Mobile One 0W - 40 in M44 Winter

[packratbimmer]

1st cold night in a while and the M44 started like it was the fourth of July. The temp was around 10 F so we will see what happens when we approach zero.

[packratbimmer]

Update: Last night was down to zero. After sitting for a couple of days, the M44 started on the first crank and idled perfectly. I still have the Castrol GTX 5W-20 in there.

No more Mobile One 0W-40 for the car in winter.

[bflan2001]

I'd like to add my 2 cents on this issue. Just some basic knowledge about oil weights I've learned over the years that I feel aren't very well known anymore.

First off, there is a direct connection to the lifespan of your oil and the ratio between its cold and warm ratings. This is because that ratio is accomplished using synthetic additives that break down faster than standard oil (oil rated SAE30, SAE40, etc.). So the bigger the difference, the more additives that are going to break down sooner. For this reason, the ideal oil weight available on today's market is 15w-50. The worst possible oil for longevity is 0w-40. (15/50=.3, 10/40=.25, 5/30=.17, 0/40=0)

Second, oil weights in recent years (including "recommended" oil weights) have gone down across the boards. 20 years ago, 20w-50 was the recommended oil weight for the M42. Today you'll have a hard time finding 20w-50 anywhere. This also happens to have an excellent cold to warm ratio of .4, meaning it will last longer than all the thinner oils. The reason oil weights have gotten thinner is very simple: emissions. Thinner oils require less work to move the internals of an engine, which helps to lower emissions. The only reason you would ever need an oil with a rating lower than 20W is if you planned on driving your car in sub-zero temperatures. Using a thinner oil in anything above 0*F is only going to cause your engine to wear out faster.

All that being said, it's important to let your oil warm up, particularly if you're running a 15W or 20W rated oil. I run 15W-50 Mobil 1 because it's cheap and I'm poor. If I had money to blow I would run Amsoil in a heartbeat.

[M-technik-3]

What are you considering cold? It's -15 F outside this morning and that does not include our wind chill. On Saturday afternoon it was -10 and the wind chill had it down to -38 F Which is brutal.

Reason you have a hard time finding 20-50 is the EPA deems them part of the gross polluter cars. Cars with no cats and so forth it. You can get Mobil 1 20-50 in SJ rating but it's listed as a Harley Davidson oil.

[packratbimmer]

It has been sub-zero for days now and the car starts fine with Catrol GTX 5W-20. Time to discard the manufacturer's website (M1) rubbish and start looking at real world facts.

Hypothesis: The 1998 M44 should use synthetic 5W-30 if a year-round oil is desired and adjustments made from there considering temperature variability due to outside factors such as climate and use (hey, if you have a block warmer and you are attending an ice race - fine).

If one is going by the oil chart provided in 1998, consider it a non-synthetic chart.

BTW: I have no problem with Mobile One in general, but I would be very hesitant to recommend their 0W-40 for winter (or even cooler climates such as San Francisco in the Summer) unless the car needs protection for autocross, track, off road etc.

Just my experience...

[packratbimmer]

Just came in from starting the car at a leisurely 11:45ish AM. Outside temperature is up to 12 degrees F but the lows have been about -10 the last two nights. The car has not been driven since the two cold nights.

Guess what? The engine block was still -12 this morning at 11:4ish. I'm psyched though - the M44 fired up and idled down to a steady 850 per usual. See below:

[TobyB]

For this reason, the ideal oil weight available on today's market is 15w-50. The worst possible oil for longevity is 0w-40. (15/50=.3, 10/40=.25, 5/30=.17, 0/40=0)

???

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[bflan2001]

There's a much more complicated equation you can use to calculate the viscosity index of an oil but that is a quick, simplified way of seeing the level of viscosity improving additives used. The more additives used, the faster the oil will break down. There are many other factors like brand, formula, etc. but these additives are one major factor in how long your oil will last before breaking down and losing viscosity.

[packratbimmer]

Both winters started with new Mobile One 0W-40 so oil age would not be a factor in my case.