oil consumption on 2002 Chevrolet Prizm

Are there any cheap/reasonable/simple options to reduce oil consumption such as using a onetime/long-term oil additive or convert to synthetic?
I’ve owned the vehicle since it had 108,000 miles on it. Oil consumption then was 1 qt. every 3,000 miles. The engine now has 157,000 miles on it and currently uses 1 qt. around 2300 miles on a fresh oil change. It uses the 2nd qt. by 4000 miles which is when I change the oil & filter. I always use a quality conventional oil that meets API SM, SL Service Classification and manufacturers' U.S. warranty requirements. It also meets or exceeds ILSAC GF-4. I’ve tried several different brands but consumption continues to increase. There are no leaks. I use this vehicle for an 80 mile daily commute with 98% highway speeds. I want to avoid costly (internal engine) repairs. Would using full synthetic help after a few oil changes? If so, what are the precautions I should follow for the conversion to synthetic?

Asked by for the 2002 Chevrolet Prizm
Most car manufacturers will tell you consuming 1 qt per 1000 miles is acceptable for a new car. So technically yours falls well within that limit averaging 1 qt per 2000miles. IMHO even 1 qt per 1000 miles is a bit high for any car. My 1999 Camry also a Toyota like your Prism (Corolla)any uses less than .25 qts. per 3000 miles. Just be glad you use less then these people, high oil consumption is a know problem with your car:
I agree. But I wanted to educate myself on any/all cost effective options out there to reverse the trend. I hear about various oil additives but I’m skeptical. I have a strong maintenance background in aviation but the opportunities are not there to “experiment” like you can in the automotive maintenance arena. I’m hoping I can gather enough information to make an educated decision to reverse the trend. Thanks for the input.
Automotive Restore Engine Restore should take care of that.
I've read up on it before and it sounds like a real good product. Also Petrotech 2000 is a real good oil additive to make your engine run well. Don't know for sure that that is a oil user fixer. If it's due to a stuck valve you could try adding a little rislone to the oil. That fixed it on my 89 acura legend when it started burning.
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use a 20w50 oil lucas oil stablizer 1/2 qt to oil change .change pcvalve make shur vac line coming out of valve cover is open crankcase fiter is good make shur line is nt colaped
Are you saying use 20w50 and 1/2 qt. Lucas stabilizer? Won't 20w50 increase fuel consumption? Is Lucas a onetime/long term solution or needed each oil change?