Conventional 10w30 - safe for winter?

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Dec 5, 2014
Hey fellas, normally I wouldn't ask this kind of question but I am really on a fence to change or not to change the oil, I need your help. I drive an Acura CSX with a K20Z2 engine (120k kms / 75k miles). The car currently runs on PYB 10w30 and I have put about 2k miles / 3k kms on PYB. We have been dealing with one of the coldest winters. We've seen -5f so far, in Southern Ontario. I switched to PYB 10w30 two months ago, since I was planning to keep the OCI relatively short (around 3-4k OCI). I wasn't expecting this kind of cold at all, as it used to be much warmer in the last few years. It always sits in an underground garage overnight, not heated but not too cold either. So I haven't changed the oil yet. However, this weekend I will visit a friend of mine and car will stay outside (-25c/-13f) overnight, at least for 8+ hours. I know it's not optimal to run conventional, but I don't want to ruin my engine, and don't want to waste the good oil either. Just wondering, is it safe to keep the oil or should I switch to synthetic tomorrow? Thanks in advance Dan.
My only experience in cold weather was my 02 S10 w dino 10w30 that was parked in -4F over a weekend. It started fine with no abnormal sounds, etc. it also had 30% coolant 70% water that was still in liquid form at that temp. If it’s going to worry you, just change it to 0w30 and call it a winter
The oil is in there. It's a modern oil, so better than the past. It's PYB so it might be a fair percentage of synthetic ... 10W-30 was OK for maybe 30 odd years until they came up with 5W and 0W ... It was the go-to oil for winter from the late 1960's to the late 1990's ... The thing about cold starts is not so much the oil (it is a factor), but mostly is the condition of the battery and the cables ... If the battery is big enough and the cables are too, and clean - it'll go just fine smile
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I had 20w-50 in an engine that spaced 5w-30 and drove it in the winter. When I sold the vehicle the engine had 379000 km and still ran smoothly. 10w-30 is nothing to worry about. As others mentioned make sure the battery is still strong.
If it's going to cause you worries maybe you could change to a 0 or 5w-30 syn now but keep the filter. You're 2/3s into your planned OCI already. A truly frugal person might save that oil and use a quart per future OC until it's gone. Nah, that too obsessive...
Originally Posted By: dgunay
I switched to PYB 10w30 two months ago, ...........but I don't want to ruin my engine,
How do you figure 10W-30 PYB is going to ruin your engine? It's not THAT cold. If you'll feel better, drain it into a clean pan and save it for a buddy with a car that uses oil.
I wouldnt worry if your battery is in shape. Do you have a block heater? (Guessing you dont) Either way, I wouldnt change it for one overnight stint alone. Leave it alone.
Thanks for all input (including troll posts lol) smile Battery should be in a good condition, changed in 2016. It's an OE Acura battery. I don't have block heater, and I cannot use one without moving out, because there is no power output in my parking spot.
Just leave the PYB in the engine for this OCI. I live in the GTA and I never run 10w-30. Always a 5w-20 or 5w-30 full synthetic in this weather. For our American friends, 0W-30 or 0W-20 aren't cheap and easily found at every Auto parts store in Canada. You usually pay more for that grade of oil up here. When Walmart Canada has it's oil specials it's usually only for 5w-20, 5w-30 or 10w-30 (10w which is a rarity up here).
PYB 10W30 specs : CCS @-25*C cP 6,200 (limit 7,000) MRV @-30*C cP 23,000 (limit 60,000) Don't worry about oil pumping. Leave it there.
It's safe, just not ideal. Forty years ago, that would have been the best option. Today, there are more suitable option. I wouldn't rush to change it, but there's simply nothing wrong with running 5w-30 year round to avoid this conundrum.
10w30 is fine. Don't buy into all this cold start mumbo jumbo. Cars ran all year long on 10w40 and 20w50. It's just the new generation that believes it can't be. Worry more about fuel. When it gets down below 0 fuel does weird stuff. Maybe with the new ethanol it will be better since dry gas. I d just keep your tank topped off. Your battery will either start or not start not much you can do there. I lived in the mountains of Pennsylvania for 35 years. I seen -40 with the windshield, I know cold and I ve started cars on 30 HD without incident. It won't hurt a thing.
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