going from 5w-30 mobil to 15w-50 or delvac 1300

[steeltoe]

First off I would like to say what a wealth of information this site is! I've been digging changing my own oil since I was 14. It's good to know that there are others out there with my addiction. I have a 97 GMC Z71 with the 350 engine. I've always run syn. oil since I got it with 31000 miles on it. Now it has 80000 and I was thinking about going to a heavier oil ( 15w50 mobil 1 or 15w-40 delvac 1300). I've been going maybe 5500 to 6000 miles on each change. I was worried about the shearing of the mobil 1 but at the same time had thoughts about the non-syn delvac holding up. Any ideas from the "Lords of Lube" out there? o yeah, I use puroilator filters by the way.

 

[Al]

I'm sure that Delvac 1300 wold be a good choice in SC. You could also mix up a batch of 10W-30 and 15W-50 Mobil 1, or of course the best choice might be the Delvac 1 (5W-40)

 

[sbc350gearhead]

Why are you wanting to use a thicker oil? Is your truck using oil? IMHO a 50 weight is too thick for just a daily driver. 15w40 might be a good weight though. There have been a couple of very good UOA's posted on that engine. Check out the recent Valvoline synpower UOA posted on the 96, and check out my RP UOA on my 98.

 

[steeltoe]

no, I'm not using oil any, just thought maybe a thicker oil would help my pressure stay up a little more ( start up is ~60 psi, hot driving 40, idle at red light 25~psi). i also read that some people had an increase in mpg with the thicker oils and seeing that I drive about 50 miles a day round trip to work I was looking at that option.

 

[Eiron]

steeltoe, For 5k-6k mi intervals, I'd think D1300S should hold up perfectly well (& possibly be a better application for your climate). However, going from M1 5W-30 to M1 15W-50 or D1300S 15W-40, I wouldn't expect to see any mileage benefits. I think most of the reported increases have been with many of the full syn 40wts, & your two choices will be just a little too heavy to see much change. For that vehicle, in that climate, with those intervals, I'd change to D1300S for comparable protection at less cost.

 

[JohnBrowning]

First M1 15W50 is probably the best product that Mobil markets in a retail setting!! It is a thin 50wt. I have used it for years in daily drivers. SO far everyone that has tried it has had good results includeing a couple of Saturn owners. I think that you would be fine with 15W50. I do not know what your winters are like in NC so exercise common sense with viscosity apropreiate(sp) for temps. If money is not a factor and your vechile does not burn or leak a lot of oil I would stay synthetic. Delvac is a good oil but 1300 is not synthetic!

 

[steeltoe]

It only drops down to around ~20degrees F in the winter and that's only for maybe 2 or 3 nights. The only resources I have for oil are wally world, Advance, and Auto zone. So my opions are limited. The delvac is about $5.50/gal vs. $4.74 quart for the mobil. But at the same time I don't want to scrimp at the quality of the oil too much. Also, I've seen a lot of talk about German Castrol. How can you tell the difference between it and regular Castrol in the store? Thanks for all the input guys, it is greatly appreciated!!

 

[jsharp]

If you have those choices in suppliers, and really want to try a heavier oil, how about Rotella T 5W-40? It's $12.88 a gallon at Walmart. I still don't know why you'd want to go away from what's been working for you though. The German Castrol 0W-30 is easy to spot at Autozone. Look for bottles with the 0W-30 printed on a red background on the front instead of the normal yellow one, and look for Made in Germany on the back... [ November 29, 2003, 12:22 PM: Message edited by: jsharp ]

 

[steeltoe]

It was just a thought to go to the heavier oil. I was just getting opinions from some pros on this subject. If nobody thinks it makes a difference though, I'll stick to the 30wt. Thanks alot for the advice.