Well i have a 94 formula with a rebuilt engine and about 27k miles on it. When i bought it they told me they were using none sinthetic 10-40 oil. The same day i changed the oil and been using mobil 1 10-30. Lately I've heard a mix of good and bad things about Mobil 1. What is the best oil i can put in my baby?

You want the best?? Like 8-9 bucks a quart? Redline, Amsoil, Royal Purple

Okay...how many miles on the new motor with non-synthetic oil?

most miles were not synthetic... like 24k

Okay.

Good thing. Best to run a motor on the cheaper oil for a while before switching to synthetics.
Mobil 1 is great oil. That is what I use.

I use mobil 5K in my car. 1 question Luos... when the guy changed the oil, he said i hafta run 10W-30 in the winter and 5W-30 in the summer. Do you do the same thing???

Nope.
I run 5w-30 year round in both cars.
Granted, the T/A never leaves the garage if the weather is cooler than 45-50 degrees.

I use mobil 5K in my car. 1 question Luos... when the guy changed the oil, he said i hafta run 10W-30 in the winter and 5W-30 in the summer. Do you do the same thing???

Wouldn't it be the other way around? Either way, I would run the Mobil 1 5w30 all year as well...

Lous you said you run 5-30... is that what u recommend for me pr should stick to 10-30 remember approaching 30k miles on a rebuilt...?

I use Castrol syntec 10W30 year round ,But I am in a warmer region .Per the owners manual . Rob

In the grand am I run castrol syntec 20-50 in the summer and 10-30 in the winter. The camaro gets 5-30 mobil 1 but is only out late april to mid october anyway.

thing about castrol syntec it is not a full syntec like mobil 1, and wouldent 10w30 in a new motor hurt the rings? Would it be to thick? I have a 305 with 120,000 should i run 10 or 5, 30?

If you have over 75,000 on a motor using conventional oils, don't change to synthetic. Some do without problems, others start burning oil.

I use Mobil 1 5w-30 year round. And we get extremes in temperature here. Just last weekend we set new record lows (below zero). This summer...well over 95 degrees for several days.

why would it start burning if i go with synthetic?

Rings are used to the conventional. They can't handle the much more slick synthetic. The rings can start to allow a little oil to blow by...thus burning oil.

OK im still a little confused... I live down in Miami Where temperature is year round at 80 with alot of humidity. Should i go 5-30 or 10-30 Mobil 1. Remember approaching 30k mile on rebuilt engine that has mostly used 10-40 non synthetic oil

OK im still a little confused... I live down in Miami Where temperature is year round at 80 with alot of humidity. Should i go 5-30 or 10-30 Mobil 1. Remember approaching 30k mile on rebuilt engine that has mostly used 10-40 non synthetic oil
I would think you should be fine on Mobil 1 5w-30 or 10w-30.

ok for me what is a good regular oil to run in it then? i like castrol. what you think?

Castrol is good.

I use the red lable german Castrol 0w30 synthetic
Check it out at www.bobistheoilguy.com (http://www.bobistheoilguy.com)
Plenty of testing - they even have their oil analyzed for wear metals
check Patman's posts.
I been using it for over a year - no problems.

how manny miles are on your engine?

I use the red lable german Castrol 0w30 synthetic
Check it out at www.bobistheoilguy.com (http://www.bobistheoilguy.com)
Plenty of testing - they even have their oil analyzed for wear metals
check Patman's posts.
I been using it for over a year - no problems.
Also great oil if you can find it.
Full synthetic though 97cavalier.

I normally use Mobil 1 but I have used syntec in the past as well. I have a Corvette LT1 though and those got Mobil 1 from the factory and thats all that was recommended.

I have to agree with synthetics. If you have a car with low miles, ok run it if you want. But in the higher mileage engines, it might just be a waste. Personally I have a 350 in my car with high miles. Well 83,000 on a 78 is good but still high. I run 10-40 natural in the summer and 10-30 in the winter, I live in the cold climate so I do lower the viscosity for the winter to help in the cold start oil flow. It's a common practice here to use lower vis in the winter and higher vis in the summer. You also might want to run a natural oil with a synthetic additive to help in lubrication. I've used Lucas before with good results.
I have only used synthetics in one car. I used the castrol syntec in one of my "old" new cars with decent results. From what i hear now, royal purple is the front runner in synthetics, and amsoil is also a good alternative.

Mr.luos, did you say run synthetic?

I have 59000 miles on the Bird. Been using synthetic after I broke it in. Started with Mobil one then went to Amsoil - about 9000 miles ago I went to GC 0w30.

Any synthetic is better than dino oil.

Mr.luos, did you say run synthetic?
Nothing but Mobil 1 5w-30.

Started the Grand Am on it at 32,000 miles.
Trans Am has been getting it since 10,000 miles. Right now I am running cheap conventional oil for break-in, but I will switch back over to Mobil 1 in about 3,000 miles.

Use 5w-30w AmsOil.. You can't go wrong.. A little expensive but lasts for 25K miles without changing, all you have to do between that 25K is change the oil filter 2 or 3 times, depending on how you beat on it... :)

Use 5w-30w AmsOil.. You can't go wrong.. A little expensive but lasts for 25K miles without changing, all you have to do between that 25K is change the oil filter 2 or 3 times, depending on how you beat on it... :)
I would NEVER let ANY oil go past 5,000 miles. Even if it is proven to last that long.

Although I do agree....Amsoil is good stuff.