it's a '98 3.8 with 97,000 miles. as far as i know conventional oil has been used thus far. should i switch to synthetic?

 

I don't see it being worth the added cost, but that's just me. I have heard others say that their engine used oil with synthetic, and not with conventional. I think conventional is all a person needs, as long as you keep it changed AT LEAST every 5,000 miles. I would go with Pennzoil or Wolf's Head 10W30. (They are actually both the same company now) 3.8 GM motors are super reliable, and I don't see a problem with you getting 200+ thousand miles with proper maintenance.

 

Pennzoil, supposedly is poor quality oil... don't know why, just lots of ppl have said this

higer mileage cars would 'use' up more oil, if moved to synthetic, as it 'finds' leaks, it is more viscous.... so that may be something to consider

cost is not any more going synthetic, it costs about twice as much, but lasts more than twice as long... thus, cost is actually less,

i switched at 64k kms (kms not miles), good decision for me, as i drive lots, but at 100k miles, i think its too late, any added protection to the engine is probably not necessary now, the damage has been done... and you dont want any leak headaches

 

That is true about the synthetic finding leaks that conventional don't. Motor oil is a funny thing......it's like brands of cars, whoever you ask will tell you something different, as fas as what oil is best. Realistcally speaking, there is probably not a whole lot of difference in motor oil these days. They have all improved from years past. I didn't know before, but like I said Pennzoil, Quaker State, and Wolf's Head are all the same company now. I have heard both good and bad reports about Valvoline & Castrol, so it just goes to show you that it's all a personal preference thing.

 

I would definitely agree, their is alot of diversity in opinion when it comes to these sort of things. As for the Pennzoil issue, I used it religiously in my old third-gen bird and my old Cavalier z-24 and it never gave me problems and the Cavalier had 140K on the clock and the bird had 95K. Currently, in my Grand Prix I am using Valvoline Syn-Blend and in the Z-28 good ole Mobil 1 synthetic. Personally, if you want to switch to synthetic, it is up to your pocket book. In my area, the stuff is going for 5.50-6.00 a quart so it can get pricey.

 

Depends. It depends on where you live, the type and amount of driving you do and the condition of your car.

For me, I live in California where even the winter temps don't drop below 30, I drive 60 miles a day (95% highway) and my engine burns/leaks virtually no oil. I don't need synthetic, but I choose to use it and typically do 8k oil changes.

I've paid for oil analysis and I've shown better wear numbers with synthetics, so for me the extra protection (even on extended drains) is worth the extra $10 per oil change.

What are your conditions?

 

Get Castrol GTx-Startup 10w-30 or 10w-40 best **** out there, its dino oil and has a good name.

 

Penzoil changed formulation after it also aquired Quaker State and Shell. Penzoil is a Hydrocracked motor oil, the best you can buy as far as dino oils go.
Only 3 manufatures actually Hydrocrack their oils. Conoco, Penzoil and
76. Motorcraft was made by Conoco, but since its bidded, I think 76 took it over recently. I have tried using Mobil 7500 but so far I am not impressed as it does not feel slippery ater 2500 miles. I think I will return to Motorcraft or Penzoil.
Some companies like Valvoline, Havoline, Kendal and many other major brands including Mobil, hydrofinish theirs to purify it. Its also cheaper to do it that way. Stay away from Parrafinic blends, which most house brands are, including Wolfs Head, as they can no longer meet newer API service requirements.

I use 5W20 grade. Thats the only grade grade I have used since I bought it 3 years ago with 58K miles, now at 110k miles, it uses zero oil and runs great. I tried Castrol 5W20 and will never touch Castrol ever again. I have been told Castrol has up to 20% recycled oil blended into it, but I cant find confirmation of that, also. I burnt it up after 1500 miles. I hope not to have talked your ears off here.... -Tim

here is some interesting oil info....
www.bobistheoilguy.com

 

You did know that Quaker State, Pennzoil, & Wolf's Head are all owned by Shell oil company right?? It's true. I can't see the Wolf's Head being a "worse" oil than Pennzoil, when they are a joint/merged company, and have been since the 60's. As for the API ratings, I currently have Wolf's Head oil in the garage, and it has the star symbol right on the container, that says "meets or exceeds the latest SL API service rating". It also says, protects better than SJ oils, and engine life is extended.

Wolf's Head is great oil, no way around it!

 

www.bobistheoilguy.com

 

Penzoil, Quaker State, Shell and Wolfs Head are all still made by the same processing plants as before the merger. Quaker State has still yet to be able and produce a SL certified 5W20. SL service Rquirements are the newest and are about to be replaced by SM requirements. I always have ran a 20W start up viscosity and either a 5W or 0W operating Viscosity.Penzoil is currently (2002) the only oil in the coperation that is Hydrocracked.-Tim

 

I'm not so sure what you mean by "paraffinic blends" as all Dino oil is about 45-60% Paraffins and 20-30% Naphthenes. Paraffins are a /good/ thing. Your synthetics are basically a PERFECT PARAFFIN with no Aromatic structures (bad) like the dino oil has.

You can refine a dino oil to remove most of the aromatics by the hydrocracking procedure, but it is still NOT as good of structures as a PAO oil (perfect).

So every oil is paraffinic. THere are some naphthenic oils for compressor applications etc... (Diesters, Polyolesters)...

As long as your not using 1qt every 1000 miles I would switch to a PAO synthetic and do oil changes every 10,000-15,000 miles.

Don't let people sway you saying they can run their dino oil and change it every 3,000 miles and save money. That is not the issue. The issue is if you have any knowledge about how your engine wears you will realize that 90% of the wears occurs after NEW OIL (DIRTY) has been introduced into the system. After the filter cleans it up it is alot cleaner and the wear drops off. If you change your oil every 3k you are going through that wear cycle 3 times as often as when you run a synthetic till 12k.

Synthetics being a perfect structure have excellent oxidation properties and they just retain their lubrication properties longer under the same conditions period.

Your VI index is also improved which will help on cold startups as well.

Synthetics (IV - PAO) are the /only/ way to go, IMO.