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Discussion Starter · #1 ·
I plan on doing a full service on a car that I just purchased. 09G8GT with a hold of the original owner today but if I can’t just wondering should I use full synthetic oil in the car I know the myths about oil will cause leaks if I run synthetic but those messages were for the old synthetic oil where is new synthetic oil do not have all the additives thatI plan on doing a full service on a car that I just purchased. 09G8GT with 200,000 on the clock. I’m going to try to get a hold of the original owner today but if I can’t just wondering should I use full synthetic oil in this car I know the myths about oil will cause leaks if I run synthetic but those myths were for the old synthetic oil whereas new synthetic oil do not have all the additives that made seals leak. Just wondering if I should switch I mean I doubt it’s going to hurt the car in anyway. Also the car had a code for loyal pressure but after using a scan tool with the car fully hot the oil pressure was 20 at 600 RPM which I don’t think it’s all that bad just wondering what weight oil I should run if I switch to synthetic.
 

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Proceeding responses should be interesting to say the least. Would use a good quality 10W-30 synthetic blend or full synthetic motor oil. Personal preferences are Castrol or Pennzoil high mileage.
 
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Reactions: jonup

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Next oil change, do the 10W-30. You should see the hot idle pressure go up to 25 or 30psi. Safer pressure for spirited driving. Synthetic or regular.
 
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258k miles here, still using synthetic 5w30, might give the 10w30 a try next oil change. Started car this a.m. at 25 degrees outside temp. Very quiet, with no valvetrain noise what so ever.
 

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Local quick change oil shops are interesting after having to use a breaker bar to remove the oil drain plug. Won't even get started on removing the oil filter. Perchance it's merely standard industry practice albeit gesh.
 

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201k and whatever synthetic in 5W-30 is available. I do like the AC Delco filters.
 
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Reactions: DE DORSETT

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I use what the owner's manual recommends.....5W30. I'm at 191K and I switched to full synthetic around 50K. Still rides like a charm. As far as brands, any will work as long as it meets GM standards. I usually go w/what is on sale. And usually, the NAPA brand is on sale.
 
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