Schaeffer's 7000 5/10w30 + 15w40 for piston slap??

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Jul 17, 2002
Oil gurus: I have a 1998 Chevy Monte Carlo with the 3.1L V6 and a mild case of piston slap. The intake gasket leak has slipped me so far but the car only has 55,000 miles so I will knock on wood. I have been running the Schaeffer's 7000 5w30 in the car for I'd say around 18 months and am well pleased. Could I possibly add a quart or so of the 7000 15w40 to minimize the piston slap or would the thicker oil be a bad thing to do?? I can also go to the 10w30 blend if you guys think it may help. Thanks for any replies.
Before you point your finger at oil, run a can of GM Top Engine Cleaner thru the throttle body, or a main vacuum line. Follow the instructions onn the can. This helped a lot of noisy 3100s at my dealership.
#700 15W-40 is a diesel engine oil so it has a very different additive package from #701 5W-30 or #703 10W-30. You won't do harm to mix them, but they're not made to be mixed and you might not get the full benefit of either. I'd try a complete change of 15W-40 in the warm Spring or Summer, and stick with 5W-30 in the winter. Or use 10W-30 in the summer plus a pint of #132 Moly E.P. Oil Treatment. Does your owner's manual allow you to use 10W-30 in your winter weather? If so, that would be a good choice. Ken
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