Thought I might as well change oil in my girlfriend's 2001 Accord w /4cyl VTEC while I was installing engine block heater. I put 10W-30 MOBIL 1 Syn [out of habit] in it and I suppose it should have been 5W-20. We live in Springfield Missouri, it is going to be cold as *%#@ for a couple days. Should I change to 5W ?? If i have to drop the 10W30 I will waste $25 of syn oil, still cheaper than ruining an engine. I need some advice QUICK !!!

 

You'll be okay. Just remember to put in 5W20 next time. I've seen 5w30 cars switched over to 10W30.

 

I hear that 10W30 is better for the winer because it keep the motor warmer

 

lol

 

Follow this chart, you are supposed to go by the ambient temperature in the area you live in.

OP, you'll be fine make sure next time you use 5w-30

 

I've run that exact same oil in my accord in MN in the winter and haven't had problems (and it gets REALLY cold here). I prefer a 5w30 for the winter here, but it survived without any lasting effects. I worry less about the synthetics in the cold.

I generally would just make sure the car warmed up a bit more than usual.

 

You'll be fine. It's not that big of a deal. How cold does it get in Missouri? I live in MA and I bet it's colder up here than down there. The only reason you would want to use some lighter weight oil is because it will be easier on cold starts in the winter.

 

You should be fine (as most have already said). If you are truly concerned, just make sure that she warms up the engine before driving.

 

You will be perfectly fine. It is a winter oil anyways (as all oils are now, that is what the "W" stands for, No it doesn't stand for weight like some people think, it stands for winter). Plus the fact that you went with synthetic, you will be absolutely fine. You could honestly get away with running thicker oil then that, although i don't recommend it. I run 20w-50 in my Accord, but thats because it leaks and burns oil really bad, and the thicker oil doesn't leak out as fast. It starts up and runs fine, even as cold as it has been here lately.

Just to be clear, don't run 20w-50. As stated, I'm only running it cause my engine leaks badly.

 

[QUOTE=ubercerealkiller;40903127]It is a winter oil anyways (as all oils are now, that is what the "W" stands for, No it doesn't stand for weight like some people think, it stands for winter)./QUOTE]

This is kind of correct. I say kind of because you just made it sound like this oil should only be used in the winter.
That number that you read 5w, 10w, 20w, etc just means that on the coldest day of the year, your oil will act like a 5, 10, or 20 weight oil, depending on what you have. The second number means that is the weight of the oil when temperature are at or above 100*C. I would still go with a 5w-30 in the winter, or maybe something with a lower winter weight just because you want an oil that will flow easily on a cold start.

 

^Simkin314 approves of this message which is brought to you by accord_raffi^

 

As long as theres oil int here you are good!

 

Good thing you used Mobil1. A convention oil would turn into syrup and make starting difficult.

 

You will be just fine. Esp with a block heater. just switch back to 5 next time. You have all things in your favor. Not really subzero enviroment, synthetic oil, block heater.