[Fok Voort]

I am recently responsible for the maintenance on an '01 V6 Highlander. It was very well maintained for its first 50K miles, then was driven another 30K miles without any maintenance -- not even an oil change. :facepalm:

At 80K miles I took over its care and had all fluids changed using OEM fluids. At 85K miles, did the engine oil again, again with OEM dino oil.

I'm a devoted synthetic oil user in my own cars; the Highlander has had dino its entire now 90K mile life.

I would like to make the switch, and under ordinary circumstances would feel comfortable doing it, but I'm worried about that 50K to 80K stretch where the oil wasn't changed, given the sludge issues this series of engine has associated with it.

Would a switch to synthetic under these specific circumstances be advised, not make a difference, or risk problems?

 

[bepperb]

My opinion, not make a difference.

Understand that "synthetic" can mean many things, including Group 3 synthetic which is just a further-processed mineral oil, and group 4/5 PAO's and Esthers. The group 3 oils certainly have advantages over group 1 and 2 conventional oils, like a lower volatility, higher viscosity index... etc... but they have no cleaning advantage over just a straight conventional. Most of the less expensive "synthetics" are of this base stock, or a blend of it and some group 4/5. That's not to say they couldn't have some additive to do more cleaning, and I'm sure many do, my point is that the term "synthetic" in the US is a pretty vague one and there isn't a huge difference between a cheap synthetic and a good dino anymore. With API spec SN coming this fall the gap will narrow even further. Really, what I would look for would be a high mileage oil where you would be assured enhanced cleaning ability, and you could definitely get a synthetic or synthetic blend if that's what you wanted.

Really, what the concern might be is that using a higher detergent oil would be cleaning the valve guide seals of whatever deposits they have on them and actually increasing oil consumption. The risk of this, and even if it was a guarantee, IMO is outweighed by the fact you need to get this engine clean especially considering it's history of being sludge prone.

So if it were mine I would, at the very least, change over to a High Mileage oil and perhaps a synthetic at that. You might also do some reading/searching over at bobistheoilguy.com/forums and see if you're interested in using something like autorx that might clean more aggressively.

There's nothing special about Toyota OEM oil, besides their 0w-20 which is fantastic but expensive.

Have you considered pulling a valve cover to see how bad things are?

 

[teppista881]

I agree that high mileage oil will be a good choice, perhaps with shorter change intervals of 2.5k miles or so. Valvoline MaxLife synthetic blend (the cheaper MaxLife) is my very unscientific preference.

+1 also to popping the front valve cover to inspect the "damage." Could be very bad sludge, and if not, at least the valvetrain is probably covered with varnish with some pockets of sludge. In either case, a more aggressive treatment like Auto-Rx might be in order.

 

[Fok Voort]

My opinion, not make a difference.

Understand that "synthetic" can mean many things, including Group 3 synthetic which is just a further-processed mineral oil, and group 4/5 PAO's and Esthers. The group 3 oils certainly have advantages over group 1 and 2 conventional oils, like a lower volatility, higher viscosity index... etc... but they have no cleaning advantage over just a straight conventional. Most of the less expensive "synthetics" are of this base stock, or a blend of it and some group 4/5. That's not to say they couldn't have some additive to do more cleaning, and I'm sure many do, my point is that the term "synthetic" in the US is a pretty vague one and there isn't a huge difference between a cheap synthetic and a good dino anymore. With API spec SN coming this fall the gap will narrow even further. Really, what I would look for would be a high mileage oil where you would be assured enhanced cleaning ability, and you could definitely get a synthetic or synthetic blend if that's what you wanted.

Really, what the concern might be is that using a higher detergent oil would be cleaning the valve guide seals of whatever deposits they have on them and actually increasing oil consumption. The risk of this, and even if it was a guarantee, IMO is outweighed by the fact you need to get this engine clean especially considering it's history of being sludge prone.

So if it were mine I would, at the very least, change over to a High Mileage oil and perhaps a synthetic at that. You might also do some reading/searching over at bobistheoilguy.com/forums and see if you're interested in using something like autorx that might clean more aggressively.

There's nothing special about Toyota OEM oil, besides their 0w-20 which is fantastic but expensive.

Have you considered pulling a valve cover to see how bad things are?

I'm iffy about pulling the valve cover because I'm inexperienced with Toyotas and it's not my car; I've taken responsibility for its maintenance because its owner doesn't and they're family.

In my own cars I use Group IV basestocks like Mobil-1 SuperSyn and German Castrol.

I'm skeptical of engine cleaning additives like AutoRx and SeaFoam, finding the arguments for their potential to do harm compelling.

You nailed it on my concern about switching to a synthetic: the detergent might dislodge some gunk and cause a problem where otherwise there wasn't one. Car's made it to 90K on dino without problems; although the series is known for sludge issues, this particular engine has no history of it. It was dealer maintained until 50K, then had it's neglected period to 80K, then back to dealer maintenance since. (The dealer's mechanic did note how bad the oil looked when I took it in for the first change in 30K miles, and mentioned the sludge risk, but didn't note a specific problem.)

On the other hand, it's possible that there's build-up waiting to be a problem that sticking with dino will only add to that, but putting a quality synthetic in might help.

 

[bepperb]

German Castrol is the real deal. Probably wouldn't go for that here, considering price and future availability. Same thing with something like M1 EP, a great oil but if there's a chance of sludge more frequent changes with a lower quality oil would be better to clean things out.

Have you also considered something like a Rotella 10w-30 diesel oil? That would also have quite a bit of cleaning additive over a normal passenger car motor oil and it is still a conventional (and very good) oil. It is also still rated SM for passenger car use (IIRC with the new "T5" formulation).

Also, the dealer bulk will probably be Formula Shell, Exxon Superflo, TropArctic... etc. It would be uncommon for a dealer to use quarts of a branded oil (though not out of the question).

If it's not yours, your best advice might be to have them go wherever and get it changed say every 3000 miles for a couple changes, then stick to 5000 thereafter.

 

[shortlid]

Diesil oil!!

Have you also considered something like a Rotella 10w-30 diesel oil? That would also have quite a bit of cleaning additive over a normal passenger car motor oil and it is still a conventional (and very good) oil. It is also still rated SM for passenger car use (IIRC with the new "T5" formulation).

Also, the dealer bulk will probably be Formula Shell, Exxon Superflo, TropArctic... etc. It would be uncommon for a dealer to use quarts of a branded oil (though not out of the question).

If it's not yours, your best advice might be to have them go wherever and get it changed say every 3000 miles for a couple changes, then stick to 5000 thereafter.

I also recomenet fleet or Diesel oil. That stuff has WAY more detergents than passanger vehicle oil to put up the the soot diesels create!!

 

[Tydog07]

I don't have the attention span to read all the posts but judging from the title, and the fact it's a Toyota, I say go for it!

 

[lqueral]

try this

I'd be tempted to change the oil (any oil) but leave out half a quart and make this up with .5 quart of Dexron ATF fluid. Leave this in for several hundred miles and change oil and filter again, but use all motor oil. ATF has a much higher concentration of detergents and should polish up the internal surfaces of the engine. I've actually done this on several vehicles and left it in for 3k miles, but with this engine being a sludger, I'd only go several hundred miles (less than 500).

 

[AVConsult]

I would not put transmission fluid in the crankcase.

You might use one of the reputable "sludge dissolving" oils, by Quaker or Penz. Walmart carries them now. For abused engines, Seafoam also works gradually and thoroughly as well. Directions on bottle.

 

[lenore]

I have found the German Castrol oil does a great job of cleaning...The caked on burnt oil under the filler cap even dissappeared..I changed to it at 110k miles on my Lexus RX300 and now have 182k miles....no problems....

 

[teppista881]

I have found the German Castrol oil does a great job of cleaning...The caked on burnt oil under the filler cap even dissappeared..I changed to it at 110k miles on my Lexus RX300 and now have 182k miles....no problems....

Good to know. I've got 5 qt sitting my garage and hadn't decided which car I want to put it in. I think this might settle it for me.

 

[Dante's Taco]

Resurrecting an older thread.

As some of you know, I recently picked up a used 2001 LE, with the dreaded 1MZ-FE sludger. I have dealership service records from previous owner back to 2007, but the 2001-2007 interval is unknown. I have noticed from 2007 -2011 they were a bit liberal on their OCI, and it was certainly dealership el-cheapo dino that Red Deer Toyota put in for the reported price. However... does not burn oil so far at 4,500 km since last change; no blue smoke on start-up. Too cold here to pull valve cover (unheated garage :thumbsdow)

So...

Where does one get true German Castrol in Canada? Or even can you?
Failing that, my plan is then to fall back to something like Mobil-1 High Mileage Oils and short OCI x2 or 3. Cost is a non issue.

I do have a can of SeaFoam, but am really disinclined to pour that or any other potion into a crankcase of unknown status (Have used it on my Tacoma, but then I am sole owner & have done synth oil changes religiously at the severe service interval, so I know sludge risk low there)

I will also check all crank-case ventilation hoses & PCV when warmer.

Open to any other sound advice & not afraid to wrench.