View Full Version : Weight of Oil for the Cobra

09-05-2009, 12:48 AM
Ford recommends 5w-20 which I have been using--Mobil I. Why not 5w-30 instead for the higher temps. Also, I see that the 08 Shelby supercharged recommends 5w-50. Would this be a better oil viscosity since Ford now recommends it in their high hp model?

09-05-2009, 09:20 AM
The 5X50 is a full synthetic oil and runs around $7.50 a quart. I always go by manufacturers specifications so I would not change the weight. The modular engines have very close tolerances, I'd stick with the 5W20 if that is what is recommended.

09-06-2009, 09:56 AM
The 5w20 oil helps deliver greater horsepower & fuel economy (less resistance) according to the manufacturers with good protection while driving on the streets. Most people who take their cars to the track go to a heavier weight oil for better protection. If only street driving, I would stick with the 5w20.

09-06-2009, 11:15 AM
have always used the 5w-20 motorcraft synthetic blend here with no problems so far.

09-12-2009, 08:36 PM
The one and only reson Ford recomends 5W-20 is for fuel economy and nothing else.

You will have no problems going to 5W-30 or a 10W-30 in the summer months
I recomend Mobil 1 exclusively no matter what wieght oil you use.


09-12-2009, 08:44 PM
The one and only reson Ford recomends 5W-20 is for fuel economy and nothing else.

so there is no truth to it being because of the tight clearances in the motors also?

09-13-2009, 09:45 AM
I have been running 5w30 for at least 4 years now and have never had any problems. I am going to go even thicker as I run mine at the track. I used to run Mobile One but have changed to Royal Purple on the advise of multiple mechanics. For street driving & normal use they said Mobile One was fine. They both preferred Castrol for on the street and Royal Purple since I run mine so hard. Chevrolet recommends 5w30 Mobile one for their Corvette engines, but most of the guys running those have even gone to a thicker 40w or 50w oil. Any way that you go, I think if you do regular oil changes with a synthetic oil, your engine will do well.

09-27-2009, 11:14 PM
I run German Castrol which is an 0W-30.

10-13-2009, 03:02 PM
Everyone has an opinion on the best oil....and that's what 99% of them are.... "opinions", based mostly on unscientific hear say. Synthetic oil does seem to have valid scientific data to support it, but I seriously doubt there is much real difference in various brands. Royal Purple has a cult following, but so far I havene't heard anything other than anecdotal evidence to support it's superiority. Has anyone seen any independant studies??? Mobil One, Castrol, Valvoline, Penzoil, and others make high quality synthetic oils. Far more important than the brand is to change your oil (and filter) regularly. As to the weight. I would follow Ford's recommendation. They only spent several million $ on engineering the engine. Do you know more than they do? Take their advice!

Just another opinion..................