Am I thinking right?

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Jun 6, 2003
Petersburg, West Virginia
Hello- I recently purchased a 1997 full size silverado 350 vortec with 127000 miles. The truck was in like new condition. All highway miles with regular oil changes using havoline synthitic blend oil. I changed the oil using a pure one filter and had very slow oil pressure pick up at starting. The valves would clang for a few seconds. I droped the oil again and changed to a napa silver filter with 10w-40 motorcraft oil. Then no problems- instant pick-up no clanging of the valve train. Previous oil was havoline 10w-30 chevron type, with the pure one filter. Question- Do you think I am using the right viscosity for this motor with this mileage? Also, what do you think of the motorcraft-conoco oil. Seems to be excellent stuff. Any thought would be appreciated.
I think the 40 wt. is fine for summer, fall, spring for your your area but I think you are far enough north that switching to either a 30 wt or perhaps Delvac 1 for winter would be god. Motorcraft oils have done on the few Used oil analysis that I have seen but I would recommend the Delo 400 (chevron) or the Delvac 1300 in a 40 wt. A used oil analysis (UOA) would be good. The rest of us would then be a little smarter. [Smile] [Welcome!]
Like a rock, I think your Silverado would benifit from using a CI-4/SL 15w-40 motor oil. These oils are primarily intended for heavy duty diesel engines but are also rated for gasoline engines and are very well suited to your application. This will help increase your oil pressure and also help to keep your oil consumption very low. For winter you may be better off getting a PCMO 10w-40. You could also use a synthetic CI-4/SL 5w-40 motor oil in winter or all year but of course that will cost more. The CI-4/SL rated motor oils have a very robust additive package and will likely last longer and give you better protection at the same time. You may also want to consider the Schaffers 15w-40. This oil has produced some very good used oil analysis numbers. The Schaffers 15w-40 is also a little thinner at very cold temperatures than most other 15w-40 motor oils and also may last longer than some other similar oils however it does cost more and you may have to order. I hope you are enjoying your new truck. [ June 08, 2003, 12:15 AM: Message edited by: Sin City ]
I forgot to say I also think that Motorcraft and Conoco motor oil are both very good products. The Motorcraft 10w-40 oil was a good choice but I do think a HD 15w-40 would be an even better choice in warm weather. [ June 08, 2003, 12:13 AM: Message edited by: Sin City ]
Their is nothing wrong with a 40wt oil. I do have resevations about 10W40 though. Most 10W40 oils are full of Viscosity improvers and most OEM's forbide their use. THe 15W40 conventional diesel oils and synthetic 5W40 are a better choice. I know nothing about motorcraft oil. THe engine can handle anything from a 5W30 to a 20W50 without any problems. THe only thing to consider is what the temps will be before you change your oil. You would not want 15W40 conventional oil in the truck when the temps drop to -20!!! You truck might also bennifit from either a does of Nuetra 131 or Auto-RX. It never hurts to keep the pickup screen clean!!!
Thanks to both Al and Sin City, you really have me thinking about trying Delvac 15w-40 for year round use since being synthetic and having good flow in the colder months here in West Virginia. I would tend to think the extra tbn will help offset the higher cost, but I am trying to get at least 200,000 miles out of my ride. Again thanks and best regards.
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