I have a 1986 f150 Lariot 5.0 302. I know it is a lot of opinion but I want to know what all of you guys think is the best oil to use in this engine with about 117,000 miles. Please give your opinion and back it up with why you have made your decision. I am thinking about going with Mobil 1 once I get done with the Auto-RX treatment.

 

The important thing is not the oil, but changing it often. The by products of combustion are water vapor. That plus the fuel that gets by the rings sits in the oil and forms a sludge and acid that eats at the bearings. All modern oils have detergents to pick this stuff up and not let it settle in the engine. So when the oil is changed, these contaminents are also removed from the engine.

 

Franklin's absolutely right.
Ask yourself how many times you've heard "oh that truck died cause they used X brand of oil in the engine"? Never.

 

I have come close to saying that. I have used Pennzoil, Quaker state all with no problems. I run Mobil 1 now in all my vehicles but....

I can't say for sure it was the oil but I had a car that specifically called for Castrol GTX ( an old Triumph ). So I ran that in it and figured what the heck and bought it by the case thus using it also in a GM with a 3.5 engine that is known for being a good motor. Within a year, both cars blew the engines. The Triumph had a piston rod disintegrate and the GM slipped a crank bearing.

It could have been bad luck or whatever but I have never blown a motor on any other oil.

I like the ideas of synthetic, especially the durability when driving on long trips as there have been arguments about regular oil thinning. ( I have read that some think you should run 10-40 instead of 10-30 if you are doing a cross country drive because they claim the oil thins during extended drives like that)

My only warning on synthetic is that my truck engine doesn't use or leak at all with Pennzoil. It is dry as a bone. WHen I use Mobil 1, it leaks a couple drops by the rear main seal over night. Not bad but enough to see on the pan where there is a small droplet. I even switched back to Pennzoil and it stopped and stayed dry again. Put the Mobil 1 back in and it started leaking again.

I have read older engines can have leak problems or use oil when using synthetics as synthetics act thinner but give the same protection.

Don't know for sure as some people treat oil brands like a religion and argue their cases well. Some claim that one region of oil is better than others based on ash content and I can't recall off the top of my head which is which. I may be wrong but I think that they claim that Pennsylvania oils have more ash than Texas region oils. I don't care as I figure the filtering and processing probably make the two equal but who knows for sure.

Anyway, thought I would chime in. What ever you use, I agree with the others, change it often, use a good filter and I will add that I hate additives.

I recall racing as a teen when slick-50 first came out. Every one ran out and started using it. My friends race car had a competition filter that didn't have a bypass in it. He tried slick-50 for the first time and by the time he went from the pit to the starting line he lost all oil pressure. We took that filter off and it was clogged with the most disgusting goo you ever saw. Most of that junk just clogs filters, opens the bypass on a normal filter and then you aren't getting any filtering at all until you change your oil again. Normal oil works fine. Don't mess it up. Think about it, anything that is stopping a leak and is likely also clogging oil ports in your motor. Anything that is making it slicker or better must have already been thought of by oil makers as they spend billions on research.

Good Luck,

Lee

 

We I a Qstate guy i have got 200000 + miles no motors with no issue.But about any of the big name oils is good . Iknow everyone has the best. I have seen dirty motors with pennzoil ,mobil , you name it If you want things to last change that oil every 3000-3500
I know of trucks with 300000 that just had small stuff fixed and they are still going.The only thing I have had in shop is motors with synthetics. A couple of these truck the owner were really up on repairs and changes but I have replaced 3 motors with around 120000 miles that ran synth. I know they go at any time but 150000 is norm . I don't know if the use of synth after so many miles leads to this or what. But I don't run it in any of my motors.

 

Hmmm..fellers there's a lot to think about here and the best thought is to change oil often. (at most every 3500/4000mi.) Personally I'm still trying to figger out why the price of a barrel of crude oil/gasoline has gone sky high and yet oil by the quart remains about the same as it did in 1980. Go figger..eh? Some other thoughts; next time you're in WalMart check out the oil prices and also look at the SAE ratings on the containers regardless of brand. Not just the oil weight mind you..the SAE rating. That's the little letters alongside the oil weight. Letters like SE/SJ/ etc. etc. Now do a Google search on the meaning of those letters. Somewhere I have a printout of just that topic...unfortunatly can't find it right now. If anyone has an old copy of Motorcycle Consumer News mebbe they can share with us their findings on the ratings. They listed ash content and additives/pros and cons. It was a real eye-opener! Now, before you leave WalMart read the SAE ratings on their SuperTech Brand of oil. I've used Castrol, Pennzoil, WolfsHead, QuakerState and many off-brands. I have never had, nor seen, an oil breakdown related problem. Ever. I do have a question. I have been advised to use only Ford oil filters on Ford products due to the alledged "oil-bypass" feature on them. Is this just hype or fact. I generally use Fram filters. They're available eveywhere and relativley cheap. As far as synthetic oils, the main selling objective seems to be 25,000 miles between oil changes. Not gonna happen with my truck! JMHO. Audie..the longwinded one. P.S. just changed oil today in my '86 F-150/302/4X4...Ford Motor Company..I have a bone to pick with you!

 

http://new.api.org/aboutoilgas/motoroil/index.cfm
http://new.api.org/certifications/en...lGuide2006.pdf

 

someone metioned the problem of old engines leaking with synthetic, this is apperently caused by the oil cleaning out the seals and causing small leaks. with time they claim the additves in synthetic will condition the seals stopping the leaks. There are a few posts on the oil and luberication board about using blends or high mileage oil to ready the motor for the use of full synthetic, maybe this is a good option instead of going strait to full synthetic?

 

Thank you all sooooo much! I have heard so much on this subject but never when talking about old trucks. I believe that during the break in period on a new car you should use conventional oil. Once you break it in good switch over to synthetic as it keeps your engine clean and you can drive on it longer without the breakdown. I would still change at least every 5000 miles cuz my dad says if the filter is full it doesn’t matter how good your oil is. I am gonna look at all the info you guys posted and make the most educated guess. I think I am gonna go with a good quality conventional and change every 3000-4000 miles. I don’t know how many people thank you around here, but I want you to know that I really appreciate your input. I am 32 years young and am finally seeing that I still don’t know s**t….ha ha!

 

Everything you *ever* wanted to know about oil:

http://www.boss302.com/oil.htm

 

Yea, Wal-mart Super Tech!

 

Boo, Castrol!