Do Esters and PAO's deteriorate/interact with plastic engine internals?

Z

zfasts03

Joined
Jul 21, 2008
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Phila, PA
Do the higher percentage of esters and PAO's found in higher end oils shorten the life of internal plastic engine components, such as timing chain guides, plastic valve covers, oil pans, seals gaskets etc.?

I remember having a plastic funnel I used for drain oil that got brittle and cracked from contact with these oils.

Also, does the higher esters content attract moisture more so and should be avoided if the vehicle is short tripped or in a humid climate? and would the engine be better off with a cheaper oil changed more frequently?
 
zfasts03 said:
Do the higher percentage of esters and PAO's found in higher end oils shorten the life of internal plastic engine components, such as timing chain guides, plastic valve covers, oil pans, seals gaskets etc.?

I remember having a plastic funnel I used for drain oil that got brittle and cracked from contact with these oils.

Also, does the higher esters content attract moisture more so and should be avoided if the vehicle is short tripped or in a humid climate? and would the engine be better off with a cheaper oil changed more frequently?
Click to expand...
Calling @Foxtrot08 for the inside scoop…

In my amateur opinion, esters can affect seals, but this is offset with other components in the oil. If you’ve got a fully-formulated oil, there shouldn’t be any issues.

If you go playing backyard chemist with all kinds of additives and snake oils, the risk likely increases for seal & plastic damage, but how much it increases risk I have no clue. I’ve personally never had an issue.
 
When plastic timing chain guides and tensioner guides, crack and fall apart, Is this a result of poor design/inferior parts, age or was it an oil that didn't play well with the materials these components where made of?

I see engine disassembly videos on YouTube and many time these timing chain components are broken.
 
plastic gets old and brittle.. its heat cycled etc etc. how long is it supposed to last?
Personally I dont think you are going in the right direction.
A fully formulated motor oil is compatible.
I'd be more worried about dufus's who constantly add random additives because
"OIL ALONE IS NOT ENOUGH" to their 25 year old civic.
Man the 45hp from these stickers is extra hard on the bearings
we need LUCAS unadditized bright stock that will save those rings! (/sarcasm)

LUCAS THE EXTRA PROTECTION NEEDED IN FOUR CYLINDER ENGINES!
1700688261492.png
 
Last edited:
SubieRubyRoo said:
Calling @Foxtrot08 for the inside scoop…

In my amateur opinion, esters can affect seals, but this is offset with other components in the oil. If you’ve got a fully-formulated oil, there shouldn’t be any issues.

If you go playing backyard chemist with all kinds of additives and snake oils, the risk likely increases for seal & plastic damage, but how much it increases risk I have no clue. I’ve personally never had an issue.
Click to expand...


Absolutely, base oils play havoc with plastics. There is a whole section of the CLS test about compatibility of seal types and polymers.

Real life situation, an OEM was having excessive warranty issues with transmission lines. They were using a TES 295 product, as TES 668 came into licensing and replaced TES 295.

Hundreds of thousands of dollars in testing later, significant volumes of old TES 295 product found for the OEM… and the leak/warranty issue still continued… the part supplier admitted to changing the polymer compound in the line. The production lines were a different polymer make up than the sample/test products.

But yeah, there’s compatibility issues out there. For sure.

In a standard Automotive engine, assuming new production/newer production (last 20? 30? Years.) There *should* be no compatibility issues.

Should. Should is the key word.

It doesn’t mean the production world is perfect. Things get over looked. Corners get cut. Aka, **** happens. Large production manufacturing is hard.
 
Foxtrot08 said:
Absolutely, base oils play havoc with plastics. There is a whole section of the CLS test about compatibility of seal types and polymers.

Real life situation, an OEM was having excessive warranty issues with transmission lines. They were using a TES 295 product, as TES 668 came into licensing and replaced TES 295.

Hundreds of thousands of dollars in testing lasted, significant volumes of old TES 295 product found for the OEM… and the leak/warranty issue still continued… the part supplier admitted to changing the polymer compound in the line. The production lines were a different polymer make up than the sample/test products.

But yeah, there’s compatibility issues out there. For sure.

In a standard Automotive engine, assuming new production/newer production (last 20? 30? Years.) There *should* be no compatibility issues.

Should. Should is the key word.

It doesn’t mean the production world is perfect. Things get over looked. Corners get cut. Aka, **** happens. Large production manufacturing is hard.
Click to expand...
Do you know of any base oils that have higher failure rates with plastics? I’m sure that info is held pretty close to the vest, but it would be good info. Thanks for chiming in!
 
SubieRubyRoo said:
Do you know of any base oils that have higher failure rates with plastics? I’m sure that info is held pretty close to the vest, but it would be good info. Thanks for chiming in!
Click to expand...

Synthetic esters have the biggest compatibility issues. The choices of acids and alcohols, used to produce the esters, has a lot to do with their solvency and compatibility.

Honestly a little out of my wheelhouse, when it comes to actually producing the esters. I know enough to be dangerous about the subject. I’m imagining all(?) synthetic esters used in automotive lubricants should be compatible with automotive polymers.

But then you have the time & temperature situation. This dives more into chemistry of plastics than I know about to talk with any certainty. However, it’s my understanding that with time and heat, plastics can be affected by oils. Whether it’s oils impregnating the plastics, or oils drawing out the components from the plastics. Heat essentially speeds this process up and can help remove the “resistance” to the oil.

I sat through a long webinar on this issue a looooong time ago. But I’ve also killed a significant amount of brain cells between then and now. I’m sure molakule can correct me or clarify more.

I do know you see significantly more compatibility issues in industrial synthetic lubricants. As seals and gaskets can be made out of a whole plethora of materials, from any age in the last 100 years. Where as at least in the automotive world they’ve worked on standardizing things.
 
The question the OP poses is way more complex than a simple post here will explain past the following:

Much of this centers around use of the word "plastics". That word is no different than the dreaded use of the word "synthetic" oil. Asking about "plastics" is not nearly definitive enough to reasonably give an answer. "Plastic" is just a term we use very loosely for a slew of classes of chemical compound materials which have a broad range of applicability, and concerns. Nearly all "plastics" have some elements or compounds they react to, and yet they can be immune to others.

This same problem with poor descriptions occurs when people ask about hose. Check this out as an example of how many compatibility pros and cons exist, depending upon what "hose" material is present:
www.tubes-international.com

Table of hose material chemical resistance - Tubes International

PDF – TABLE OF HOSE MATERIAL CHEMICAL RESISTANCE
www.tubes-international.com www.tubes-international.com

Here's another example of how complex chemical compatibility can be.



If the OP wants to know which oil bases react with something, he's going to have to be a LOT more specific about a "plastic" engine part. There is absolutely no way anyone can give a decent answer when the question is so poorly posed.
 
Not sure if the question is as unclear as it seems to be made ( I'm not chemist).
What possible "plastic" components of the engine can be in contact with engine oil?

Oil pan, valve covers, chain cover and guides etc.
I don't know if anyone can ( maybe someone has the knowledge) be sure of "plastic composition" of said parts.
 
Rand said:
plastic gets old and brittle.. its heat cycled etc etc. how long is it supposed to last?
Personally I dont think you are going in the right direction.
A fully formulated motor oil is compatible.
I'd be more worried about dufus's who constantly add random additives because
"OIL ALONE IS NOT ENOUGH" to their 25 year old civic.
Man the 45hp from these stickers is extra hard on the bearings
we need LUCAS unadditized bright stock that will save those rings! (/sarcasm)

LUCAS THE EXTRA PROTECTION NEEDED IN FOUR CYLINDER ENGINES!
View attachment 189797
Click to expand...
The plural of "dufus" is "dufuses" or "dufi." It can also be spelled "doofus." (y)
 
Well, I’ll tell you that oil bottles don’t seem to have a problem with oil. Just used some Redline MTL in my Mazda and the bottle had been in my basement for 8 years and seemed good as new. I suspect it depends on the polymer and plasticizers used. One would hope automotive engineers chose plastics compatible with their environment.
 
SubieRubyRoo said:
Calling @Foxtrot08 for the inside scoop…

In my amateur opinion, esters can affect seals, but this is offset with other components in the oil. If you’ve got a fully-formulated oil, there shouldn’t be any issues.

If you go playing backyard chemist with all kinds of additives and snake oils, the risk likely increases for seal & plastic damage, but how much it increases risk I have no clue. I’ve personally never had an issue.
Click to expand...
Leave my MoS2 out of this 🤣🤣🤣
 
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