# 5W30 vs. 5W-50



## PunchIt (Dec 24, 2002)

The last two times I have changed my oil with either BMW 5W-30 or Castrol Syntec 5W-30 I have gotten the "yellow" oil light. It happens within 2500 miles of changing the oil. 

When I use Castrol 5W-50 oil I never have this issue.

I know BMW puts 5W-30 in the cars, but could this be too light? Am I burning oil?

When I let the car sit overnight on level ground and then check the oil level first thing in the morning, according to the dipstick, the oil level is perfect.

However, if I run the engine for a little big, turn it off, let it sit on level ground for 5 minutes and re-check the oil level, then it is almost a full quart low.

I know that some of the oil will stay up in the heads and around the engine, so that is why I was taught to check it in the morning, after the car has sat for about 8 hrs. That way you get a more accurate reading.

Anyone have any ideas why I get this re-occuring light?

DM


----------



## The HACK (Dec 19, 2001)

BMW suggest you check your oil on a flat surface after the engine has been warmed up and sat for about 10 minutes, not overnight.


----------



## nate (Dec 24, 2001)

The HACK said:


> *BMW suggest you check your oil on a flat surface after the engine has been warmed up and sat for about 10 minutes, not overnight. *


Yes, check the oil HOT

and, I would use the recommended oil weights


----------



## Kaz (Dec 21, 2001)

To get consistent readings, I always check the oil stone cold, and make sure the level is a bit on the high side.

And even if something like 5w50 (I didn't even know that grade was possible) was recommended, I'd never use it as that kind of spread would require too many polymers for comfort.


----------



## Artslinger (Sep 2, 2002)

Shouldn't you check the oil when it is up to operating temperature, and after the car has sat for 5-10 minutes. I thought the BMW dipstick compensates for all the oil not draining back.


----------



## Kaz (Dec 21, 2001)

Artslinger said:


> *Shouldn't you check the oil when it is up to operating temperature, and after the car has sat for 5-10 minutes. I thought the BMW dipstick compensates for all the oil not draining back. *


That's what BMW says but I want CONSISTENCY and I don't feel you get that from the procedure BMW recommends.


----------



## Artslinger (Sep 2, 2002)

People check their oil when they stop for gas, when the engine is warm. So Manufactures recalibrate the dipsticks to read correctly in a warm engine, when the oil has heated up and expanded. 

The amount of oil at the top of the engine wouldn't be enough to make any significant difference... about eighth to a quarter of a quart depending on the engine.


----------



## Kaz (Dec 21, 2001)

Artslinger said:


> *People check their oil when they stop for gas, when the engine is warm. So Manufactures recalibrate the dipsticks to read correctly in a warm engine, when the oil has heated up and expanded.
> 
> The amount of oil at the top of the engine wouldn't be enough to make any significant difference... about quarter of a quart depending on the engine. *


That's not my point. My point is that I want to read the level with the oil in the exact same state every time. Unless BMW can tell me that the rate at which every possible grade and condition of oil will drip down and out of every orfice in the engine is always going to be the same, there isn't another way I could think of to get a convincingly consistent reading.

Because oil consumption is something I'm very paranoid about from my time with my old car, this is extremely important. If all I cared about was whether or not there was any oil in the car and nothing else, I woudn't even bother checking since the car has a low oil sensor and light anyways.


----------



## rwg (May 10, 2002)

Daniel said:


> *The last two times I have changed my oil with either BMW 5W-30 or Castrol Syntec 5W-30 I have gotten the "yellow" oil light. It happens within 2500 miles of changing the oil.
> 
> When I use Castrol 5W-50 oil I never have this issue.
> 
> ...


How long is "run the engine for a little bit?" It takes the oil significantly longer to get up to temperature than it does for the coolant to get up to temperature. It takes FOREVER for oil to heat up at idle engine speeds. If you are running the car for five minutes in your garage and then re-checking, you are not getting anything close to an accurate reading.

That doesn't explain the problem with your light, though.


----------



## PunchIt (Dec 24, 2002)

Kaz said:


> *To get consistent readings, I always check the oil stone cold, and make sure the level is a bit on the high side.
> 
> And even if something like 5w50 (I didn't even know that grade was possible) was recommended, I'd never use it as that kind of spread would require too many polymers for comfort. *


The reason why I used Castrol Syntec 5W-50 was because I went to two driving schools and an auto-x out in LA when I had about 4000 miles on my car. I was driving at speeds over 100mph and pushing the engine really hard in 100+ degree weather. I remember at one point sitting in the pits after a run at WillowSprings and the temp was 112 F.

I just felt that 5W-30 was too light an oil. I asked around a few dealerships and talked to some guys who raced BMWs and they all said that 5W-50 was fine for the car.

Kaz- I agree with your reasoning with regards to consistency. That is why I have done it in the morning when stone cold as well.

rwg- running the car for a "little while" is about 25 mintues down the highway to work. Then I recheck the level when I arrive. I figure the oil has reached proper operating temp at that point.


----------



## Artslinger (Sep 2, 2002)

Kaz said:


> *That's not my point. My point is that I want to read the level with the oil in the exact same state every time. Unless BMW can tell me that the rate at which every possible grade and condition of oil will drip down and out of every orfice in the engine is always going to be the same, there isn't another way I could think of to get a convincingly consistent reading.
> 
> Because oil consumption is something I'm very paranoid about from my time with my old car, this is extremely important. If all I cared about was whether or not there was any oil in the car and nothing else, I woudn't even bother checking since the car has a low oil sensor and light anyways. *


Of course you can check the oil when its cold. The dipstick will not read correctly. I'm sure you're smart enough to know that... but is every average BMW owner?


----------



## ObD (Dec 29, 2001)

Daniel said:


> *Anyone have any ideas why I get this re-occuring light?*


Your oil level is low. Sounds like whoever does your oil change is shorting you a quart. I'd bet the deficiency is caused by the new oil filter. I think it holds about a quart. They are not checking the oil level after filling and running the car for a few minutes.


----------

