synthetics or regular oils??

[EASY]

My PT has about 75,000 miles on it.Im thinking of using one of the newer brands of oil that claims to be able to extend motor life by reducing sludge and carbon build up.I've always heard its a bad idea to change oil brands on a car after a certain amount of miles.Since I got this car used and have no idea of what was used before Im stuck anyways.Would it hurt to start using synthetic oil?I'd like to use what ever is going to do the best job.
Does anyone know if its alright?Im also concerned that if I use one that has a detergent additive that I'll start to have all sorts of problems.Any ideas?

[Hooligan]

Im also concerned that if I use one that has a detergent additive that I'll start to have all sorts of problems.Any ideas?

Any oil that is used in cars now a days, are detergent based. Makes no difference who makes it.

As far as you other question, I as well as you, must assume that just 5w-30 or 10w-30 has been used.

[CREWZIN]

Hooligan is correct on both his points. As far as switching to Synthetic now, it won't hurt a bit. If your ever short of oil and have been using Synthetic, adding a can of Dino oil won't do any harm either, but try and stick with one or the other. You might even find a slight increase in gas mileage because of the properties in Synthetic and you can extend the time between oil changes too.

[EASY]

Yeah I hear you,but with the high cost of oil these days I was curiuos if these other brands were worth the extra dollars.I can always find something else to spend on for the car.But if they do extend engine life then its worth it to me.You've all seen the ads claiming to do so much for your motor.Its kinda like that saying ( if you cant dazlle them with the truth baffle them with bullshit ) .So I just wondered what or which is the best to use.

[CREWZIN]

Sitting here thinking of a good answer for you, but there's too many variables and too many questions. Do you do a lot of stop and go driving? Do you almost always drive 10 miles after you start up the car to get the oil heated up to operating temperature? Do you switch to a heavier weight oil in summer, lighter weight in winter? Is the car garaged in winter? Do you change dino oil every 3,000 and replace the filter?

If longer engine life is the top question, here's my answer: Dino oil and filter changed every 3K, Synthetic oil and filter changed every 5K; you'll probably never have oil related problems in the lifetime of your ownership with either. Not saying you'll never throw a rod at 200,000 miles, but it wont' be because of oil failure.

[quicksilverdon]

I don't think there's any question that sythetic oil is better. It takes temperature extremes better than conventional oil. Synthetic oil isn't hype, it really is better.

[bados]

I started using Mobil1 on my '05 PT at my first oil change. Most of my driving is high speed turnpike/highway with little city. I have 65,000 mile currently and change my oil every 6000 miles. If you go to synthetic, have your engine flushed first before adding your new synthetic. There are some places like Jiffy Lube or Mobil 1 Car Care that offer this service.

[mowerman]

All good points! Since you do not know the car use a semi-syn. for 2 or 3 oil changes at 3000 miles. This acts as a flush and keep and eye out for leaks. If no leaks go to a full syn. any name brand is good. This is what myself and a ton of other people do when using a full syn. At the 5000 mile mark change the filter only and top off the oil and then do and oil change at the 10,000 miles. You ask yourself how is this alright? It is because syn. oil does not break down like dino it mainly gets dirty with very little break down. You can find out more about this at web sites like Amsoil. If your PT starts to leak after going to syn. switch back to dino and the leaks will slowly stop as the old dino does its thing.

[quicksilverdon]

Yeah, the leaks occur because of the detergents in synthetic that eat up the sludge that is plugging the leaks!

[mowerman]

That is a fact sorry that I did not put that in reply.