Why would you say that, read the reviews on synthetic oil, nothing but good stuff, When I first started over 5 yrs ago, the only reason I went with Pen full synthetic is because Porsch, put it in there cars, out of the factory, Hey man , if it's good for Porsch, it's good for my cars

 

Wow, old thread back from the dead.
I have been using the Amsoil ever since the original post. I change it every 20k. Good stuff.
It seems like there are more true or pure synthetics on the market now then there were when this thread started. Maybe the other synthetics are as good, maybe not. Amsoil has been around since the early 70s and has a great reputation, it is made in the USA and you can get it from independent dealers instead of chain stores. I like all those ideas.
I change my oil once a year, it runs cooler and quieter than it did with the factory blend. So barring any compelling information I will stick with the Amsoil.

 

I used to run the OEM recommended motorcraft in my car, but recently switched to royal purple. WOW what a difference. I get better mileage, noticeably better cold starting, warms up quicker, and actually stays minutely below the halfway point on the temp gauge, even in 100 degree weather. I will never use anything else in this engine.

 

There are two "Heavy Duty" & Synthetic, both can be used with any type oil.
Your using Pennzoil and I have used it back in the 70's & 80's. I have used Royal Purple and when I can catch it on sale I'll buy it, still 5 to 1 with Lucas stabilizer.

 

I know a lot of the Mustangs call for 5W-50 which, AMSOIL does have now. Just came out with it in the past month or so. You can check it out at www.TopPerformanceOils.com

You can also get a free AMSOIL catalog. Use referral code 1925242 and go to:

https://www.amsoil.com/AmsoilLogin/L...log&zo=1667299

 

Sorry, but I posted the wrong URL for the free AMSOIL catalog. It should be:

https://www.amsoil.com/AmsoilLogin/L...log&zo=1925242

 

I run regular oil and change every 5000 miles. Every car I have owned which has been many, go over 200000 miles with no problem. I think all this hoopla over synthetic is just that.

 

Just did my second oil change at 14,500, Mobil1 full synthetic 5w- 20 and man was it dark

 

Ive always used regular penzoil, its served me well

 

Yeah same here but I changed because the New Synthetic is supposed to be better