Synthetic oil in 4-cylinder vehicles

Recently my auto mechanic informed me that 100% synthetic motor oil is not recommended for 4-cylinder engines. He informed me that a synthetic blend in the oil best suited for a 4-cylinder. Is this true? I have been using a pure synthetic in my 4-cylinder Toyota Camry. Am I doing any harm to the engine with synthetic oil?

What type of oil does your owner’s manual recommend?

There is no set rule for all four cylinder engines. It varies by car and engine design.

Your mechanic’s advice is sort of the automotive equivalent of someone telling you that you shouldn’t eat celery if you have red hair. Ergo–incorrect, and somewhat bizarre.

Are you doing any harm to your engine? No
Are you paying a premium price for something that you likely don’t need? Yes

Unless your part of the country is typically exposed to extremely low temperatures (sub-20 degrees Fahrenheit) in the winter, there is really no advantage to synthetic oil. If you live in more temperate areas of the US, conventional motor oil in the viscosity specified by Toyota is all you need. Also, be sure that you don’t exceed 5k miles between oil changes–whether you use conventional or synthetic oil.

Synthetoc oil is only recommended for 4-bangers when they have turbos. Your Camry does not.

Turbochargers, because the turbos are spun by the hot exhaust right out of the manifold, at very high speeds, and are lubricated by the oil, expose the oil to much higher temperatures stresses than your Camry engine does. Since synthetic has been shown to better stand up to high temperatures, it’s used in turbocharged engines.

Your engine does not need synthetic. He’s being honest in suggesting that synthetc is not “recommended” for 4-bangers (he’s no doubt assuming you’re talking about your Camry, which is not turbocharged). It’s simply not necessary. That’s not the same as saying that synthetic would be bad for 4-bangers, only that there’s no need to use it.

There are those who feel that “blended” oils provide better protection for all engines without the added cost of full synthetics. Apparently your mechanic is one.

I believe he’s being honest and saving you unnecessary expense.

Hogwash, there’s no reason why a 4 cylinder can’t use synthetic oil. There’s no reason why you can’t use it in your Camary if you choose to do so. Now you probably won’t see any huge benefit in using synthetic oil. But you won’t hurt anything. I would look for another mechanic if I were you, next thing you know he’ll be wanting to de-coke your valves and revulcanize your tires.

tsm is right on this one, your mechanic is being straight with you about your car, and saving you money, stay with him and be glad you found an honest businessman to work on your car.

Here we go, another 40 posts for sure…One Cylinder or sixteen cylinders, it makes no difference…I would not let your “mechanic” work on my lawn mower…

Here’s a new version of the old ‘synthetic yes or no’ question. This is actually a grammar question. “not recommended” is different than “not required”. “not recommended” infers something negative will happen if you use synthetic, which (aside for the extra money you spend) is not true, no harm will come. Had he said “not required” or “not needed” (for Camrys, at least), he’d have gotten an ‘A’. As is, he gets a ‘C-’.

harsh texas, harsh.

Well, if your Camry has one of the sludge prone engines, then he’s doubly wrong. If you’re a DIY’r …the cost of some synthetics (many of which are NOT marketed as extended drain oils - in fact, VERY FEW ARE) is not too far above conventional and is easily justified in a (perhaps) situation like yours.

Otherwise, a synthetic will not extend the life of your engine. It will probably last longer itself under more stressful conditions than a conventional. It will take more heat, it will flow slightly easier when cold. It will endure oxidation better/longer.

The sludge-o-matic was a V6.

I can understand someone saying that synthetic oil is NOT needed and that regular dyno will suffice. But I have a hard time with someone saying NOT to use synthetic…ESPECIALLY FOR A 4 CYLINDER ENGINE. 4-cylinder engines are more likely to NEED synthetic oil then a V8. I’d find a new mechanic if I were you.

That may ont be what he said.

“Not recommended” is not quite the same as not “recommended”. The first says “do not use”, the second says “not necessary”. Based on the OP’s mechanic having suggested a blend instead, I suspect he meant “not necessary”.

Myself, I wouldn’t “recommend” a 100% synthetic for a non-turbocharged 4-banger. I think it’s a waste of money. But that doesn’t mean I think it would be bad for the engine.

Give your mechanic a chance to clarify his statement and tell him his use of every single word will be scrutinized, and don’t you add or subtract from his statement, this is of extreme importance.

The sludge-o-matic was a V6.

Oh, really? It clearly seems that the 4 bangers got extended warranties just like the V6 due to sludge issues.

This is an Amsoil bulletin, not a Toyota TSB. Naturally, it recommends Amsoil in numerous possible configurations of numerous possible engines.

Find me a Toyota TSB covering 4-bangers and I’ll concede.

Show me one that exempts it and I will.

Those 4 bangers got extended warranties. Forget the Amsoil recommendations

My friend, you’ve yet to show me anything from Toyota that talks in any manner to sludging of their four cylinder engines. Not a TBS, not an extended warranty. Until I see a TSB from Toyota addressing sludging of a four cylinder, I’ll rest my case. I’ll not be put in a position of trying to disprove something that’s not been proven.

Agreed entirely. I can’t figure out why your mechanic would say this at all. I thought I’d heard a lot of the BS car wisdom out there, but I’ve never heard anyone say this.

You need a new mechanic. Preferably one that did not go to the Voodoo school of auto-shop.

But VDC is also correct that there’s no real advantage to synthetic. I love all three of my vehicles in an almost unhealthy way, and pamper the heck out of 'em, but they get regular dino-juice for their oil. Synthetic is not necessary and costs a lot more money which could be better put toward a spiffy new mod for one of the cars.

Naturally. It’s real simple

Toyotas covered by the Louisiana settlement include the:

? Camry 4 cylinder from 1997-2001,
? Camry 6 cylinder from 1997-2002,
? Camry Solara 4 cylinder from 1999-2001,
? Camry Solara 6 cylinder 1999-2002,
? Sienna 6 cylinder from 1998-2002,
? Avalon 6 cylinder from 1997-2002,
? Celica 4 cylinder from 1997-1999,
? Highlander 6 cylinder from 2001-2002,
? Lexus ES 300 from 1997-2002 and
? Lexus RX 300 from 1999-2002.

In 2002 Toyota admitted receiving 3,400 complaints about sludged engines and the automaker extended its vehicle warranty to eight years along with unlimited mileage to owners of 1997-2002 Toyota and Lexus vehicles equipped with 3.0-liter V-6 or 2.2-liter four-cylinder engines.

Read more:

…but insist on the evidence ONLY being valid under YOUR CONFIGURED CONDITIONS. Nice and convenient that way. :smiley: