Hey guys, I'm new here, I think this is the right forum for this, but feel free to give me the boot if it isn't. But I've got a question for ya'll.
About two months ago I got a 1981 F100 stepside, and I want to go ahead and do an oil change soon, but I've looked all over the interwebz, and can't find what kind of oil I should use. Does it really matter too much, or should I just use a basic intermediate kind like 10w30?
Thanks guys, Stephen.
If I can figure it out (gimme a few minutes) I'll post a pic or two of the truck, cuz I know everybody loves looking at a truck.
Welcome to the forum, that's a nice looking truck. I use Motorcraft Syn-blend 5w20. On my next oil change I am thinking about using the synthetic Rotella T. And as always a FL1A Motorcraft oil filter. But, you can always use whichever oil and filter that works best for you.
I wouldn't use synthetics at ALL on a motor broke in and run for over 50K+ miles on conventional Dino oil. It might work just fine and all, but the typical rule of thumb is to break in a new motor with Dino oil then switch to synthetic and run that the rest of it's life. If it has been on Dino oil its whole life, keep it on Dino oil. Just keep up with your oil changes and you should be just fine for the life of the truck.
If I remember right, on our straight-6's, the factory oil viscosity is 10W30. I put 10W40 Valvoline dino oil in mine. Do not use a Fram filter. Use a Purolator or a Motorcraft (or equivalent). Find one that has the check valve in it to keep the motor oil up in the motor as well. It helps keep oil up in the motor after it's shut of so it's easier on wear and tear whenever you crank it back up.
I've heard quite a few people say on high mileage motors (200K+) that they use and recommend heavier weight oils to keep up the lubricity. A relative of mine has a Dodge Ram nearing 200K and he uses 20W50 in his and doesn't burn a drop of oil. Oil pressure is good. He's also an old school drag racer, and he also recommends keeping synthetic out of a motor run on dino oil its whole life.
Like was stated, it's all preference, but that's my $0.02.
But yes, stay away from anything lower than 10W30. That's too low weight.
Yes, if your motor has a lot of wear, a 10w-50 or even a 20w-50 will make up for the differences in clearances due to wear. If your vehicle starts to behave like it's burning a little oil, switching to a heavier viscosity will help with that issue.
Also one thing I forgot to mention, you should use an oil that has higher ZDDP, or zinc. As the newer oils rated SM or higher have dropped their amount of ZDDP due to emissions reasons. Those newer oils tend to harm older engines because of the lack of ZDDP. Newer oils tend to be low in ZDDP.
I have an 80 with a 302. Ive put nothing but Rotella 10W40 in since i bought it. I remember choosing it bc I was told it has a bit higher zinc content for those lifters, but who knows. Either way it has worked well for me, just have to make sure Im a bit more warmed up in the winter.
there are some very good resources on this forum about oils but like several have said already, stick with conventional 10w 30 if that is what its been running on. STAY AWAY FROM PENSOIL!!! anything coming from a shell or mobile 1 refinery are pretty good. before i swapped in a new 300-6 my old one needed 15w-40 rotella to keep the main bearings lubed.