Yet another oil question.

In my fleet, 4 cars call for 10w50. Two cars call for 20w50.

The cars don’t get used in winter, but they might in cooler fall and spring weather (say, 10c and above).

All cars hold prodigious quantities of oil. I want to buy a 55 gallon drum of quality engine oil for cost reasons and use it for every car.

Any harm in running 10w50 where 20w50 is specified? I think it could even be of benefit when the temperature is lower.

 

It should be fine ..just realize the oil, although same "50" weight will tend to be thinner at higher temps. If you track or push the car regularly check oil after such use for true viscosity (with a oil analysis) .
Each brand of oil has a different reaction to how it handle shearing and heat ..so my suggestion of test

 

I would not recommend 10w50 in a 10w60 car. The 10w50 will eventually get up to operating temperature and there may be components (hydraulic lifters) that need to have 10w60. Given the cost of the collection and the cost of oil, I would use what the manufacture recommends.

 

He is saying 10w 50 and 20w 50 ..not 60

If it was 50 vs 60 I would agree

 

20w50 is a much thicker base oil than 10w60 (which is thin base stock plus "thick" additives).

If the distribution has a long chain, it will require a thick base stock.

 

No desire to use 10w60.

I have a pair of 2 valve carbureted Countaches that use 20w50 - generally when I find it, it is high quality non-synthetic. Each uses 18l or about 5 gal per oil change (annual changes). Buying by the litre gets to be a pain (and really expensive in Europe).

Everything else I have uses 10w50.

I could buy two barrels I guess.

 

Here is an Ambient Temperature-Oil Viscosity range chart I snagged off the internet years ago that might help put some of the oil questions being discussed here into context:

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