Urban Legend from decades ago ... synthetic oil was "too slick" for engines

[TomYoung]

Maybe at first, but they fixed it with anti-slickness additives. (Pay attention so you get your facts right, ChatGPT!)

Can you document either "fact?"

 

[Patman]

boomers to me is more or less anyone born before like 1980. That or they have the same mentality as someone born in 1920.

Baby boomers are the generation born between 1946 and 1964, as this was when there were more babies born shortly after WW2, therefore they were part of a “baby boom”

 

[JAG]

I don’t know if issues happened in engines that were related to this, but there are indeed significantly different traction coefficients for different base oil types. Additives also matter, of course. Read this: https://www.mdpi.com/2075-4442/6/3/73
It compares Group 3 to PAO, which are obviously more similar than Group 1 is to PAO. Esters are different as well, and they vary a lot.

 

[Kestas]

I asked our seal engineers if there were problems with synthetic oil and sealing. The answer I got was that they test seals in the oil specified for the application. They don't do any contingent testing.

 

[ripcord]

Can you document either "fact?"

It was a joke. Totally not true

 

[Propflux01]

What is Syn3? Something with the HD trademark on the bottle and priced accordingly?

Yes, it is Harley's version of synthetic oil. Its called Syn3 because at the time it was suitable for use in all three holes, engine, primary, and transmission.

 

[Learn Ya]

Don't forget, the other thing that mechanics wre saying at the time was that synthetic oil would cause your car to leak/use oil.

I remember that. People also said that once you switch to synthetics, you can never switch back to conventional oil.

The previous generation (my grandfather) said the same thing about detergent vs non-detergent oil.

All myth. No science.

 

[Astro14]

boomers to me is more or less anyone born before like 1980. That or they have the same mentality as someone born in 1920.

Wow. That’s some serious generational stereotyping, there. Ageism much?

 

[Astro14]

I remember that. People also said that once you switch to synthetics, you can never switch back to conventional oil.

The previous generation (my grandfather) said the same thing about detergent vs non-detergent oil.

All myth. No science.

Not the same at all. Not even close. Huge science behind the non detergent to detergent switch.

The non detergent allowed deposits to build up, particularly in the pan. Switch to detergent, loosen the sludge, plug the pump, or even just lifters and galleries, and you kill the engine.

Until you have scraped out inch thick sludge from an engine run on non detergent oil, you have no idea how bad those deposits can get, and how quickly the could kill the engine.

This was a very big deal in the collector car community for decades following the introduction of detergent oils.

I believe that SB was the first API specification that required detergent - c. 1951 or so.

You won’t find many cars these days that have been run exclusively on non-detergent and never rebuilt or cleaned out.

 

[Speedy3861]

When i restored my 66 Corvair in 2003, including all Viton O rings, hardened valve seats, roller-tip rockers and replaced the points with an electronic module, my initial concern was finding an oil with 1960's levels of ZDDP. Because of the cam and flat tappets I tried several synthetics including Brad Penn. Finally found a 10W-40 from Amsoil that worked well with over 1400ppm ZDDP. Mine was a 164ci 110hp that required Premium fuel. Most synthetics now have much lower levels of Zinc & phosphorus mostly to protect catalytic converters and emissions requirements. There are several synthetics and semi-synthetics for classic cars now, an easier find. With all the ratings and approvals I can't find a single reason not to use any of the quality synthetics. In the 60's all my Volkswagens used Quaker State 30HD summers an 20HD winters, I never ran any non-detergent oils. Never understood Semi or Part-Synthetics,
Don't know why Ford stuck with the Motorcraft semi-synthetc so long, but a lot of people use it with good results.

 

[The Critic]

I asked our seal engineers if there were problems with synthetic oil and sealing. The answer I got was that they test seals in the oil specified for the application. They don't do any contingent testing.

Anecdotal evidence only: a few vehicles I regularly serviced had run M1 and other major brand synthetic oils at shorter than OEM intervals. They had minor seepage from valve cover gasket or RTV timing cover seal. Upon using non API certified engine oils with a known heavy ester content, the seepage became exponentially worse within one OCI.

 

[Learn Ya]

Anecdotal evidence only: a few vehicles I regularly serviced had run M1 and other major brand synthetic oils at shorter than OEM intervals. They had minor seepage from valve cover gasket

Anecdotal evidence: I have a 2000 Jeep Cherokee XJ 4.0L with 220,000k+ on the clock. My valve cover (and everything else) leaked like a sieve with any oil...since Mile #1. LOL! Thus, I stopped chasing leaks many years ago.

It all depends on the application and circumstances, I guess? That's the joy (or misery) of vehicle ownership.

 

[Learn Ya]

Until you have scraped out inch thick sludge from an engine run on non detergent oil, you have no idea how bad those deposits can get, and how quickly the could kill the engine.

Good info. I have no experience with that. I was born after the non-detergent era...thankfully.

 

[cammyfive79]

IF synthetic was “too slick” - why, in those years, did high end sports cars get delivered from the factory with synthetic? The Corvette came with Mobil 1 for example, so…was Honda behind GM in engineering and manufacturing back then?

A service adviser that didn’t know what he was talking about and made up words like “too slick”?

And you believed him?

Really?

Calm yourself. I was asking why people thought this at the time or how this urban legend originated as it was pretty prevalent online at the time.

 

[Hohn]

boomers to me is more or less anyone born before like 1980. That or they have the same mentality as someone born in 1920.

That’s because you seem not to know what the term means.

Boomers were born between 1945 and 1964. Gen Xers like me are from 1965-1980.

 

[k1xv]

I remember, in the early days of Mobil One, the rumor that you should only use it after break in.

Because if you used it before the engine was broken in, it was so slippery that no parts, such as piston rings, would ever wear in to mate with cylinder walls.

 

[Auto tech]

boomers to me is more or less anyone born before like 1980. That or they have the same mentality as someone born in 1920.

Gen x is from late 60s up until 1982. Like me

 

[RDY4WAR]

Myth. Like many other myths, it started due to people making conclusions about things they have never studied, have no experience in, and blinded by irrelevant pre-conceived notions. Data is only as valuable and accurate as the knowledge of the observer, which is why anecdotes are wrong >80% of the time.

What I recall hearing was that you didn't want to break in your new engine using synthetic oil.

This one had some merit but not for the reasons many believed. It wasn't due to it being too "slick" but rather because the additive response was better in group I and II conventional base oils, promoting better ZDDP reactivity at colder temperatures. That's no longer the case as research in group III base oils is showing better additive response than group I and II. Thus, we're starting to see dedicated break-in oils made with group III base oil. You still don't want to use group IV PAO due to the low solubility and group V ester and AN due to competition with ZDDP at high concentrations.

 

[Dimitrius James]

I remember “the molecules are so small they go past the seals”

This is what I remember as well. A lot of cars in the 1980's and prior had cork valve cover and oil pan gaskets. They said not to use a synth if you had those as the small molecules would make their way through any cracks in the gaskets lol.

 

[Dimitrius James]

But they had Slick 50 back then

Let's not forget Dura Lube. The way that stuff was marketed it could fix anything. They practically stopped short of calling if an elixir.