first I know there is probobly lots of these threads and if any one has a link to them can you please give it to me, all the ones I found when I searched just brought up new vehicles discussions ie 2005

1985 f150 I6 4.9l 4spd manual 167000km 2wd

well after many oil changes over 1000km (5) the oil is finally staying clear for extended time, I will be doing a few more oil changes and am wondering about switching over to synthetic oil becouse it is supposed to protect better and get better gas mileage. I have been using 5w30 in the winter and 10w30 now in the summer, just whatever brand is on sale at walmart or my local auto stores.

I have replaced the valve cover gasket and the oil pan gasket becouse they were leaking, I dont see any other leeks, and I dont appear to be loosing oil, I am not loosing coolant either so I think the other seals are all good. no oil in the exhaust.

I have heard that the synthetic oil will leak and also swell the cork seals causing them to fail if I ever go back to regular. apparently I will also burn the synthetic oil? no Idea how this is possible if the whole point of synthetic is having all the same size molecules and no impurities in the oil, if that size of molecule would burn easily then it would not be used in engines in the beginning, burning oil means the creation of sludge.

has any one ever done this on this old a vehicle? and what were your results.
thanks in advance
Matt

 

Synthetics are awesome for the right application ...

The typical everyday driver / commuter can benefit from synthetic.

Synthetics absorb heat better than dino, but do not dissipate it as well, so ultimately you'll see higher oil temps, no big deal, synthetics can handle the heat better than dino.

You burn more synthetic because more sticks to the cylinder walls, synthetics have better penetrating qualities and adhere to the metal much better.

Once going to synthetic do not go back to dino, I don't believe this is an issue with todays oils but it was in the past.

I use synthetics in most gear boxes, dino in most motors, flat tappet cams prefer dino, however I do run Klotz Synthetic 2 stroke in my Polaris, Klotz Synthetic 20w50 in some race motors.

-Enjoy
fh : )_~

 

Every vehicle, truck or car, that I have put synthetic oil in has run better and gotten better MPG's. And because you can go longer between changes the cost works out the same or less. Add a free flowing air filter like K&N and you will see a difference. Most of the silly stuff you hear is from those who don't use synthetics.

Here is an excellent example, my Son and his 2000 Mustang, V6 auto. I just repaired the rearend and filled it with Royal Purple gear lube. It now turns smooth as silk and makes no noise. I also use synthetic oil, K&N filer, Flowmaster dual exhaust, E3 spark plugs. He's 19yo and drives like a typical teenager, heavy on the right foot. Yet with all his spirited driving he still gets over 25mpg. The car bearly got 20mpg when I bought it. On a recent 4 hour trip to NC he told me he hit 32mpg. Not bad for a little car that will lay down a couple of nice black marks on the street.

Sythetics work you just have to take a leap of faith.

 

I personally would not waste money on synthetic in a older vehicle. It's claim to fame is longer intervals between oil changes, and thus it justifies the extra cost. It is a better oil, and lubricates better than regular oil, but I think people are missing the point of a oil change. You change the oil just for the reason you did; to get rid of impurities in the oil. The oil has detergents that contain and carry the water, gasoline, soot, etc, that gets in the oil during normal operation. The whole reason to change the oil is not because it's wore out, but because it's full of junk and needs to be drained to get those contaminates out of the engine.

If you want to run synthetic, by all means do. But I would not extend the oil changes longer than normal.

 

Personally, I run synthetic lube in trans and diffs, but just a good, high quality dino in engines.
I tried the synthetic oil in my nissan engine, and found little gain for the added cost, so I went back to dino. Other than 15-20K on the syn, it has clocked nearly 1/4 million miles on dino.

When I say high quality dino, the stuff I use is approved for use in aircraft engines. I can't run down to walmart for it, but it doesn't cost much more than what they sell.

 

I use synthetic in all my trans., diff's., p/s, lube and dot4 brake fluid. The oil that I use varies, but it is always a good, quality oil and filter. And I use a motor flush at every oil change.

 

I agree synthetic would be a good choice in the tranny/transfer case/differential, or other gearbox. They would benefit from the properties of the synthetic oil, and they do not normally get all the contaminants in them like a engine oil does.

 

thanks every one, the main reason I was thinking about switching is for the supposed increase in mpg
has any one experienced an increase?

what properties of the synthetic help in the differential and gear box?

also I put a full can of sea foam threw the engine (half in the carburetor and half in the brake vacume line) in 2 intervals break vacume first then turn off let sit for 15 minuts then drive 30 km repeat with the carburetor.

there was very little smoke only for about 30 seconds when I stated it up and ran at 2000 rpm after that I drove the 30km

the second time it only smoked for 10 seconds (I timed it)

so I think the seals are being held together by the seal not by sludge so I dont think I would leek if I switched )only reason I will switch is becouse I do short sprint drives in winter at -20C to -40c and if there is an increase in mpg. I will still change my oil every 6 months/5000 kms even when using synthetic (or whenever it gets dirty whichever comes first)

 

I change my oil every 3-4 months or 3000-5000 miles, sooner if it gets dirtier. And I use a can of motor flush at every oil change. I really don't think it matters whether you use synthetic or dino in an older or high mileage engine, as long as you use a good quality oil and change it regularly or when it gets dirty. My wife's 2005 Mazda6 calls for 5w20 synthetic oil, my riding lawn tractor calls for synthetic oil, while the rest of our vehicles don't.
On a side note, I have been thinking of trying Rotella oil in my gas truck. I have read several places that it is a better oil. Although I have more research to do on that idea.
Good luck and keep us informed on any changes in your gas mileage due the change in oil.

 

I wouldn't go expecting noticeable increases, however it all adds up if you're a commuter and drive lots of miles.

As I already stated Synthetics have better adhesion and penetrating properties.

They are also better under shock loads then dino, Typical Synthetic oil is not an 'EP' oil yet it has EP type properties. (EP = Extreme Pressure)

You can get Synthetic EP or Dino EP.
Synthetic EP's make awesome assembly lube, just don't put it on new cylinder walls, rings won't seat.

NEVER use an 'EP' rated oil in anything that has yellow metal. (Copper, Brass, Bronze, etc...)

EP oils are very easy to identify by smell ... The typical Hypoid gear oil smell! Synthetic or Dino ...

-Enjoy
fh : )_~

 

My vehicles had noticable increases in HP and mpg, BUT, I did more than just switch oils. I made other mods that all worked together with the synthetic oil. I helped the engine to breath better too. Just switching to synthetic oil, I don't know how much of a gain you would get. I've never tested that 1 change alone. Maybe I will when I get my 300 back from the machine shop. I always break in my engines with dino oil before I switch.

There are sooooo many factors that effect mpg's.