What viscosity motor oil for re-manufactured engine?

Old 08-31-08, 06:21 PM
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What viscosity motor oil for re-manufactured engine?

I have a 92' Ford Ranger XLT. Back in June, I had a re-manufactured Jasper engine installed. It is a 2.9 liter V6.

I live in Phoenix, AZ. The average high/low temperature for July is 107/81. The average high/low temperature for January is 67/45. The mechanic recommends that I use 20W-50 motor oil all year if I stay in the Phoenix area.

I can understand using 20W-50 during the hot months. After all, in July and August we see triple digit temperatures almost every day in this part of Arizona. Does anyone agree or disagree with using 20W-50 all year in my climate. We do have cold mornings and cool days in Phoenix in the wintertime.

My owner manual recommends 5W-30. But my mechanic seems to think the 20W-50 will give this young engine added protection during all seasons.
Old 08-31-08, 07:00 PM
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The 20W50 would be too much in the winter months. I believe a 10w40 would be a better choice for an all season oil. A small V6 like that will get hit on the fuel mileage with the 20W50 in the cooler months. Another possibility would be an additive for the summer months.
Old 08-31-08, 07:04 PM
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use mobil one and it will flow just fine in the colder months. then you won't have to change viscosity summer to winter.

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Old 08-31-08, 07:29 PM
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I like a good 40wt. It seems to be a good year round oil. I have built allot of motors. On a new motor,I will run a lite 20 to 30wt oil and a good filter for the first 30 to 40 miles. Then go to the 40wt with another good filter for the next 3000 miles.

Old 09-06-08, 07:52 AM
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Why second guess the engineers who spent lots of money and test time to make recommendations on vehicle maintenance? If an engine is re-built to the manufacturers recommendations you chould use what they recommend for viscosities. A thick oil will not lubricate bearings that are fitted to very tight tolerances as well the lighter recommended viscosity. You might get the "FEELING" that you are doing the engine a favor and feel good about it but in actuallity you are not helping the engine. Personally I use the proper viscosity of Mobil 1 in everything I own and I don't have to be concerned about outside temps. This recommendation is based on many years of involvement with General Motors Product Service Engineering.

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