I have a 1997 Toyota Tercel with 280k original miles. I've been monitoring the number of miles that it burns one quart of 10W-30 conventional oil for a while. The manufacturer's recommended oil is 5W-30, but it burns 5W-30 way too fast. My results have been highly variable, but I still think the data is useful. The level in the oil pan was not the same for all measurements which may have contributed to the inconsistent results. Oil consumption may increase as the oil level in the pan decreases.
From 184k miles to 247k miles I got five results and they varied from 1200 to 2200 miles per quart burned. The measurement I got at 251k and 252k showed that it burned a quart in 900 miles for both results, so something happened to the engine at that point. I have done compression tests myself after 252k miles, and the compression readings were good. So I guess something happened with the valves at that point maybe with their seats. The compression tests were not entirely trustworthy because the compression gauge needle would never peak with both of the gauges I used, i.e., as long as I cranked the engine the needle would continue climbing for some strange reason. But somehow the readings for all the cylinders were very close and within spec, and after several minutes the needle did not drop so there was no leaking. Because of the increase in oil burning after 251k miles I started using Lucas Oil Stabilizer at 40% concentration. The LOS did reduce the oil burning. At 262k, 265k, and 280k miles I got 1669, 1968, and 1627 miles per quart of oil burned respectively.
Lucas Oil Stabilizer is not popular on this forum, so what should I do about the oil consumption? Should I continue using the 10W-30 untreated and burn a quart every 800-900 miles? 5W-40 oil is controversial for several reasons especially for engines designed to use 5W-30, so should I try 10W-40 untreated? I recently started using Castrol High Mileage 10W-30 which does not seem to have made much difference. I'm not willing to have any serious engine work done because I will have the engine replaced for under $1000 with a used one from Japan that has 30-40k miles on it or pay a little more to have the engine rebuilt before spending several hundred dollars for serious engine repairs.
Thanks for any replies.
From 184k miles to 247k miles I got five results and they varied from 1200 to 2200 miles per quart burned. The measurement I got at 251k and 252k showed that it burned a quart in 900 miles for both results, so something happened to the engine at that point. I have done compression tests myself after 252k miles, and the compression readings were good. So I guess something happened with the valves at that point maybe with their seats. The compression tests were not entirely trustworthy because the compression gauge needle would never peak with both of the gauges I used, i.e., as long as I cranked the engine the needle would continue climbing for some strange reason. But somehow the readings for all the cylinders were very close and within spec, and after several minutes the needle did not drop so there was no leaking. Because of the increase in oil burning after 251k miles I started using Lucas Oil Stabilizer at 40% concentration. The LOS did reduce the oil burning. At 262k, 265k, and 280k miles I got 1669, 1968, and 1627 miles per quart of oil burned respectively.
Lucas Oil Stabilizer is not popular on this forum, so what should I do about the oil consumption? Should I continue using the 10W-30 untreated and burn a quart every 800-900 miles? 5W-40 oil is controversial for several reasons especially for engines designed to use 5W-30, so should I try 10W-40 untreated? I recently started using Castrol High Mileage 10W-30 which does not seem to have made much difference. I'm not willing to have any serious engine work done because I will have the engine replaced for under $1000 with a used one from Japan that has 30-40k miles on it or pay a little more to have the engine rebuilt before spending several hundred dollars for serious engine repairs.
Thanks for any replies.