10W-30 or 5W-30 for 03 M45?

[kankrah]

So a buddy of mine uses 10W-30 during the winter for his motor and 5W-30 during the summer. Does it really matter? Any performance benefits? I use a 5W-30 all year round for my 03 M45. Any thoughts/ insights/experiences ?

[CPJ LB]

does your buddy also have an 03 M45? Where do you and your buddy live?? In cold climates, its best to use a lower Winter (W) rating regarding motor oil. I'm not sure, but I believe the 03 M45 recommends 5W-30, so using a higher Winter (W) rating is not necessarily the best thing to do. By using a higher Winter rating, the oil takes a little longer to get to the engine parts during morning start-ups - especially during the winter months. Rule of thumb, you want to stick with a lower Winter rating especially if you reside in colder climates... in addition, there are some lower Winter rated oils on the market as well -- 0W-30, 0W-40, etc.

The weight of the oil (30 weight) is fine. Just stick with 5W-30.

[kankrah]

Thanks! That's very helpful. We both live in Maryland so even though it gets cold here its nothing like other places in the country. I will stick with my regular 5W-30 then. He was saying the 10W-30 was also good for my V8 Engine but i understand your explanation and it makes a lot of sense. He has an older G20 and uses 10W-30 during the winter and 5W-30 during the summer months.

[CPJ LB]

I think for your friend's motor, it's also recommended to use 5W-30. I would think to use the higher Winter rated oil in the summer instead of the winter.

I wonder if your buddy notices any sound differences during start up (in the winter months). I would imagine some engine clatter at start up (and eventually going away after letting the engine idle) while using the 10W-30 during the winter. Another possibility to think of; by using a higher Winter rated oil, it could put some stress on the oil pump -- especially on an older motor, and in colder weather...

I live in Southern Cali, so we don't get cold weather during the fall...I use 5W-30 year round and have used Castrol synthetic 0W-30 (Euro spec), Mobil 1 5W-30 (high mileage), Pennzoil 5W-30...

In your case, just monitor your oil levels and be safe during the upcoming change of weather

[kankrah]

Right on!

Thankfully i don't have any oil issues. I monitor it pretty often and the levels stay pretty much where it should be. I'm still under 100K but i still use the high mileage 5W-30. My old mechanic once messed up and put a 5W-20 in my car… lets just say i almost killed him haha. My car would rattle at initial acceleration and i was wondering what had happened. But yea after that, I've been very conscious about the type of motor oils I'm using and so I'm also open to expert suggestions on which types of oils are healthy for my engine.

Thanks again!

[NascentHorizons]

I wished I read this sooner. I just did an oil change close to 2 weeks ago and did a Mobil synthetic 5w-30 on my '10 M35. Definitely the way to go.

Also, SUCKS about that 5w-20 incident. lol Glad your car (and your mechanic) survived that one.

[kankrah]

Haha yea i was really upset with him about that one. He's been my mechanic for almost a decade and never had any issues with him when he worked on my honda. I only took the car to him because i had a HORRIBLE experience at the Infiniti dealership. But yea I'm hoping there are no long term effects from that mess up.

[Double E]

Another +1 for the 5/30.
(and great to see another 03-04 owner here!)

[kankrah]

Yessir!!!

[szh]

5W-30 will work fine for most climates in the US ... even in some snow weather like New England perhaps, where it does not get far below freezing usually.

Only consider lighter oils in winter when you live way north in snow Montana or Minnesota country ... or during Canadian or Alaskan winters.

Z