calimagsr

My 5.4 has 250000 miles on it. Would it hurt to go to synthetic oil.

02_Black_On_White

NO you do not need to switch, at 250k why change it up? Full synthetic oil has harsh detergents that can over clean the inside of your engine and clog the oil pickup screen and literally you'll grenade that motor. Unless the motor has been gone through would I say it would be okay otherwise hell no. I switch to full synthetic at 80k and haven't had any issues

MCpllabelle

Mines been running synthetic since it was born...no issues.

02_Black_On_White

That's different than switching at 250k it is NOT advised. Synthetic is a whole different animal than dino oils.

blupupher

iTrader: (2)

Switch away without worry, but there is no point. You have gotten this far on whatever you have done, so keep doing it.

It is more important to use a quality oil that is speced for the engine and change it when needed vs what type of oil you use.

MCpllabelle

Agreed! I was simply saying that.

Carcrazygts2

I run synthetic, But Mine has been Synthetic since 60k. It is not recommended to switch to a full synthetic with high mileage.

MCpllabelle

I did hear about someone here in this area who swapped and his engine started to burn oil.

02_Black_On_White

That is completely wrong. If he switches to full synthetic at 250k he has everything to worry about. Those deposits coming off from harsh detergent have to go some where. Straight to the pick up screen.

BlakeA

With mileage that high I'd be iffy if it's used regular oil all its life. However Motorcraft oil is a synthetic blend and something like that should be fine.