5W50 synthetic oil ok? - 2004 Saab 9-5 auto

This seems very risky to me. Apart from the unusual high warm oil grade, it is odd that the large multi-grade span is sold cheaper? You have to ask yourself what can be the reason for that? Go for the API and ACEA accreditation as specified by Saab. Oil change isn't costly per mile anyway. Tip to UK owners: Halfords often have 5W-40 fully synt on BOGOF before public holidays.

I would say "yes", Costco is fine. Personally, I prefer Mobil 1 over Castrol, but they are both high quality oil products. Costco isn't likely to do much more than top off some fluids as part of their oil & filter change, and may use a lower quality filter than the Saab dealer, so check the filter brand at Costco too. [I now refrain from digressing into a discussion on why I don't like Fram oil filters.]

Because of the reference to Costco, I assume that you are in North America, but you don't mention a specific location. 0W-40 is very light weight oil for the summer months. My opinion is that the 5W-50 has the edge if you live in a region with a warm summer.

The explanation of the price difference between Costco and the Saab dealer is simple. Costco is for members only and they keep their prices low by eliminating all the checking that the Saab dealer promises. The Saab dealer doesn't need to reduce prices, oil changes are just a sideline of their main repair business and a service for their regular customers that want their cars worked on by the same technicians. That is an advantage that might be worth the extra cost the dealer charges: They know where to look for faults and can get a better "feel" for your car's needs if they see it in their shop for all its service requirements.

Walt Kienzle

Good point about the oil filter; I will check to see what brand they use.

You're right about North America - I live in Toronto, Ontario - Canada.

Often in the 30C's July & August.

Well, I certainly intend to take my Saab back to the dealer for anything other than maybe tires and oil changes (actually their prices for winter tires matched Costco's). Mainly I was curious about the different oil specifications and you've answered that question. Thanks for your comments.

Couple notes: The dealer is expensive because they screw you over. It has little to do with the alleged extra "checks" which take all off 60 seconds and are only done to try to sell you more overpriced services and material. They just screw you out of way more money that the services are worth.

As an example, my local dealer charges more than $20 more for a synthetic oil change vs. a standard oil change. Let's examine that: It's the exact same labor. Mobil-1 costs $2 more per quart *retail* than dino oil. Saabs take 4 quarts. So, that comes to $8 and the dealer charges $20. Dare I mention, they buy their oil in drums and pay less per quart than you and me. Explanation? They screw you over.

That all said, filters do vary in quality. Wix is good and/or their OEM products. Likewise Mann (old Saab) filters are good. Others vary, check to see what they use.

Also, Costco is likely to employ monkeys who don't understand the copper washer on your pan or the fact that it is aluminum and requires less torque. Every story I see posted about a stuck or stripped oil plug begins with "I went to the el-cheapo oil change". Likewise, those places are famous for putting in the wrong product (e.g. tranny fluid instead of oil) and overfilling the crankcase (often destroying motors). Use them at your own risk.

Also, Castrol is a dino base (core) blended back to synthetic. Mobil-1 is fully synthetic. Since they cost the same, I use M1. I don't think I would be too concerned about using Castrol as long as you use reasonable intervals for the change.