Chevron Delo 15w40 in '99 GM 5.7L V-8? Or is it too "thick" ?

Messages
105
Location
College Station, Texas
I've been browsing this board since Nov. '02 and I'd like opinions from any of you esteemed and enlightened individuals who care to impart one. I want to go with Chevron Delo 400 on my next change for my 1999 Suburban with 74,000 miles, for several reasons which include the outstanding UOA on the BMW with 6,200 miles on the oil. I'm planning on running it at 4,500 mile drain intervals, with a UOA at perhaps 3,000 or 4,000. The 15w40 is readily available at WalMart at a good price, and with the hot Texas summer coming on I like the idea of a 40wt. However, my owners manual calls for 5w30, or 10w30 as an option in temps above 32F. The manual specifically states "do not use 20w50". No further mention about other grades. I've read other posts here, and in one TooSlick (whose opinion I value greatly) states "I have been recommending it to owners of older Mercedes diesels as well as slow revving GM V-8 engines." I'll be changing soon...should I go with the 15w40 or order the Delo 10w30 from the local distributor? Any opinions would be appreciated [Smile]
 
Messages
33,973
Location
Southern NJ
I think it's a good choice. Most cars these days call for 5w/10w-30 wt oils. When the car or truck ages, a 40wt is a good choice. There are some cases where a very tightly built Jap engine will maybe show higher wear numbers with a 40wt due to excessive heat. But in your engine it's fine. Molekule is trying to gather data for viscosity requirments based on clearances. This is a common topic. The Steve Bergin article leads you to think viscosity has nothing to do with wear, and in fact 20wts are now becoming more popular. Also, if you check out the Mobil web page in New Zealand, you will find that practically every car in the US, runs on a 40wt or even 50wt oil over there. I think a 50wt might kill your MPG and that is probably the only reason they are telling you not to use it.
 
Messages
9,448
Location
USA
You can use it no problem! 5W30 dino oil in Texas heat is insane.I think that the 15W40 will workout much better for you!
 
Messages
3,317
Location
Bolivia
Delo has excellent flow characteristics with a -39 flow point. I usually increase a grade or so when an engine starts consuming oil. But I stick to the manual when new.
 

Al

Messages
19,157
Location
Elizabethtown, Pa
I think it is a good choice. I switched to Delvac 1 on my son's GrandAm at 25K miles. I just changed yesterday with 8K miles and put in another shot. I can't wait to get back the analysis as it will be comparing against M1 10W-30 both triSyn and SS. Unfortunately with Shaeffer's it takes two weeks to get results [Mad] . As was mentioned-Texas is the perfect place for 40 wt.
 
Messages
3
Location
Los Angeles
The best UOA I ever got out of my 99 GMC 6.0 was with 15-40 delo 400. I switched to Mobil 1 delvac because I use a bypass filter on this truck, and I thought the delvac would filter better through the bypass. The lead levels (still low) are slightly higher with the delvac. I may switch back to delo 400, change more often, and save money in the process. Delvac 1 still seems like a good choice for other vehicles I have, though.------Alex
 
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