Group 3 syn or Dino

[wn1998]

I have a 92 Astro that is used just for work. I just completed a ARX treatment and now am looking for an oil to stick with. I was using coastal oil from autozone at 3k changes. I was thinking maybe going to a napa syn or Supertech syn and going to 4k changes? Is there an upside to a dino such as havoline or a group 3 syn?

 

[drive it forever]

I would rather use a oil like mobil drive clean, the GF-4 version. Its been rumored to be a group 3 oil on this board. I think the synthetics you listed are of the cheaper, in both price and additive package? I would rather use the havoline/chevron dino's over them first.

 

[Gene K]

Any of the name brand Dinos (Even Valvoline) should go 4000 mi. Chevron or Havoline either one are a good choice.

You might want to look at a oil like Motorcraft 5w30 Synthetic Blend for $1.44-1.74 Qt. It has very good cold pumpability and cold start numbers and should go 5000 mi as easily as the previous oil went 3000 mi.

The new Mobil Driveclean (SM/GF4) likely is a pretty good oil but I have not seen enough UOA to get a good sense of its performance. It does appear though that Mobil may have skimped a bit on the pour point depressants as its Cold Crank and Pump numbers are not as good as most 5W.

The jury is still out as to whether lower VI Group III with a average add pack (MDC) or a Group II+/ Higher VI Group III Blend (MCSB) with a superior add pack will perform best.

Supertech Synthetic likely has a more expensive add package (Remember we cant see all the add pack in VOA) than Mobil Driveclean. I would not hesitate to run Super Tech Syn to 6000 mi.

A Group IV Synthetic like Mobil 1 might go 7500 mi in the 4.3L without to much trouble.

All of the above asssumes a Engine in top operating condition and that the previous oil was not overextended at 3000 mi.

If the van sees frequent short trips where the oil does not reach operating temperature or there is a mechanical problem all bets are off.

As always it is best to do at leat one UOA ($20) at the interval you plan to use to quantify that it is working. Overextending the oil once is unlikely to hurt a engine but continously doing it can be detrimental to engine longevity.

Gene