Hello All!

I was considering switching my Bonneville over to Mobil1 5w-30 Full Synthetic. I've been using Havoline 5w-30. Any suggestions or comments on switching? Mobil says i should do shorter mileage changes for the first couple of changes because it may knock loose build up that could be hard on it.

-I change it currently every 3000 miles, religiously.


p.*. Car now has 101k on it. Ignore the sig mileage i have to change it.

Not to steal your thread, but my 2000 ssei states 10w30, not 5w-30. Is your Bonny requirement 5w?

book says 10w, motor says 5w. Its got 5w in there now. I live up north and it drops below 0 on a normal basis.

I run Mobile1 in my engine. Holds up great. Switch over, then change the oil after 3k to 4k. Then change filter and oil again and you should be fine. Just remember to watch it and change if needed.

Before you switch over, if you've ever thought of Seafoaming the motor, now would be the time. That should knock lots of crap loose!

I use Castrol Edge, because I think with my dipstick jimmy!!

no but seriously I used to be a die hard fan of Mobil1 until I had nothing but issues on Oil pressure in my Twin Turbo Stealth, I've used Edge ever since, oil pressure is perfect. I think they claim 8x more protection over Mobil1 so that'* a plus.

Used Mobil 1 in my Corvette and was leaking oil went back to regular 10w30 and the oil leak stopped.
From what I could find the engine seals were the problem but there are lot of articles on this on other websites.
I have been using regular oil in al my cars either 5W20 (Ford) or 10w30 as the case might be and have never had any problems and is a lot cheaper also, never found any advantage by using Mobil 1 but maybe in racing or turbo engines

I had 80,000 miles on my 2001 SLE when I switched to Mobil 1 5w30 Extended Performance 15,000 mile oil. That was 5 years ago. I now have 222,000 miles and have not had any problems with my engine and no oil leaks. The guys at Mobil 1 told me that 5w30 would be fine for my engine even though the owners manual called for 10w30. I see now that they have 10w30 Extended Performance 15,000 mile oil available. It was not available 5 years ago. I have been changing my oil every 15,000 miles. There are some gearheads that shudder when I tell them about my 15,000 mile oil changes. I just smile. I think 222,000 miles is proof that it is working for me. I didn't do anything special when I first used the oil. Went 15,000 right from the getgo. As I see it the 15,000 mile oil is about 50 cents more per quart then the regular Mobil 1 and lasts 3 times longer. Definetly worth the 50 cents more. Thinking synthetic is the only way to go. Should be way better protection, less oil changes, less waste oil to store or to have to drag to a recycle center and in the end probably as cheap as regular oil since you don't have to change it as often.

I switched my other two vehicles (the Bonneville and my 99 Silverado) over to Mobil 1 since that is what my Corvette runs, I just couldn't see having three different oils around and have standardized on Mobil 1. I have experienced no ill affects at all.