Ford's 5w30 to 5w20

[FoxBodyNick]

Don't really care if its ass backwards, it's worked for many modular motors in my family with 100k+ miles on them without issue, some are getting close to 200k miles.

I believe he is referring to the 10w-40 being "thin" in comparison to 5w-20. Not on whether it worked or not. Unless you were meaning not wanting to go 5w-20 thin on modular...

[03trubluGT]

I think they stopped using adhesive on the gasket. It comes off very easy.

Just be sure to always check I guess.

I always clean off the filter mounting surface with a paper towel, this way I can tell if there is a gasket stuck to it.

[shumpertdavid]

Crapstang, there is nothing wrong with running the 5w-20. Ford switched to 20 weight for fuel economy. I always run 5w-30 synthetic in ALL of my cars, I would rather have an extra protection over extra fuel mileage, however minuscule either of them may be.

On anything that doesn't have variable valve timing straying from the recommend oil weight doesn't pose huge risks as long as you don't get something like 20w\50.

ON ANYTHING with VARIABLE VALVE TIMING, changing from the recommended weight can cause running problems, check engine lights, valvetrain noise, etc. Also, if you don't do routine oil changes, the deposits will clog the small oil orifices in the tensioners and the vvt solenoids causing issues.

[91CoupeMike]

5w50 is fine, it's still 5w oil either way. Anything 5w will be just fine.