Synthetic Motor Oil

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Well-known member
Nov 18, 2007
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I have always used Penzoil 10/30 motor oil. Why Penzoil I really don't know. I have been told that synthetic oil is better and lasts for thirty thousand miles before oil changes are necessary. That is hard for me to believe. I have always changed oil at around five thousand miles with no problems. Does anyone know the truth about the synthetic oil.
I don't know about 30,000 miles. I use Mobile 1 synthetic 5-30 and usually run it 10-12,000 miles. Haven't had any problems.
guys running diesels will do oil ananlysis on it before they change it and some guys typically will go 20000 or more. changing filters and topping off the oil .they dont change it til the ananlysis has it contaminated or the additives are gone.
save yer money and keep doin what yer doin..full syn are very pricey.
Although synthetic oil may still be good for 30K... in alot of conditions it is dirty and needs to be changed at 5K. I change my oil and air filter every 5K because of our severe conditions.

I have ran nothing but synthetic in my current truck and like it.
my current truk takes 14qts and an 8$ filter. sounds kinda pricey for syn..but some guys will slurge. i went 300k on my old diesel ram and it only had reg oil for 5k at a time
30,000 is FAR too many miles to put on a light duty truck that sees continual RPM changes. I myself use synthetics, but change every 10,000 (versus 5000 with dino oil). It saves you a little bit of money, since you've doubled your interval, but a good synthetic won't cost you twice as much as a good dino.

BTW, 10/30 is too light an oil to run in a diesel in the summer. You should be using 15/40.

Naw, I never frequent any diesel forums. When I was in business, I did frequent a couple but quickly grew weary of it. "Never have so many known so little" :) And those that do know quickly get beat down by those who are too small minded to realize that there is a world beyond them and the forums they visit. We used to call those types "ICPs" --> Internet Certified Professionals

hahaaa..keyboard cowboys!! woohoo.. its like on here..just a diff topic. i have learned alot and w/o that forum id have spent alotta money on stuff i didnt need but i have spent alotta money on mod to make up the difference. its a good place to make connections for parts and stuff
I've always wanted to try the syns. but I do the 3K mile oil change and like someone said above it would get a little pricey. I ain't saying it can't be done but I would never run an engine for 30K miles on the same oil. The oil becomes diluted from the combustion process and that fact doesn't change using syns. If I can't get 200K miles on an engine using Penzoil or Quarker State between major work I feel like I did something wrong. JMHO.

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