What Weight Oil Should I use in a 1976 Ford F-250

[ozzmann]

This is a 1976 F-250 with a 390 engine with 81,000 original miles. It leaks a little
oil, but this is to be expected. Should I use a 10w-40 or straight 40. Any help would be appreciated .

 

[addyguy]

15W-40 or 5W-40 HDEO.

Pics of truck?

 

[lexus114]

A 76 with a 390?? You sure thats the original motor?

 

[Rob_Roy]

Given the mileage and your climate, 15w40 would be my first choice for a year-round oil.

It is common for these engines to have low oil pressure at a hot-idle, 10-15 psi if I remember correctly.

Originally Posted By: lexus114
A 76 with a 390?? You sure thats the original motor?


A 390 was available for '76, at least according to old parts books and wikipedia: http://en.wikipedia.org/wiki/Ford_F-Series_sixth_generation

 

[lexus114]

Originally Posted By: Rob_Roy
Given the mileage and your climate, 15w40 would be my first choice for a year-round oil.

It is common for these engines to have low oil pressure at a hot-idle, 10-15 psi if I remember correctly.

Originally Posted By: lexus114
A 76 with a 390?? You sure thats the original motor?


A 390 was available for '76, at least according to old parts books and wikipedia: http://en.wikipedia.org/wiki/Ford_F-Series_sixth_generation



Oh, Okay. I didnt realize that.

 

[Chris142]

Yes the HDDo is a good idea. Those FE's ate cams and lifters.

 

[brentalan]

10W-40, 15W-40, 5W-40 are all fine. I wouldn't recommend straight 40.

 

[WMSmotorhead]

With the type of cams in there, it would be wise to use something very rich in ZDDP am I correct?

 

[TallPaul]

Yeah, HDEO is in order for it's higher levels of zddp or use a good zddp additive. You probably can run 10w30 depending on what your owner manual recommends and how the oil pressure is. Nice truck!

 

[Bgallagher]

Originally Posted By: brentalan
10W-40, 15W-40, 5W-40 are all fine. I wouldn't recommend straight 40.


+1 I say use QS Defy 10w-40. It's rated SN and has a boost of zinc that would be nice for that engine. Plus its a semi syn.

 

[Oil Changer]

Look at my bottom signature line.

 

[TFB1]

Originally Posted By: lexus114
A 76 with a 390?? You sure thats the original motor?

From '73, the 360 & 390 were the most commonly found V8 in the F series through '76..

The 390 was discontinued in the full size car line during '71(repl with 400), Mustang & Torino lost them after '69...

 

[mechtech2]

A 15-40 would be great. It is called a Heavy Duty Engine Oil -HDEO.
A bit thick for cold winter starts up North, but your engine should do very well on it there.

 

[67lemans]

An HDEO in either 5w40, 10w30, or 15w40 is what I run in my 77. I use the 5w or 10w in the cooler months

 

[artificialist]

You might be able to reduce leakage if you used a high mileage engine oil.