0-20 all about fuel economy from gm themselves
- Thread starter Waterdog
- Start date
Total BS on oil weight. GM wants thinner oil to reduce overall life of your engine. I believe other manufacturers have designed there engines for thinner oil. Not GM. I have 40,000 trouble free miles on my ZR2 6.2. First Oil changed at 500 miles. Oil changed ever 3500 miles or sooner. Switched to 0w-40. Gained 3-4 mpg. I believe 20w is fine the first couple of 1000 miles. Never go over 5000 miles. I would be extremely curious how many failures because of going over 5000 mile oil changes. Oil is cheap. However how many people put them off because of money. How many people bought a vehicle they can't afford and definitely can't maintain it.
Last edited:
landpilot
Founding Member
- Jun 14, 2022
- 252
- 471
Lake Speed Jr (the Motor Oil Geek) has a really good explanation on oil viscosity, mileage, and the need for GM to hit corporate EPA requirements. GM sucks on a lot of fronts, but this issue is caused by a shitty supplier turning out shitty cranks that didn't meet specs, and then GM taking the shitty way out after not QC'ing the parts. If you picked up 3-4 mpg after 3500 miles, that more likely due to break-in and not switching to 0-40 oil. Were you using synthetic? I've seen that kind of mileage pick up by moving to synthetic after the first change.
Yes, been using synthetic oil from day one. I am not buying bad parts. We tore down a 6.2 with 80,000 miles. Engine was definitely neglected. However, we also noticed the cranks were over tightened. Heavier oil will definitely help. Makes sense better mpg. However, this is not an issue of bad parts. Issue of manufacturing. Lifters go bad because of dirty oil. Again maintaining your engine is the key. You should replace your pvc valve around 30,000 miles. How many even know what a pvc valve is. Extremely high tech autos. Require high maintenance.
Definitely, I don't ever go over 3000 between changes.
Silverado ZR2 Photos
Silverado ZR2 Photos
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