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Discussion Starter #1
My 88 daytona has around 160,000 original miles on it, 2.5 liter standard mitsubishi engine. The engine has never been rebuilt, and it does not burn oil. It still has plenty of pep as I can catch a wheel between first and second (5 speed). What weight is appropriate, 10w 30? Or 10w 40? Thanks.
 

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It's NOT a Mitsubishi engine - it was designed and built right here in the US.

5W-30 or 10W-30 were recommended for most climates. If you live in the US Southwest or FL, I'd run 10W-40 in the hottest weather, and 5W-30 otherwise. I run 5W-30 in MA year-round in my Daytonas.

You can use the oversize filter that was on the slant-6 for more oil capacity and cooling. It's Fram PH-8A or equivalent part numbering.
 

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Discussion Starter #4
Thanks!
 

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I have been using 15W-40 since 1990. That was suggested by a Mopar tech I knew in Detroit that recommended it. There is less wear on the cam because the oil leaves a coating on the top of engine. The oil is thicker and doesn't drain down as easily. So on start up the oil is on the cam and in the lifters. Sounded good...
 

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Not good for cold weather. It won't stay on the cam. It will drain down when hot, and it will not flow when cold. Marc Rozman, Chrysler test engineer, found that at -40F some oils didn't reach the camshaft for 6 minutes. But he found that Mobil One synthetic 5W-30 was the best choice. Now that there are zero-weight oils, there are even more choices for cold weather.
 

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I run 10W30 in the winter and 10W40(if I can remember) in the summer. But that was when the winters were harsher as in when I lived in the north. I run 5W30 synthetic in the Turbo Z.
 

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Not trying to thread hijack, but which would be best of the synthetics?? I'm between Mobil 1 and Royal Purple HPS. Thoughts??
 

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Mobil 1 is made from Group III base stocks and is considered to be a semi-synthetic (though it's marketed as synthetic).

Royal Purple is made from Group IV base stocks and is a true synthetic.

For the overall costs vs performance, I'd go with Mobil 1 If I had to choose between the two.

Either one is fine, just RP is usually more expensive. Whether it's worth the extra expense is up to you.
 

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Discussion Starter #11
When we had our 2005 Tahoe, we ran Mobil 1 synthetic in that and it worked well. Boy, I miss that suv.
 

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I have run 5W50 Castrol Syntech in my '85 turbo for years - pretty well since it came on the market. When I first bought the car, it had been "broken in" on Shell Extrema synthetic - not sure of the weight anymore. I found in really hot weather the idle oil pressure was lower than I liked - the Syntech 5W50 weight helped - then I also added an engine oil cooler - really good pressure after that. I've had a Mopar Performance Super 60 high lift cam in it since '95 - about 40k miles - I have heard issues with wear on those - no wear detectable on mine so I think the Syntech is doing the job well. In my daily drivers I run 10W30 GTX in the older ones ('95 Intrepid and '99 T&C) 10W30 Syntech in the '10 Charger. I have run GTX in the Charger couple times too - I don't really think synthetic is necessary in a normally aspirated non-performance engine. The Intrepid is over 400k kms now and been on GTX since I bought it at 145k kms 11 years ago - compression test last week still 170 lbs all around. The Challenger I run 0W40 Mobil 1 per factory fill - have not found a Castrol product tested to that SRT spec yet. Partial to Castrol cause I have a buddy who works there :) and always had good results with one exception - years ago I tried the turbo on GTX (I think it was branded XLR in Canada in those days) - it turned black from the heat of the turbo bearing in a couple days so I drained it immediately and went back to synthetic.
 
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