Hey all

I have a 1990 F-150 4.9L 4x4 with 154,000 miles on it. I havent had it long but I know that the fella who I bought it from used Havoline 10W-30.

I was wondering what you all thought about switching to synthetic oil. Is it a good idea? What are the pros/cons. What is the best type to use?

I have never used any type of synthetic oil before.

Thanks

Matt

 

I've heard using synthetic on higher mileage motors is not a good idea. Also not good for brand new motors (break in issues).
If I find where I read that I will post it. It was a very insightful article.

 

pros: longer change intervals, higher resistance to heat, less wear on parts, resistance to breakdown of the oil

cons: spendy, has a tendency to leak out of older engines

someone told me it may affect fuel milage if the car runs at a lower temperature than it was engineered to (better lubrication)

But that might be a total lie.

Mobil 1 seems to be the oil of choice among my friends.


My oil of choice for my truck is whatever is on sale for under a buck a quart.

- -

 

Personally, I run the Valvoline MaxLife(usually 10-40) in the F250 with 126k and a 88 Blazer with 268k original miles. I don't know what the real advantages are on synthetic, but I can tell you is that regular oil changes make all the difference. I don't care if you run dino oil or synthetic, if you don't change it regularly(not every other year), but between 3-5k, you should be fine.

 

Yes, synthetic in a higher mileage motor isnt the best idea. Currently, I have a 460 that turned 200K miles a year ago, and its lived on 20w-50 its whole life. Older motors with worn in parts like a heavier viscosity oil. If you plan on owning this truck for a long time (ie. new motor at some point), you might consider synthetic after 9K miles or so on it. Always break a motor in with regular oil. I run Castrol or Valvoline for regular motor oil, and Mobil 1 for synthetic. My bronco has Mobil 1 in it now. AFAIK, Mobil 1 is the best synthetic you can buy. Its the motor oil that all Chevrolet Corvettes, all Porsches, Mercedes-Benz AMG models, Dodge Viper, Ford Mustang Cobra R and all Aston Martin cars leave the factory with.

Rich

 

If vettes, mustangs..... all roll off the assembly line with mobil 1 synthetic why is it a good idea to only consider synthetic after 9k miles or so. You would think that the engineers of these cars have done thier homework and if it is good enough for a vette..... it is good enough for anything else. My old volvo runs synthetic (amsoil) just fine. Synthetic oils do clean your motor out so after a while any gunk that was crammed into the nooks & cranys plugging little leaks will be removed causing your motor to leak a little oil.

 

OK then, what about some of these extended life oils? I have seen that Quaker State oil made specifically for 4x4's. Anyone have experience or insight with those?

I do plan to keep the truck for a long time and I want to make sure that I use the best oil in it.

Matt

 

I have a 1991 F150 with over 192,000 miles on it. I switched to synthetic oil after it had well over 100,000 on the truck. I also used Havoline 10W-30 before the switch. So far so good. Although I can't really prove it I think it made some difference in performance. I also have synthetic fluid in the differential. The only leaks I have I had before the switch. Very slight around the pan and a tiny bit around the distributor. My truck uses less than a half a quart at 3000 miles. I bought the truck used with 73,000 and change on the odometer. Mine is a 4.9 I6 as well, forgot to mention that. However I do change my oil regularly but at about 5000 miles. So good bad or otherwise, it is working for me so far. My choice of oil is Royal Purple. Why, well because I wanted to see if it was really purple, it is, and I have just stuck with it. If not that, Mobile 1 for sure. My only suggestion, use a top quality filter no matter what you use.

Mike

 

I think once the rings get properly seated, you should be able to run synthetic just fine. Last race motor we broke in, we ran straight 30 weight cheap oil in it for 2 or 3 heat/cool cycles, then drained it and refilled it with mobil 1. I think 500 miles or so and you should be safe. I would be cautious switching to synthetic on older motors. I also wouldn't buy quaker state, I've seen a couple motors that ran quaker state, and they were full of sludge.

 

I use syn in all my engines, but that is from the start. An engine with as many miles as yours probably won't benefit a lot from syn. Synthetic is supposed to prevent wear and varnishing in engines over the long haul. Yours has already made the long haul, and whatever wear and varnish you would have is already there.

Syn sometimes will wash away the grease and oil that plugs up any leaks you have so your engine might leak with syn.

I would stick with a good grade of dino. Dino is mighty fine oil and we can't complain about it especially in an engine as old as yours.

Good Luck,

Jim Henderson

 

I echo mr. hendersons thoughts on this one. change the oil and filter every 3000 miles and keep up on general maintainence. hope for the best.

 

waste of money

if you have ever put mineral oil in your auto switching to synthetic won't do any good except give walmart more profit...save your cash and do like the others say....frequent oil changes...

i know this because I have been told by various NASCAR mechanics while running my car at the track and watching them use mineral oils in their own street cars

if you have had synthetic since day one, then different story

 

synthetic motor oil gives less friction..there by giving you more power (not mcuh) and less wear. But ya..i wouldn't run it in an old motor. And from a friend that worked in the vette plant for a couple years..the oil they leave with is not the same mobil one you can buy on the shelf. Supposedly they have break in compounds in them.

 

Synth oil will save you money. I'll show you in Canadian prices. Discounting oil filters because you have to change them with same regularity either way.

4 L oil @ $2.00 each (not premium oil) $8.00
1 copper washer $0.50
Time
20k km = 4 oil changes total $34

4L synth oil @ $7.00 $28.00
1 copper washer $0.50
Time
20k km -= 1 oil change total $28.5

You can go more than 20k km on a synthetic oil change but even if you change at 20k km you will save a little money and the hassle of 3 additional oil changes. Think about it, that is 3 less times you will have to pull out the oil collection pan and wrenches, get oil on your hands and driveway and dispose of the used oil (3 less oil filled holes in the yard or 3 less trips to the local used oil depot). I run synthetic because I am lazy.

 

How can you go 4 times longer on synthetic oil? True it may not break down as quick, but the bigger problem is external contaminants. Eventually your oil becomes saturated with fuel. What people don't realize is that even a brand new engine burns oil. you don't see this because the saturation rate is the same as the burn rate. Fuel vapors are introduced into the oil at the same rate as the oil is consumed on new engines. older engine burn the oil quicker. Take a sample of your old oil to your local John Deer dealership. For $10 they will send it in and get it analyzed and tell you how saturated it is. I think going 4 times longer on synthetic is foolish. Like everyone is saying. Frequent oil changes is the best thing for your baby, I mean truck.