OLD Syntec 5W50 - use it?

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Aug 23, 2002
Pacific NW
Eureka! I've unearthed a 6qt case of Castrol Syntec 5W-50, from ~1989 (pre-synth wars, it was intended for my '82 race fbody). There are no visible date codes on the bottles or box. It's API SH/CD, CCMC, G-4, G-5, PD2, and JASO. ILSAC GF-1. GM 4718M. Should I: a) Use it. b) Get a virgin analysis first. c) Auction it on ebay. David
Well, it should have been the genuine PAO back then. I don't know of anything that says motor oil goes bad after X # of years, though ~13 yrs old is probably as old as I'd care to try. I'd probably use it, assuming nothing's settled out or anything like that. Pour a quart into a clean glass jar, & look for cooties! [Big Grin]
OneQuartLow, if the oil were mine I would use it but I would first do what Stuart Hughes suggested and pour it into a clear glass or jar to be sure that it looks OK. I do remember that Mobile at one time had the shelf life of their Mobile1 oil listed as 120 months. So oil may not last forever but I would believe it to still be OK. Also I would like to thank Bob for creating this web site. I enjoy reading the posts and informative articles written by the members.
The Shell Europe website says that oil has a shelf life of about 4 years. Even though this Syntec is PAO, I wouldn't use it, 5w50 has to be the dumbest viscosity created. WAY TOO MUCH VII is needed for that spread. Plus it's too thick for most cars anyways. [ September 05, 2002, 05:39 AM: Message edited by: Patman ]
I agree with Patman. I have seen this stuff go milky at about 4k in a good engine, due to the breakdown of the VII's.
Okay, so maybe Smithsonian or eBay. I'm dying to see what an analysis looks like though. I'll open one up for a visual and send off a sample. Meanwhile, my mower oil supply grows. [Smile] David
Patman Mobil Oz and a very large no of Aussies would disagree as here M1 is 5W50. Every cnr store has it even supermarkets. Mobil sell it by the shipload. M1 0W40 and 10W30 are basically unknown except to oil nuts like myself. I wouldn't use 5W50 now but then neither would I run 30W crap in my vehicles except when using Auto-Rx as Pennzoil 10W30 Purebase was the only straight dino I could find.
Why would you guys need 5w50 though? With the weather not getting too cold, a 15w50 or 20w50 would work much better. And in the northern areas in cooler weather, then 10w30 would work fine. But that 5w50 is just too large a spread, you'd never want to do extended intervals at all.
I guess if you lived on top of a 12,000 ft mountain and drove down to the 100+F desert you might want a 5w50. Even then a syn 10w40 might be a better choice. My vote for dumbest viscosity is 5w20.
I agree 5W20 is dumb. But then so is 0/5/10W30 if you want turbos/engines etc to last. Take any vehicle sold worldwide and everywhere but the US the viscosity will be 0/5/10/15W40 or 15W50. Magically as that vehicle crosses the International Date Line on it's way to the US reccomended viscosity drops in the owners manual. Amazing or what!
Sprintman is right, it's pretty sad that our politicians dictate our recommended viscosities, not the engineers that build the engines. Any engineer who can honestly claim that 5w20 oil is going to be better for that new car compared to something thicker is simply a liar. Although I still stand by my belief that a good well built 10w30 provides all the protection you need, even for hard driving.
posted August 03, 2002 05:37 PM -------------------------------------------------------------------------------- Hi,Here are the Blackstone numbers on Castrol Syntec 5W-50 with 5,600 miles.This was on a '99 Ford Econoline 150 with 4.2L Six at 24,300 miles.The driving conditions were seven weeks of mostly freeway and hot weather.One half quart of make-up oil was added.Universal Averages are in (#). Alum 2 (5) Chrom 0 (1) Iron 8 (40) Copper 6 (16) Lead 8 (9) Tin 0 (1) Moly 38 (37) Nickel 1 (1) Manganese 1 (1) Silver 0 (0) Titanium 0 (0) Potassium 0 (6) Boron 28 (37) Silicon 16 (28) Sodium 2 (50) Calcium 3023 (1575) Magnesium 6 (382) Phosphorus 717 (843) Zinc 904 (996) Barium 4 (2) Sus Viscosity@210F 88.5 (77-88) Flashpoint in F 445 (>385) Insolubles 0.3 (<0.6) Comments:Nothing too unusual showed up in this sample. All wear read at or below averages for this type of engine, which is a very good indication of normal wearing parts and careful operation. The lead did read slightly high compared to iron,though at this low of a level,we don't suspect it is coming from a problem. The universal averages show normal wear after about 3,700 miles on the oil. Feel free to run the next oil 8,000 miles. If wear and insolubles still read low,you should be able to go even longer. No fuel dilution or anti-freeze was found. Hi, Just thought ya'll might look here and ponder.How bad is it?
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