Are Ester based synthetics harmful to old seals?

[FCD]

Some of you might have read other of my posts where i ramble about what oils i could try for my next oil change well i've stumbled upon Motul 7100 4T 20w50 which is a synthetic ester based motorcycle oil , do you think this would be harmful to the seals on a 40 year old car like mine? Despite being a 20w50 will it just start [censored] out the rear and front main seals like i've read on other forums?

 

[Atesz792]

Knowing the price, I'd first ask if this oil is necessary in a 40 year old daily driver? I think not, your money would be better spent taking your GF to the movies.

 

[andrewp1998]

Try high mileage like syn maxlife or `any other ones.

 

[Trav]

some of these "true" synthetics were responsible for the fears that still exist today. Yes they can and do cause old seals to leak and sometimes badly enough to need a tear down to replace all the seals in the engine.

These old seals were nitrile or neoprene (many seals still use these materials) they are not compatible with esters. Oddly enough the older cars that used rope graphite seals don't seem to have a problem with esters.
In small amounts it can "condition" seals, a little more and it can swell them and stop leaks but its usually short term, many times the leak returns with a vengeance.

Modern engine oil formulations take this into consideration but some specialty oils may not, some of these oils are short run oils and the engines use seal materials compatible with esters (FFKM = big $$$).
Unless you know what seal materials are used I would stay clear of these oils and additives that contain larger amounts of esters.

http://mykin.com/rubber-chemical-resistance-chart-3

http://www.sealanddesign.com/category/Rubber-Material-FFKM/591.html

 

[FCD]

Trav so i'm better off with a non Ester Synthetic like Mobil 1 or a high quality conventional like Valvoline VR1
Andrew we don't have Valvoline Max Life or HM here i can only get VR1
Atesz, i don't have to worry about taking my Girlfriend out because i have none! also my Capri is not a daily driver

 

[Trav]

I would use an HDEO dino oil in hat old school flat tappet cam engine. No point in tempting fate IMO.

 

[FCD]

I do that already i run Shell Hx3 High Mileage oil with 1200ppm of zddp and i wil use Valvoline VR1 next time which has 1300ppm

 

[zeng]

Originally Posted By: FordCapriDriver
I do that already i run Shell Hx3 High Mileage oil with 1200ppm of zddp and i wil use Valvoline VR1 next time which has 1300ppm


I'm afraid Trav is referring to dual rated HDEO's CI4/SL or CJ4/SM, excluding HX3/5.

 

[FCD]

I'm not sure i quite understand what you're saying HX3 Is dual Rated , SL and CJ-4

 

[Rand]

Originally Posted By: FordCapriDriver
I'm not sure i quite understand what you're saying HX3 Is dual Rated , SL and CJ-4


can you post a link or a picture? I'm showing

SL/CF

 

[zeng]

Originally Posted By: FordCapriDriver
I'm not sure i quite understand what you're saying HX3 Is dual Rated , SL and CJ-4


No, HX3 isn't dual rated HDEO , as far as I understand.

 

[FCD]

"For Diesel and Gasoline engines"

 

[Trav]

That's fine for that engine in that climate.

 

[Pontual]

Leaks occured more when the syn base was pure PAO. They started to add esters to help the seals, by not letting shrinkage. Since PAO shrinks, the esters make them swell. What Most seal conditioners do is swelling.

 

[Popsy]

My Barchetta is only 20 years old but not leaking a drop with Motul 300V (not so sure about ester in it). TBH many seals appear to be recent, or they were exceptionnal quality from factory.
I don't know about base oils in Shell Rimula (probably gr. III and/or gtl) but my Marea (a 18yo youngster) is leaking less with it than with SHU 5W40 (gtl). Not trying 300V in it, for sure.

Next week I'm going to San Sebastian, I can buy you some 15W50 300V if you feel like trying it. Last time I checked it was 24€/2L at the local supermarket.

 

[FCD]

Haha no need to thanks , San Sebastian is over 500 Km away from me!

 

[Popsy]

And like 900Km away from me, that's the best I can do, lol!