I have Rotella 10w30 in my '95 Bronco's 302 currently. It is due up for a change and I am thinking of dropping in Motorcraft 5w20 semisynthetic. I have run 5w20 in another car - 3.0 Taurus - with outstanding results according to 2 Blackstone UOA samples. I'm in Chicago and we've already seen single digits this winter and I'm sure we'll see even lower in the next two months. The truck does several short trips during the day and usually never gets really good and hot.

I know that Ford back-spec'd the 5w20 a lot of engines into the 90's and was wondering if anyone else here is using it in a 302. What has your experience (key word, there ) been?

Calvin

 

I don't think you will notice much of a difference in engine performance. While my 302 engine isn't finished yet (just gonna get 10w30), my car sees 5W30 all year round with temps from -35'C to +30'C. The only vehicles in my family that get different grades of oil are the diesels. The tractors get 0W40 and my dad's VW diesel gets 0W30 instead of 15w40 (15w40 doesn't move in cold weather). Just the VW doesn't quite like the semi synthetic as it slowly burns it.

If you want long engine life just use a quality oil and filter with regularly scheduled oil changes. My family and other people I know have had great luck with this. Our 87 Pathfinder went 767 000 kms (sold to neighbour and it's till going) and my dad's VW has 550 000 kms. I personally don't put much faith in oil tests.

 

Ford did back spec it for the 302. I would run it for about 2000 miles and do a UOA on it. I run the 5w20 in a stationary load governed 391FT powered water pump. I posted the UOA results last year the wear was only 11PPM FE on a 175 hour run. The lead was single digit.

 

stick with the oil you are using. 5w30 will actually cause some valve train noise at startup

 

I would think the 5w20 would be excellent for the short trips in winter, and switch back to a 10w30 (or straight 30 weight) when the weather warms up.

 

That's my plan. I have the 5w20 in as of Saturday and will switch back to 10w30 in April when the next change is due.

I took it for a short spin and didn't notice anything different in noise or performance. It's supposed to get back below zero by the weekend so I'll no if the thinner startup is making a difference.

Calvin

 

I'm happy I live in Texas, I run Straight 50 weight in the Summer. Haha. During the winter I run 20/50

 

I run 10W30 year round in my 302... Some of my friends run 5W40 in there chebbys... But i find 10W30 Esso is perfect for out here....