Is it safe to use in older engines instead of on convential oil? If so would you recommend it? My instructors at school say it is but we dont work on older vechiles past 2000 so I never seen it happen in person I want to hear peoples answers on here.

Thanks

 

the synthetics will clean sludge from inside the motor.
so sometimes with an older motor that has a lot of miles on it, it can develop oil leaks. if its been well maintained, the odds of an oil leak drop.
other than possible oil leaks, it should be fine.

 

Im not trying to sound stupid but is 66,000 miles alot of miles on third gens or just the 2.5 it self

 

Wow a 2.5L they are getting kinda rare.

What shape is the engine in?

I have always wanted to drive one of the 2.5Ls

 

i using synthetic oil at 150000 miles with no leaks.

 

at 66k if its been decently maintained, even the 2.5 should be fine on synthetic.

i've driven thirdgens with the 2.5. the first one came in with the customer complaining of low power. after a very short test drive, i pulled it in the shop and opened the hood.
my first thought was someone stole half the motor, which is what i told the customer, LOL. they were not amused.
a check of the vin showed it did in fact come from the factory with a 2.5 4 cylinder motor.
the 2.8 V-6 was slow, but the 2.5 4 cylinder was beyond slow.
turned out the guy had bought it used without driving it, hearing it run, or even opening the hood.
he gave it to his daughter who was in collage and went and bought another one, but with a V-8 TPI.
later he claimed she was getting alomst 40 miles per gallon highway.

 

The bold part, ALL engine oils will "Clean sludge from inside the motor". ALL motor oils, Fully synthetic, Semi Synthetic, and Mineral oil...all of them have detergent in them specifically for that purpose. Only exception is specialty, "NON-DETERGENT" oil which you won't even find in most stores.

The part about synthetics leaking more than regular oil is left over "lore" from the old days (30 years ago). Todays synthetic motor oils leak no more and no less than any other blend of oil.

66k miles on a 2.5L is not a lot. In fact, I'd call that "low miles".

You can determine if it has "sludge" build up (due to lack of maintenance/oil changes) by simply peering into the oil fill with a flash light. Do you see chunks of carbon looking crap? If so, change the oil...a lot (maybe every gas tank full), and use cheap oil until it's clean in there.

 

Tom, your right, i probably should have said synthetics will clean better than standard oil will.
i believe its because synthetics don't break down as fast as regular oils do and not because of any additional cleaning agents.
of course that includes always using a good quality oil filter.

well maintained on regular oil, oil and filter change every 3000 miles or 3 months.
well maintained on synthetic, oil and filter every 10-15000 miles or once a year.
that is with the motor being allowed to get to full operating temp and kept at temp for at least 15 minutes almost every time its started.
if its ran hard, in dusty conditions, or a lot of short trip driving the mileage interval drops.
if the vehicle is driven long distances almost every time its started, the mileage between oil changes can be extended.

i've been into motors that used a good quality regular oil that were well maintained and they do have some sludge. the higher the mileage the more sludge/build up they have. you find it mostly around the main seals and bottom side of the valve covers.
motors that were well maintained that used synthetics with around the same mileage have always been cleaner.
if the seals are hard, if its excessive removing that build up from the crankshaft can cause oil leaks.
if the seals are in good condition, removing the build up won't cause an oil leak.

motors ran with synthetics also seem the be much less susceptible to sludge build up when ran with a cold or bad thermostat.
motors with too cold of an operating temp ran with regular oil will get unbelievably dirty pretty quick, even with regular oil changes.