For the first oil change on my '05 GT at 1500 miles, I went with the recommended Motorcraft Premium Synthetic Blend 5W-20. Then at 3000 I switched to 5W-20 Mobil 1. I have used Mobil 1 on both my 1987 GT and 1995 GT, and consider it cheap insurance.

Anyway, I change the oil every 3000 miles, and was able to find the 5W-20 Mobil 1 in Walmart for the changes at 3000, 6000, and 9000 miles, but now I have 12,000 miles and cannot find Mobil 1 5W-20 anywhere! I've been looking locally for the past two weeks, at two different Walmarts, and two different Autozone stores.

In fact tonight at Walmart, the only synthetic 5W-20 they had was Pennzoil. Last week when I went looking, Walmart had 0W-20 Mobil 1, but now that is gone.

Is it okay to use 5W-30? There is plenty of that available. I really don't want to go back to the Motorcraft 5W-20 synthetic blend after switching to Mobil 1. I'm also thinking about using the Pennzoil 5W-20 synthetic, but for some reason I don't trust it like I trust the [more expensive] Mobil 1.

Is 5W-20 Mobil 1 scarce everywhere?

 

If you don't use 5w20 you may screw up the variable timing!

 

Go with the 0W20, the 0 is the cold starting thickness of the oil, the 20 is the hot thickness. Your engine spends most of the time hot, and having a thinner oil when it is cold is not a bad thing at all. The oil will flow easier and quicker if it is thinner, as in a 0 weight. Using 5W30 won't screw up the variable valve timing, but it might make it run a little rougher and lose a little bit of MPG's.

 

I have found it at pep boys, autozone, advanced auto and walmart. I watch for sales and have oil and filter already on hand for the next two changes on both cars.

 

I have been running the 5W-30 Mobil 1 for the same reason, no 5W-20 on the shelves. The thinner oil is to reduce engine losses and get a little more gas milage. I am on my second oil change and no complaints. 3k mile interval is a bit conservative for a full synthetic. You might as well run full mineral or a para syn. I run my Mobil 1 12k miles, the extended service Mobil 1 filter and change the filter every 3k to 4k miles. The the Mobil filter is claimed to have enough surface area to handle 12k to 15k miles. Careful if considering the Extended service Mobil I. Great for older cars, but it has additive levels newer car smog systems don't like.

 

I really had to look for the 5W20 in Mobil 1 at Wal Mart... the only way the carried it was in a 6 qt half case. I was hoping to find the 5 qt jug, 'cause it's like $10 cheaper that way.... but yeah... I had to look at the back of the top shelf to get what I found... did you ask for it? or was it over looked? How thoroughly did you look (not to be condescending... I just can't assume that you really really looked)? Anyways... I'd stick with 5W20, as opposed to going to the 5W30... I've had Ford techs tell me that the heads don't get adequate oil on these motors with a heavier oil... simply because the tollerances are a lot tighter than the old pushrod motors. I know that there have been lots of people to suggest otherwise.... but I'd rather be safe than sorry. You should be able to get 5K out of synthetic oil... so it's not going to kill you to hold out. perhaps see if you can order it online any cheaper. Anyways... good luck.

 

clintoris - you might take a look at the shop manual engine clearance specs / tolerances. You will be surprised this V8 is not a tight as you might think.

 

on post(fort bragg).the k&n filter here was 8.75 so that's not that bad

 

Check at a ford dealership for the Motorcraft as they usually carry it. And its not outrageous on teh price from what I remember.