Oil Seal Life vs Oil Grade Study

[twX]

Since the thick vs thin debates here have been getting stale, I thought I'd add another point of contention to the mix. Here's a study SAE 2007-01-3539 that concludes that thicker grades of oil are worse for the durability of crankshaft seals. I haven't been able to find any other studies that have attempted to replicate this result.

Seals after 2160 hour torture test at 6,000 rpm with oil at 150 C:

(photos and direct full link removed- Mod)

 

[xpeteyjtx]

very interesting! I did not read the article… appears to be subscription based. Sounds like there is correlational between seal wear and oil viscosity. Makes physical sense to me. I’m glad I went down to a 0w20 from 5w30 for the cold months! Better seal life!

 

[LongTime_Lurker]

Most people will not subject their seals to that level of abuse but this is interesting nonetheless.

 

[oldhp]

2160 hours. Hmmm........ 6000RPM. Hmmm......... 150C / 302F Hmmm......... With that info I would like to know what engine, dyno or whatever could do that. I'd like to see same hours at 1800RPM with oil temp at 100C / 212F because this is where most engines live at on the road. I can't see hardly any difference day to day around town driving.

 

[nobb]

It makes sense, but there's so many other variables that go into seal life that I'm not entirely sure how much practical difference this makes.

For example, heat is probably the most important variable. When I was doing my timing belt and changing the camshaft and crankshaft seals, I noticed the crankshaft seal was noticeably more brittle and had changed to a darker color. The mere presence of that seal being deeper down on the engine bay where it was running hotter made a huge difference.