Garrett Powered Posted April 3, 2008 Report Share Posted April 3, 2008 castrol used to be good but now they use the same base as all the other ones. like penz, quaker, and the cheap oils. the thing to do is drain the oil, throw on a fram filter, a few quarts of cheap oil, and rinse out the motor a little. you can pull the fuel pump fuse and turn it over a bunch with the starter. then drain that out and fill up with synthetic and spin on a fresh ac delco filter. gottsta have my synthetic to run in the turbocharga. Quote Link to comment Share on other sites More sharing options...
88red4cyl Posted April 3, 2008 Report Share Posted April 3, 2008 I posted back on page 2, but I have been reading this thread since. I figured that I would chime in on oil weight since everybody has been saying what weight they run.. Not sure what they cap on the 3.4 recommends, but I know the 3100 recommends 5w30.. IMHO, that is a little too thin of oil for a car with a motor approaching 150K, especially when you don't know how it was beat on in the past.. I use 10w30 in mine because it just gives me a little extra piece of mind.. Sure it may drop fuel economy a tad, but at least I know that I have good pressure, plus I would hate to hear the piston slap if I had an even lighter oil as it's horrendous as it is... Others may disagree, but it's just my 2 cents.. Quote Link to comment Share on other sites More sharing options...
hotrodolds Posted April 3, 2008 Report Share Posted April 3, 2008 Remember, though. It's not all about pressure. Volume is critical, too. In cooler weather, the pressure is up, but the volume is slow to get there. Pressure is only indicative of restriction, and only at one point in the system. With the 3.4 DOHC, volume is paramount to engine life. I'd use what the oil cap recommends. GM built the engine knowing it would wear, and have the weight listed for it. Quote Link to comment Share on other sites More sharing options...
Psych0matt Posted April 3, 2008 Report Share Posted April 3, 2008 Remember, though. It's not all about pressure. Volume is critical, too. In cooler weather, the pressure is up, but the volume is slow to get there. Pressure is only indicative of restriction, and only at one point in the system. With the 3.4 DOHC, volume is paramount to engine life. I'd use what the oil cap recommends. GM built the engine knowing it would wear, and have the weight listed for it. they also built it brand new, and didn't know what 15 years of abusive use would be like at the time not that it changes anything, just saying Quote Link to comment Share on other sites More sharing options...
Garrett Powered Posted April 3, 2008 Report Share Posted April 3, 2008 Remember, though. It's not all about pressure. Volume is critical, too. In cooler weather, the pressure is up, but the volume is slow to get there. Pressure is only indicative of restriction, and only at one point in the system. With the 3.4 DOHC, volume is paramount to engine life. I'd use what the oil cap recommends. GM built the engine knowing it would wear, and have the weight listed for it. ^^^very true and not something most people think about. Quote Link to comment Share on other sites More sharing options...
jake63 Posted April 12, 2008 Report Share Posted April 12, 2008 What I do in all my cars that call for 5W30 is use 5W30 if the temperature is going to be at or below freezing for the next 3000 miles, and 10W30 if it's expected to be above freezing. Many years, no problems. I have read that synthetic is a good idea for the 3.4L, so for peace of mind that's what I use, (Mobil1). I tend to agree with Wally World oil being bladder juice. Quote Link to comment Share on other sites More sharing options...
joey b Posted April 13, 2008 Report Share Posted April 13, 2008 I've switched every car I've owned over to full synthetic and have not noticed any abnormal leaking. 5W30. Quote Link to comment Share on other sites More sharing options...
digitaloutsider Posted April 13, 2008 Report Share Posted April 13, 2008 I would say almost any oil will do. I usually stay away from the absolute cheapest, $1.99 quart. I go for name brands such as Valvoline, Mobil, Texaco, etc. Its more important you change your oil regularly. Any brand name oil is fine. The cheap ass store name shit is like pisswater. It's good for saturns that burn a qt of oil a week and thats it. That's not how private labeling works. Do you really think that Wal-Mart or Pep Boys has a huge oil refinery somewhere to produce just their own oils? All store brands are produced by larger oil companies, and just to name an example, SuperTech is Warren Oil. SuperTech Synthetic is a very nice blend, which actually meets/exceeds some standards that Mobil 1 5W-30 does not. ST Syn meets ACEA A3 "High Performance" specification. Mobil 1 does not. Aside from that, ST Syn and Mobil 1 meet the same important specifications. SPI SM (which is the highest available certification for passenger car oil), ILSAC GF-4 (ILSAC is the International Lubricant Standardization and Approval Committee, which is comprised of GM, Ford, Diamler, and JAMA. ILSAC specification tests in these major areas in engine use: wear and oil thickening, aged oil low temperature viscosity, wear/sludge/varnish test and fuel efficiency ALONG with strenuous bench testing.) and ACEA A1-A2 (A2 meaning "Suitable for most current petrol engines requiring typically specified viscosity ranges and where fuel efficiency is not specified.") So basically, you can bash on store brand oils all you want, but if it meets the above specifications it's fine for use in my engine especially when GM, Ford and Dialmer think so, too. Quote Link to comment Share on other sites More sharing options...
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