oil for chevy trucks

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Staff member
Dec 14, 2002
New Jersey
Hi, I have an s-10 4x4 (1998) with the 4.3L high output v6. The truck has 34k miles, and sees relatively limited service: always unloaded, always cold starts after sitting for a number of days. The truck is specced to use 5w-30 year round. After reading n here, I was pretty much convinced to use an xw-40 oil (x is not 10), so that I could get a little better protection. My first thought was to use rotella synth, even though it was a grp3, becasue it has a strong diesel type additive package, and was cheap at wal-mart ($12/gal). Now that price is up, and I have noticed that the oil gives me ticking for the first minute of operation. I think this is because the rotella is a bit thick on the 5w scale (never had this with dino 5w-30 pennzoil though). Since the truck sits a lot, I would feel more comfortable using a synthetic oil (mobil 1) with filter changes every 4 or 6 months, oil changes evey year or 5000 mi (the main consideration). I am deciding between M1 0w-30, 5w-30, 10w-30 and 0w-40. Right now, my choice is 0w-40. I think this because it has good long life specs, so it should last better whne sitting in the crankcase, in betwen runs. I don't think even 10w-30 will keep that much better of an oil layer on parts over the course of many days to a week, so the superior additives are the better criteria. the only concern I have is that this is an old design chevy pushrod engine, not a close tolerance honda, or a german engine deigned for better protection during the high heat stressful operation on the autobahn. The truck mostly is driven on the highway, but it loafs at 2000 rpm at 70 mph. I am slightly worried about wear and hydrodynamic wedges in between the bearings when the oil is thin at startup, as compared to even a 5w grade. Thatis really my only issue... I'm not a big fan of mixing in some higher viscosity 10w-30 or anything like that, I would prefer to use all one oil. Delvac 1 is the other viableoption, but at more $ than the 0w-40, and only available in gallon jugs (meaning that Id have a partial gallon open for the next year instead of a partial quart), the m1 scores points there (the engine is tight consumption-wise). So, In the end, what are your thoughts about cold operation protection, especially in the summer with this oil, and what should I do? Sorry for the lengthy post, thanks for your help, JMH [ March 12, 2003, 05:22 PM: Message edited by: JHZR2 ]
For your vehicle and the type of driving you do I believe you would be best off using the 5W30 dino oil year-round. This is because it has served you well, GM recommends it, it protects as well as synthetic for your application with regular oil changes, and it's inexpensive. Only when your truck gets much older would you need to consider using a xW40 oil; you'll find that the ligher oil cools better, promotes less wear, and provides better fuel economy. Or, I could be wrong.
I would go with the 10W-30. I think its a little more viscosity stable than the 5W. I personally would not go with the 0W-40 because of the huge multi-vis. spread. (But thats just me). Delvac 1 is super stuff. I know you don't like this option but I see no problem mixing up a batch of 3 quarts 10W-30 and a quart or so of 15W-50 (Mobil 1) I have done it.
I have a 99 S10 ZR2 with about 60k miles, I use 10w-30 and swap out 1 qt for 20w-50. I use Chevron/Havoline oil----just cleaned out my local Target by the way he he Rando
I was talking with Mobil the other day and mixing is fine and in fact can really be useful. I ordered Delvac 1 today for $21 a gallon. All of Mobil's synthetics are compatible but the only thing they warned me about is that you don't know exactly what wt. you will get when mixing which is why they dont recommend it. Other then that, its perfectly safe and effective. [Smile]
I ordered from a Lubrication place in Lakewood NJ. I'm hoping he didn't mistaken it for Delvac 1300. I specified 1 though.....
You can get delvac 1 for $21.66 from any Caterpillar parts distributor. Ask for their full-synth 5w-40. they may not know what youre talking about at first, but theyll find it... As for the not using 0w-40 because of VIIs, 5w-40 isnt that much different... why advocate 5w-40 and not 0w-40... the 5 units in 35-40 isnt much. ugh... what to do... JMH
<b>"JHZR2"</b> - I also have a 98 S-10 and similar type driving as you. Think I going to give Schaeffers 10w-30 7000 a try in it. Currently using Mobil 1 5w-30 but have seen some good reports on Schaeffers here so want to compare.
Just stick with what GM calls for. 5w-30 winter/10w-30 summer will give you years of trouble free service. My Dad has a 98 4.3L Blazer with about 115,000 miles, all with 5w-30 pennzoil every 3,000 miles and it runs A-OK. You'll probably get as good or even better wear numbers by sticking with what the manual calls for.
That is what I paid, $21.66. Received it today. Tough to beat this deal. Great oil to run is summer months. Dragboat and Tooslick have been saying this for awhile now. [Smile]
Good old Chevy 4.3 motors dont need any fancy synthetic oils to be maintained properly, especially if you don't haul/tow often. A good quality "dino" oil, 5w-30 winter and 10w-30 summer, will perform quite well. Make sure you don't go too thick, like a 15w-40, or you may starve the valvetrain of oil at each startup. Just my two cents.
There is quite a bit of difference between D1 5w40 and M1 0w40. Just look at the HTHS number for example. BTW, I had pretty good results with M1 10w30 in this motor. My analysis is posted. [ March 13, 2003, 12:45 PM: Message edited by: Jason Troxell ]
JMH, People tend to overthink these things ...at 5000 miles per year the engine will still be running fine when the rest of the vehicle is a pile of rust. I'd run the Mobil 1, 5w-30 unless you are having oil consumption issues. The 0w-40 would work fine as well, but I don't see any significant advantage in using that grade in a new engine, unless you were doing heavy towing and running very high oil temps. TooSlick
That's a good point, at 5k per year, even in 20 years the engine will only have 100k on it. Any engine can get that far with even half decent maintenance.
my main concern is additive chemistry... Sitting for many days to a week worries me a bit. However, changing oil every 3 months to be sure costs more than if I paid the premium fr M1 and just left it in. The 0w-40 is tempting mbecause it has very good specs and so the additive package must be quite robust. To be honest, I feel that the engine feels a bit sluggish with xw-40 in it (my MB diesel and BMW feel fine with xw-40 or 50 oils in them). So I want to minimize viscous friction, but protection and cost savings are major factors, as is good protection after sitting for long times. I think Ill use pennzoil / chevron 5w-30 for a while... I got some chevron for 68c, and pennzoil has really good flow characteristics. Then, maybe Ill move to a synth a little while down the road... Thanks JMH
I agree with the other posts...you're sweatin' things too much...M-1 5-30 should be more than adequate changed yearly for your application.
Castrol GTX 10w30 or Penzoil 10w30, and go 4k intervals. Those 2 are about the best dino oils around plus they have a little moly. When you get to 75k miles switch to a 40 weight oil from one of those 2. I don't think you'll need to spend the $ on synthetic for easy highway driving. Either way though you have a 4.3 Chevy, it's gonna last a LONG time with basic maintenance. Jason
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