who is using 5w-20 and who is using 5w30?

40th GT said:
I've been using 5w-20 all along and I will for a long while but I have to ask you this: If the bearing clearances did get tighter, why do you think that Ford never addressed it in the TSB regarding the oil weight change? (or have they??) Because if they have addressed it, I think that more people would be running 5w20 right now instead of anything else.

To my knowledge it never was adressed. I think they just assumed for people to use what it says clear as day on the cap.
 
I think the fact that they write it on the oil filler cap is just a liability type thing. That way, if somebody switches to SAE 70 and blows it up or something, Ford can point to the cap and say "Says right there.. sorry."

I don't think any vehicle I've ever owned had it written on the cap until I bought my foxbody. And I also don't recall a single vehicle I've owned where I ran the exact manufacturer recommended viscosity the entire time I owned it. Bearings wear, tolerances change.. it's a fact of life when you are talking about moving parts over time. If you aren't running 5w30 yet, you probably will need to some day.. so why fret over it? If you're in the warranty period, run 5w20, if not, run whatever you want.
 
i've been using 5w-30 since i've had the car. it worked just fine and it got plenty hot here in the summer. just went to Advanced Auto and for some reason got 5w-20. will this affect anything? it is starting to get pretty cold around here, so it wont be long before winter hits us square in the ass. any problems if i use the 5w-20 even though i've been using 5w-30?
 
Sncbluegt said:
Actuall if the oil cap says 5w-20 on it then it is very wise to use what it says.
1. when they changed over to 5w-20 the bearing clearances were closed a little and it takes a thinner oil to get around to all the journal.
2. it has to be thin to properly lubricate the overhead cams when cold.
I have worked at two Ford dealerships for almost a year and a half combined. I have seen three engines with spun bearings. We couldn't understand why, head gasket good, intake gaskets good, proper maintenance, grandma driving, BAM 5w-30 was put in the motor.

IMO anything but 5w-20 is playing fire with a expensive engine.

They changed to 5W20 In 2000 or 2001. 1999 had the same motor and it was 5w30. It was changed to 5w20 for CAFE. That tighter tolerance stuff is crap. If that was the case a crap load of Mustangs will have spun rod bearing problems.
 
20 weight is WAY too thin for hot weather, don't care what ford says.

Engine has not changed at all, 20w is for MPG only.

I run FULL Syn Motorcraft 5w-30 oil with a Lawyer standing by.
LOVE to see them void my warrenty for using 30w oil instead of 20w.

Like the book says RECAMENDED oil weight.

My engines sounded like hell in traffic with 20w oil and 100 degree weather.................
 
Cavallo said:
20 weight is WAY too thin for hot weather, don't care what ford says.

Engine has not changed at all, 20w is for MPG only.

I run FULL Syn Motorcraft 5w-30 oil with a Lawyer standing by.
LOVE to see them void my warrenty for using 30w oil instead of 20w.

Like the book says RECAMENDED oil weight.

My engines sounded like hell in traffic with 20w oil and 100 degree weather.................


true, but in colder winter conditions its just fine
 
I've been using Mobil 1 5w40 full synthetic ever since I added the nitrous. I figgered my stock short block could use a little more hi-temp bearing protection. I'm pushing the stock bottom end to the limit so I thought ever little bit helps:nice:



Jay
 
Cavallo said:
20 weight is WAY too thin for hot weather, don't care what ford says.

I respectfully disagree with that statement.

I am however interested in some numbers for your side of the argument, if by chance you could provide them.

I watched my autometer gauge, and saw 25-30 psi at hot idle (probably more like 28) at full operating temp on a 100+ degree day here this summer. What is your psi at hot idle with 30w?