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  • avatar MrShift@Edmunds 05/25/12 6:47 pm PST

    Well the laws of physics demand that it either be leaking or burning---there's no other explanation for oil loss.


    If it were burning a quart every 500 miles I'd say you'd be seeing smoke out the tailpipe. All I can suggest that doesn't cost $$$ is a) have a friend follow your car as you go DOWN a hill, in gear, and let off the gas and let the car just slow down, in gear----then ask your friend if he say blue smoke.

    Also you can get the car on a lift and look for a pretty good size leak--sometimes they are hard to spot.

    If nothing obvious shows up, then have a "cylinder leakdown test" done on the engine---it'll cost maybe $100 bucks but it'll tell you for sure what the internal condition of your engine is.

Answers

  • MrShift@Edmunds 05/25/12 6:47 pm PST

    Well the laws of physics demand that it either be leaking or burning---there's no other explanation for oil loss.


    If it were burning a quart every 500 miles I'd say you'd be seeing smoke out the tailpipe. All I can suggest that doesn't cost $$$ is a) have a friend follow your car as you go DOWN a hill, in gear, and let off the gas and let the car just slow down, in gear----then ask your friend if he say blue smoke.

    Also you can get the car on a lift and look for a pretty good size leak--sometimes they are hard to spot.

    If nothing obvious shows up, then have a "cylinder leakdown test" done on the engine---it'll cost maybe $100 bucks but it'll tell you for sure what the internal condition of your engine is.

  • zaken1 05/25/12 7:08 pm PST

    What brand and weight of oil are you using? Have you been adding dfferent kinds of oil at different times? How often has the oil and oil filter been changed?

    I have seen this happen with Toyota engines when they were switched from one type of oil to another; or if too light a viscosity of oil was used.

    If you click the "answer this question" button, respond, and click the "submit answer" button; I may be able to recommend a lubricant change that will improve this problem.

  • redman800 05/26/12 9:08 am PST

    i belive they have been using motorcraft 5w-20

  • zaken1 05/26/12 2:29 pm PST

    Thank you for the information. From what you wrote, I am assuming that when the oil is low every 500 miles; you have Motorcraft 5W-20 added;; and that the oil and oil filter are changed regularly with this same oil type being used each time. Please correct me if the oil and oil filter are not being changed regularly, or if a different oil type is used when oil is added between changes.

    There are basically three different causes that could be creating this problem. One would be that the engine was damaged by overheating when the previous owner had it; and the cylinder head or the head gasket is now leaking between an oil passage and a cylinder. This will cause oil to be drawn into a cylinder, burned there, and pumped out the exhaust. If one spark plug shows substantially more oil deposits on it than the other plugs; that indicates this problem is likely. A shop will have to run a cylinder leak down test to confirm this determination.

    The second possible cause is that the mass airflow sensor, throttle body, air filter, and/or PCV valve have become fouled with dirt; and are now causing an excessively rich fuel mixture to be injected into the engine; which washes the oil off the cylinder walls, where it is then burned, and is pumped out the exhaust. To address this possibility; I would have the air filter inspected and replaced if sunlight does not pass easily through the element; have the PCV valve replaced, and thoroughly clean the mass airflow sensor (using only mass aiflow sensor spray on this part) and the interior of the throttle body.

    The third factor here is that Toyota engine designs work best with a heavier oil grade than most other imports. They will run with the diluted "energy conserving" oils which new car dealers are required to use by U.S. laws; but some individual motors will develop piston rattle, preignition, and will consume this diluted oil far more rapidly than desired. The solution here is to change to 15W-40 oil, in a non energy conserving formula. This will mean having the oil and filter changed and replacement oil added at a shop which is not a new car dealership.

    The best oil to use for this purpose is Castrol or Pennzoil 15W-40. But do not switch back and forth between brands. Choose one and use it exclusively; both when the oil and filter are changed, and when oil is added between changes.

  • remass 04/23/13 6:50 pm PST

    I also have a 2008 Rav4 with 62,000 miles. It uses a lot of oil too. I added over a gallon of oil between my scheduled oil changes.

    The answer to your inquiry is simple. we are victims of the defective Toyota 2.4 liter engine. And 2008 is smack dab in the middle of the time frame this problem existed. Bad matching of pistons,rings to cylinder fit that thousands are experiencing.

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