90% on short trip. What to do to protect engine? - Toyota Yaris Forums

SilverGlow · 12-12-2008, 09:16 PM

90% short trips mean your oil is probably experiencing fuel dilution. In addition, your oil probably does not warm up enough to boil off the fuel, and in addition, the oils is not hot enough to give the best protection; in other words, the oil may not be reaching the optimal operational temperature to maximize circulation up and around all the engine parts. This is where a lighter weight oil provides more protection over a heavier oil. And it is well known that 90% of the wear and tear inside an engine happens during the first 5 minutes of operation, and it is during this time you most want the oil to protect. It full operational temperatures (usually around 200F to 212F) there is little added protection when synthetic is used over mineral oil.

So to mitigate this I would strongly suggest running 5W-20 weight oil, as it will circulate all over the engine internals faster then 30w during the first 5-10 minutes after first start of the day, and better faster circulation during the first start of the day means less wear on the internal parts. I would use synthetic too, as it often contains better additives that will help deal with oil that is fuel diluted.

One last thought: Never equate oil temperature with water temperature. There is no linear correlation, so even if your water is 181F, your oil is not necessarily up to it's expected operational temperature, and often oil takes 20-30 minutes to reach 212F or thereabouts. And it is only after it reaches those temps, will the fuel in the oil boil/burn away.

You might want to get your Yaris on the freeway for 30 minutes at least once a week to minimize the fuel dilution issues.

So in summary:

Use the cheapest synthetic on sale that is 5w-20 or 0w-20. Another benefit of doing this is that you should be able to run your oil 25% to 50% longer over mineral before you have to change the oil.

Until the car is fully warmed up, don't jump on the gas pedel....keep it slow and smooth. You do this, and your engine wil easily reach 300,000 miles without buring oil, or losing much power.

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12-12-2008, 09:16 PM	#12
SilverGlow Banned Drives: 2007 Yaris Hatchback Join Date: Oct 2008 Location: Southern California Posts: 189	90% short trips mean your oil is probably experiencing fuel dilution. In addition, your oil probably does not warm up enough to boil off the fuel, and in addition, the oils is not hot enough to give the best protection; in other words, the oil may not be reaching the optimal operational temperature to maximize circulation up and around all the engine parts. This is where a lighter weight oil provides more protection over a heavier oil. And it is well known that 90% of the wear and tear inside an engine happens during the first 5 minutes of operation, and it is during this time you most want the oil to protect. It full operational temperatures (usually around 200F to 212F) there is little added protection when synthetic is used over mineral oil. So to mitigate this I would strongly suggest running 5W-20 weight oil, as it will circulate all over the engine internals faster then 30w during the first 5-10 minutes after first start of the day, and better faster circulation during the first start of the day means less wear on the internal parts. I would use synthetic too, as it often contains better additives that will help deal with oil that is fuel diluted. One last thought: Never equate oil temperature with water temperature. There is no linear correlation, so even if your water is 181F, your oil is not necessarily up to it's expected operational temperature, and often oil takes 20-30 minutes to reach 212F or thereabouts. And it is only after it reaches those temps, will the fuel in the oil boil/burn away. You might want to get your Yaris on the freeway for 30 minutes at least once a week to minimize the fuel dilution issues. So in summary: Use the cheapest synthetic on sale that is 5w-20 or 0w-20. Another benefit of doing this is that you should be able to run your oil 25% to 50% longer over mineral before you have to change the oil. Until the car is fully warmed up, don't jump on the gas pedel....keep it slow and smooth. You do this, and your engine wil easily reach 300,000 miles without buring oil, or losing much power.