5W30 will have zero effect on emissions. It will lower your fuel mileage by about .1mpg or less though. Emmisions testing does not test fuel mileage, it tests amounts of certain compounds in the exhaust. A different engine oil will have no effect on the engine's combustion efficiency, and how the emmision control system is working. Well, unless you switch to some 75W140 gear oil...then you might fail emissions testing...if you can get the engine to run.

 

Well I have to scientific basis or anything analytical to add other than my first oil change was to 5-30 with the same mistake you made. I could tell no difference. The next oil change went back to 5-20 and still I have not been able to tell. Both changes were with Mobil1. The next one will be 5-20 or 5-30 once I see the results that theedge67 ?? is going to post.

 

I was using Amsoil oil with an Amsoil filter but the cost of Amsoil is not worth it IMHO.

So I decided to switch to Mobil 1.

Glad to know that Mobil 1 5W30 is OK.

I was about to email Brenspeed about the "mistake" but apparently those guys know what they're doing.

 

Sorry, I forgot to post this earlier. The first 2 samples were of the Amsoil TSO 0W30, and I think the engine was still in the break in period because I do so much highway driving, so you can sort of disregard those samples. The other samples though are much more meaningful in my opinion.

 

What's all that small print say? If I wanted to read all that stuff I would go back to college.

 

I would like to add one more point. I run 5W-50 in everything I own, which is an 1988 F350 with the 460, the 2006 V6 Mustang and a 2008 PT Cruiser. I ran a 1998 Explorer too on the 5W-50, and all with no problems. I also plan to run it in my new 2008 GT, once it arrives and I get a thousand miles on the odometer.
Maybe this is too much information, but there are five forces which consume your power in a car, and they are:
1.) Gravity (going up hills)
2.) Wind Resistance
3.) Rolling Resistance
4.) Pumping Horsepower (the power required to compress your charge, which is a function of the RPM and the displacement)
5.) Mechanical losses
The slightly thicker at operating temperature oils appear to your vehicle as a slight increase in Mechanical loss, because the slightly thicker oil requires a slight amount more power to pump it to the bearings. But, your bearings will hold a substantial greater amount of piston load. If you double the operating viscosity, the bearing will hold twice as much before crashing. Also, your bearings are better protected from lugging conditions, which are demanding for any bearings (slow rotational speeds reduce what a bearing can support on its hydrodynamic film).

 

Sorry, I should have included an explanation of what that stuff is. The numbers for the different metals and elements are the wear metals in parts per million in the oil. Lower numbers are better, obviously. Normal ranges differ depending on the engine make/version.

The important part of this chart are the top 5 metals listed in the chart. Those are the main wear metals. The rest like calcium and molybdenum are additves to the engine oil. The bottom part of the chart lists the physical properties of the oil, showing what condition it is in.

The TBN is also important, it is the Total Base Number. It shows the amount of active additive left in the oil to combat the acids produced during combustion in the cylinders. As fuel is burned, acidic compounds form and get into the oil. Left unchecked, these acids can eat away at metal and cause increased wear on parts. Oil has additives to combat these acids, and the TBN tests that. Anything below 1.5 and it is time to change the oil. Fresh oil starts out around 8-10.

In a nutshell, it shows 5W30 produced lower wear metals than 5W20 in my engine on two occasions. 5W30 Mobil1 was lower than 5W20 Mobil1, and 5W30 Pennzoil Platinum was lower than 5W20 Platinum. I'm sold on 5W30.

 

^

All excellent information. I guess being in New Jersey has me thinking that ANYTHING would cause a failure at the inspection station...

 

Your car will actually explode if you put 5w30 in it. Trust me my best friend's uncle's brother in law is a master tech for ford and he said so. I heard that someone ran 5w50 one time and that's why the dinosaurs are gone.