2003 Chevy S-10 Oil Recommendation - High-Mileage 4-Banger

Tiny
OLDECROWE595
  • MEMBER
  • 2003 CHEVROLET S-10
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 95,000 MILES
Bought this truck about 2500 miles ago. Engine seems pretty solid, considering that this was a fleet vehicle for a number of years. I have a couple of concerns regarding the engine oil, though.

At cold start-up, there is a brief knocking that appears to be coming from the bottom end. It's very brief, and disappears after a couple revs. When cold, oil pressure reads a little over 60 on the panel gauge, and drops down to 20 when fully warmed up @900 RPM. I'm thinking rod bearings might be a little on the worn side, although probably not a big issue at this time.

I'd like to insure that I get maximum oil protection at startup, as well as hedge my bets during the hot summer months with the A/C running constantly (those days are right around the corner). The majority of time will be spent on city roads and interstates.

I'm thinking about going with Mobil-1 high mileage 10W-30. I've heard good reports about synthetic oil in older engines, and currently have no oil leaks to speak of. What's your take - you reckon the benefit is worth the extra $$$?

GM recommends 5W-30 for this engine, which is what I've been running all winter. I figure the 10W-30 might help with the cold starts, all else being equal. Since this engine has probably been run pretty hard for most of it's life, do you think it's prudent to consider a 10W-40 for high-temp protection as well?

One thing I've learned over the years is that good oil and frequent changes will keep a lot of boogymen away. Appreciate any information about this particular engine.
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Saturday, April 24th, 2010 AT 12:41 PM

3 Replies

Tiny
JACK42
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The 5-30 will give you faster oiling on cold starts than the thicker 10-30 or 10-40. Use the proper filter as well, I believe that the A/C Delco filter has a check valve in it to prevent total drainback for cold start oiling since the filter is laying on its side. The pressure numbers sound good, I wouldnt worry about that. As far as synthetic goes, I run it in all of my vehicles, but I have seen some start using oil when synthetic is used at higher mileages, so it may be something to keep an eye on if you go that route, otherwise I would use it, a tthe suggested weight of the manufacturer
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Sunday, April 25th, 2010 AT 7:36 PM
Tiny
OLDECROWE595
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Thanks Jack, your advice makes sense. I've used full synth oil in a number of newer vehicles with excellent results, but this is the first time I've considered it in an older/high-mileage chariot. I plan to keep this truck for at least a couple of years, so extending engine life is a biggie.

I'll go ahead and load 'er up with Mobil-1 5W-30 and see how it goes. I'll be sure to post back with my results. Thanks also for the tip on oil filters - that could be a really important factor. Times are not easy right now, and we all need to get a little smarter about vehicle maintenance.

Thanks again.
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Sunday, April 25th, 2010 AT 9:15 PM
Tiny
JACK42
  • MEMBER
My pleasure.
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Sunday, April 25th, 2010 AT 11:22 PM

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