfect use case for Super Tech/Amazon Basics/Kirkland Signature Oil... all made by Warren with a solid additive package.

 

[Mad_Hatter]

Have you noticed any sludge in the filter or oil? The odds of you having a sludged up engine are actually pretty low if you've been good about changing the oil on time. Unless you're looking to push out your drain intervals I don't see a compelling reason to switch. Today's blended oils are waaay better than the oil that was around when your Sienna was mfg.

And what's up with the silicon levels in the UOA, you got a poor fit on the air filter housing or something??

 

[Snagglefoot]

Originally Posted by Mad_Hatter


And what's up with the silicon levels in the UOA, you got a poor fit on the air filter housing or something??


Has the OP driven through fire smoke much. Some of the smoke particles can make it past normal air filters. I experienced that a few years ago.

 

[alarmguy]

If your looking to extend OCI's synthetic is the way to go, that is the only benefit.
Synthetic isnt going to clean out anything more then the oil you are using.

 

[danez_yoda]

You probably have varnish but not sludge since GTX is a good oil and your OCI is low. Most conventionals will form varnish over time/miles. Most synthetics will not. Varnish looks bad but in my opinion is harmless unless it is severe. Doubtful it is sever in your case with GTX and your stated OCIs.

If you can get the GTX at a good price compared to Supertech synthetic, why not keep using it? I know quite a few toyotas that ran conventional oil out to 300-400K miles with 5K OCIs. Sold or retired the vehicle still running and burning little to no oil.

 

[kschachn]

This is another instance of what I call imaginary sludge, no indication of it whatsoever but now somehow it is a worrisome problem. Usually people want to use some additive or flush to clean out the imaginary sludge, but in this case it is imagined it is doing something good and the worry is that if removed it will cause problems.

As someone who has operated a 1MZ-FE for over 430,000 miles you can't tell anything without looking. And you can't look in the oil fill hole either since a baffle (coated with a black gritty substance from the factory) is blocking your view. You must either remove the oil pan or the valve cover, preferably the rear one to make a visual inspection. This isn't uncommon to do since valve cover gaskets regularly leak on this engine and require replacement.

If you've been using a reputable brand of synthetic blend oil at 5000 mile intervals then you are fine. And given the relatively low cost of Supertech full synthetic oil there is no reason not to use it in this engine.

 

[metroplex]

I'm starting to think the 5k oil change interval is the safest bet regardless of the oil used.

 

[tig1]

Originally Posted by alarmguy
If your looking to extend OCI's synthetic is the way to go, that is the only benefit.
Synthetic isnt going to clean out anything more then the oil you are using.

Originally Posted by metroplex
I'm starting to think the 5k oil change interval is the safest bet regardless of the oil used.

The 42 years I have done 10K OCIs with M1 would highly disagree with you.

 

[demarpaint]

Originally Posted by metroplex
I'm starting to think the 5k oil change interval is the safest bet regardless of the oil used.

That depends a lot on the driving conditions, the vehicle, and the oil used. I'd get a UOA and be sure, especially if I were inclined to believe blanket statements often found here. Many of them would have gotten me into trouble.

 

[WyrTwister]

Oil / filter change is cheap insurance . It is changed for more or less the same reason you flush the commode .

Just purchase a " good " synthetic on sale and use it . And rest easy .

If you are worried , substitute 1 quart of synthetic , first time around . Next time 2 quarts . Repeat until it is all synthetic .

 

[Duffyjr]

Even if I switched to synthetic I wouldn't start extending the OCI on a vehicle with 204k, I think most would agree as engine miles increase you should change oil more often not less.

 

[Mad_Hatter]

Originally Posted by Snagglefoot
Originally Posted by Mad_Hatter


And what's up with the silicon levels in the UOA, you got a poor fit on the air filter housing or something??


Has the OP driven through fire smoke much. Some of the smoke particles can make it past normal air filters. I experienced that a few years ago.

I have no clue what he's driving through but wouldn't the test equipment used to determine elemental content/amounts be able to discriminate between soot and silicon? The "lab" for a company i worked at (i did sales) used a PerkinElmer equipment that used a flame to burn a solution and the different wavelengths gave them a number that the lab tech could then extrapolate a ppm figure of the element in question. So it was a discrete analysis. Can't recall the name of the equipment offhand but that was one piece of equipment they used for elemental analysis the other was a ftir(?) I think...

 

[JeffKeryk]

Those darn Toyota engines...

 

[The_Nuke]

If you want to switch oils to something more synthetic, why not switch to something like Valvoline HM which is marketed as a synthetic blend? That way you don't shock the system by going fully synthetic after so long on Dino, not to mention that's some pretty good oil in its own right.

Possibly applicable anecdote: I was in a similar scenario as you with my car at 150K on its clock. I switched to ST synthetic, and after an OCI of that, I had myself a small oil drip develop.

Attributable to the switch to synth? Maybe, not conclusive though for sure...

Nevertheless, I switched again after 2 OCIs on the ST synth and started running Valvoline HM. After 3 OCIs, the drip dried up.

Attributable to the switch to Valvoline HM? Maybe, not conclusive though for sure...heck of a coincidence, but not conclusive by any means.

 

[BLND1]

I don't agree with the reasoning behind this but I agree that valvoline maxlife synblend was designed (and marketed

for exactly this.

Originally Posted by The_Nuke
If you want to switch oils to something more synthetic, why not switch to something like Valvoline HM which is marketed as a synthetic blend? That way you don't shock the system by going fully synthetic after so long on Dino, not to mention that's some pretty good oil in its own right.

Possibly applicable anecdote: I was in a similar scenario as you with my car at 150K on its clock. I switched to ST synthetic, and after an OCI of that, I had myself a small oil drip develop.

Attributable to the switch to synth? Maybe, not conclusive though for sure...

Nevertheless, I switched again after 2 OCIs on the ST synth and started running Valvoline HM. After 3 OCIs, the drip dried up.

Attributable to the switch to Valvoline HM? Maybe, not conclusive though for sure...heck of a coincidence, but not conclusive by any means.

 

[MichaelRS]

Originally Posted by Mad_Hatter
And what's up with the silicon levels in the UOA, you got a poor fit on the air filter housing or something??


About a week before the oil change I had the major tune up with the spark plugs and replaced all my rear rear ignition coils and the upper manifold gasket as well as having my air intake cleaned out. Blackstone thought that the slightly elevated silicon might be related to that somehow.

No, actually I do not suspect sludge at all.
I was aware of that potential problem with these first-generation Sienna's and so inspected for that the best I could before I bought it in 2012 with 136k on it.

Then after I bought it I did have the oil pan dropped and inspected and cleaned and there was no indication of it sledging there either.
I actually started using the Castrol High-Mileage which is, like the Valvoline, a synthetic blend.

What I was talking about something being held together in my engine having run on conventional or blend oil for the last 204k miles and then being knocked Loose by the sudden introduction of full synthetic was just some worrisome thinking.

I really don't know what oil the original owner ran the first 70k but according to Carfax he took very good care of it because there were reports on it of regular general service through Toyota dealers.
The guy I bought it from at 136k was kind of sketchy on the oil he used and changing and all that. I don't think he was being shady about anything but he was Vietnamese and there was a slight language barrier.

Well, I thank everybody for their input. I think I'm just going to stick with what I've been doing. Maybe I'll just move up to 5K OIC and see what the analysis says there.
Thank you all again for your opinions and advice