Burning oil problems due to dirty piston rings (oil & compression) and prevent catalytic converter problems and keep the oil cleaner for a longer engine life
You engine can be consuming oil due to leaks (You will see oil on the pavement where you car was parked.) and worn valve guides and seals (You see blue smoke or at least smell oil when you first start the engine.) Also a stuck PCV valve will cause it. (They are cheap to replace.). If the problem is caused by dirty and stuck piston rings this technique can save you thousands of dollars! The engine does not have to be rebuilt or replaced!
I scrapped my 2001 Prius because the oil burn had ruined the catalytic converter and being in California there were no aftermarket Catalytic Converters available. For my 2007 I had to buy a replacement Catalytic Converter. I learned this trick late and it cost me I hope you will want to profit from my mistakes!
First go to this page and look at the rings. This is a piston from a 2008 Prius engine with 135,000 miles. The engine was replaced due to burning oil. The bottom ring is the oil ring. Click on the image to enlarge it. You will see small black spots below the oil ring. They are holes that allow the oil scrapped off the cylinder walls to flow back to the crank case. They look black and are full of carbon. Thus oil can not return to the crankcase and it is burned instead!
You can solve the engine burning oil problem for most gas engines. You do not have to replace the engine. If you do this every 100k miles or when you change the spark plugs; you can easily get 500,000 miles out of a well built gasoline engine. Just by pouring engine cleaner (I have used Sea Foam.) down the spark plug holes and letting it sit long enough to clean out the bottom ring, the oil ring and the passages to the bottom of the piston. (It has to seep past the top two compression rings first). You end up cleaning the top of the piston, the compression rings so the oil stays cleaner (longer engine life), and the oil ring and the oil flow passages to the bottom of the piston.
Pictures on this page: 2007 Prius 109k miles: The top left picture above shows the top of a piston at the beginning of a Sea Foam soak and the top right at the end of the soak. Besides the carbon looking thinner the white spot is where the carbon had pealed off exposing the bare aluminum. The main purpose of the soak was to improve the performance of the piston rings. The lower picture to the left shows the same piston after 600 miles with Techron being added to the gasoline. Notice that some of the carbon appears to be burned off. The piston is much closer to the top of the cylinder so the image is different but it is the same piston.
After cleaning the rings the engine runs much quieter and there is no shudder when it starts. The purpose of this soak was to reduce oil burn so the catalytic converter did not go bad at 200 thousand miles and to promote the life of the engine and catalytic converter.. The plugs were not fouled. 8,000 miles after this soak; the oil stays almost perfectly clean after 3,000 miles.
A Prius starts burning oil around 100 thousand miles by about 170 thousand miles the Catalytic converters start to go.
Story of engine where the piston rings were not cleaned soon enough to save the catalytic converter. Now it burns about 1 quart every 3,000 miles and the oil is still fairly clean at 3,000 miles. A HUGE IMPROVMENT! It just got an overnight soak and oil change. At next oil change fast clean out (poured a flush product and ran engine for a few minutes before next oil change) and some Techron.
It was burning about 1.5 quarts of oil every time I got gas and the oil got dirty very quickly and the plugs fouled.
At 282 thousand miles the engine was burning 1 quart every 3,000 miles. So I did the soak again but this time let it soak through for five days. (After 2 days the piston head is bone dry I just did not have time to get to it till day 5.) .1,500 miles later it has burned 1/2 a quart of oil. So no real improvement from the last soak but it is still a huge improvement over the original oil burn rate.
Dirty stuck piston rings are a bad thing because:
- The burning oil will coat up the catalytic converter to the point where it stops working and has to be replaced. If you replace it without fixing the oil burn you will have to replace it again!
- You will loose compression and you oil gets dirtier faster shortening engine life.
- You have to add oil between oil changes.
When it gets really bad:
- You spark plus can foul up.
- You can run the engine oil dry and destroy the engine.
- Have to replace the catalytic converter. Maine, New York and California have restrictions on after market catalytic converters. As a result this can cost you thousands of dollars in those states. Plus if you
- Waste a lot of money on oil and cause unnecessary air pollution.
My 2007 Prius 272k miles on it was burning almost 2 quarts of oil with every tank of gas. I was very lucky I had not ruined the engine by running it dry. I always carried spare oil in the car. IN SHORT I HAD NOTHING TO LOOSE SO I TRIED A METHOD THAT DIRECTLY ATTACKS THE PROBLEM. It worked! I now burning only 1 quart ever 3,000 miles and the oil is staying clean. I tried everything to clean out the Catalytic Converter and although it worked a little better but I could not recover it well enough to keep the ODB II trouble code of P0420 - Catalyst System Efficiency Below Threshold appearing. I replaced the cat but in a state with California emission laws it is very expensive! No matter what state you are in it is at least a two to three hundred dollar expense plus the expense of buying extra oil. In short do this at 100k mils and you can avoid these expenses. If your engine oil is drooping rapidly do this flush.
Basically I poured 4 oz of Sea Foam down each spark plug hole and let sit at least overnight. If you let it sit overnight disable the fuel flow, and spark voltage and crank the engine to get out the Sea Foam in the combustion chambers. If you let the Sea Foam soak into the engine for two days the piston tops will by dry and no need to crank the engine. With either method drive no more than 25 miles with no heavy acceleration and get the oil changed.You can also have your car towed to the oil change place if you worried about the oil being too thin to drive at all.
I have details specific to the engine on a 2001 to 2015 Prius, Prius C, Prius V and Lexus CT200h. There are enough pictures that even if you have never change spark plugs before you will be able to do it.
If you want our detailed instructions just buy anything from this store or you can download it from this page.
"The guide is super helpful." K.V., Los Angeles, California