are these oils any good?

[Carguy80]

i have gm goodwrench 5w30 and 10w30 and havoline 5w30 available.they are all conventional oils.which of those would be better for my car?my car is pontiac firebird 92 3.1 v6 112500 miles on it.i drive temperatures between, +20f. to +80f.(-7c.to +27c.)thanks.

 

[m2200b]

I'd use havoline 5w30.

Are those last two years or prior owners miles just short trips. If not
I don't see your concern on sludge for this engine. In the US, Goodwrench would be EXXON/Mobil sourced so you can look at EXXON or Havoline performance in the oil tests for the GM 3.1.

What were your semi syn choices in Sweden?

 

[Carguy80]

all synthetic blend oils that are normally available in sweden, are 10w40.i have been usually driven about 20-50km. a day.i have changed my oils every 3000miles/5000km.

 

[KJA426]

What about Pennzoil or Castrol High Mileage 5w30, 10w30, or 10w-40?

 

[Carguy80]

i think they sell here pennzoil too,but i think they are conventional 10w40 and blend 10w40.castrol has a highmileage oil but i think it is little bit a too thick for me,it is conventional 15w40 oil.im sure that i stick with my dino gm 10w30 or i try 10w40 shell helix synthetic blend