What Weight Oil?

[thiggy]

I have two older autos - '92 Escort and 94 Mazda B-4000, both with over 100,000 miles on the clock. I usually run 10 W 30, but a friend gave me a case of 10 W 50 oil. I live in central Alabama which has mild winters. Is there any significant reason that I shouldn't use the 10 W 50 in either of my vehicles?

 

[Pablo]

two words: owner's manual (if it's OK by the books you should be OK) I assume the oil to be synthetic because a 40 point spread just isn't so doable with a dino oil (Why didn't you post the brand?) I wouldn't know why you should need a 10W-50. All that said it may not harm the cars......

 

[Spector]

Well, back in the early 80s I ran Castrol GTX 10W50 exclusively in my VW Rabbit and that was in CT where winters were a little tough. Had 115,000 when I sold it but it seemed to do fine on that dino 10W50

 

[thiggy]

Hola Pablo. I didn't say I felt I needed to use the 10-w-50 (Castrol GTX non-syn). I was given a case and I just wanted to know if there was any reason not to use it. Could it creat damage to my engines? Warranty is not an issue here. Is this something I should hold off till summer and hot weather?

 

[Patman]

Tell us more about this 10w50, is it oil that has been sitting around for 10 years and may be well out of date? If it's not SL formula oil I wouldn't take a chance. Personally I think it'll be way too thick for those cars, not to mention the fact that it'll contain a ton of VII in it.

 

[Pablo]

thiggy (thigster? just kidding - like the name! ) I don't like that oil. I wouldn't use a dino 10W-50 in my lawnmower (hey I have a Honda)... The viscosity index improvers just aren't lubricants.... And as patman points out, if it's old, then for sure don't use it.

 

[Jay]

Another thing to consider is that the your gas mileage will suffer somewhat with the 10w-50. It may cost you more in gasoline than the oil is worth.

 

[satterfi]

I'd use it for short drain intervals like 3K miles.

 

[ZR2RANDO]

I probably would too.

 

[Last_Z]

quote:

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Originally posted by Greg Netzner: Not me, boy; I'd blend it with 20%-50% M1 0W-30 & run it at least 5k mi a pop! But then, I'm a cheap-a**-bas****!

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I think I would do that too. Rick [ November 13, 2002, 08:44 PM: Message edited by: Last_Z ]

 

[Eiron]

Not me, boy; I'd blend it with 20%-50% M1 0W-30 & run it at least 5k mi a pop! But then, I'm a cheap-a**-bas****! [ November 13, 2002, 06:21 PM: Message edited by: Greg Netzner ]

 

[Eiron]

OK thiggy, I feel my previous reply was a little too flippant. The other comments about this dino oil having a ton of VIIs is right on, but that doesn't necessarily mean it should be tossed. Rethinking the "blend it" concept a little, I guess what I'd REALLY do in your situation is blend it somewhere between 40-60% with M1 10W-30 or 15W-50. I think we've all agreed that the new 10W-30 & 15W-50 are M1's least VII, most stable (non-thickening/non-thinning) oils. Let's assume that you can expect the GTX to thicken a bit & thin a lot. The advantage to the 10W-30 is that it starts at a syn's 10W (better flow than a dino's 5W) & won't ever drop below a 30 when hot. The advantage to the 15W-50 is that it flows better than a dino's 10W & has a boosted anti-wear pkg in it to offset whatever degradation has occured in the GTX. Disadvantages? Well, the 10W-30 doesn't have the advertised add'l A/W pkg, & using 15W-50 means it's gonna stay a lot heavier. I really don't think 50wt is a problem for your vehicles/area, but it's obviously not a necessity. (Remember, it's still a 10W when the engine's cold.) I think I'd go with 10W-30 for 5k mi. It really comes down to your comfort level. I don't think using the GTX will harm either vehicle, & blending it is really just "insurance" if you don't want to toss it. I'm very much pro-extended-drains, so if I got a case free I'd try to make it work for me as much as possible. Also, I wouldn't run it in my newer, still-in-warranty car, but I would in my older, 160k mi car. But are YOU comfortable with that? I guess I should now add "anal" to my previous self-description.

 

[Dr. T]

To answer your questions....first off the 10-50 will be roughtly the same as the 10-30 (you've been using) with respect to start-up since, aft all, it is a 10...so you shouldn't have problems using it "in the winter". The difference in the 2 comes from the 50 which means the oil will be thicker at operating temperature. Will this matter? Probably not. You will have a thicker film thickness when hot. Shouldn't matter...the engine will run smoother, probably accelerate more gradually, economy may diminish ~1-2 mpg...but, definately safe to use...go for it.