5W-20, 5W-30, 10W-30, 10W-40, 15W-40, 20W-50 ..

HOW DO DECIDE WHICH OIL WEIGHT TO USE ..

IS IT BY OUTSIDE TEMP RANGE , TYPE OF ENGINE 4 CYL, 6 CYL, ETC ..HOW OLD THE ENGINE IS ..THANKS FOR YOUR INPUT ..

 

First things first: Turn off the caps lock.

I find that 10w30 works good for most engines. I keep a case around as my all purpose oil. If I've got a worn out engine with real low oil pressure, I'll step up to 15w40 or 20w50 to keep the pressure up. If it's gonna be real cold (below 0F) I'll go to 5w30. If I'm going somewhere real hot, I'll go to a 15w40. I find that 5w20 is too thin for most things I run. No reason to run it other than the warranty, which I haven't had to deal with, no new vehicles.

 

I BEING USING 5W30 IN MY F150 V6 .. WHAT FORD RECOMMENDES BUT LIVING HERE IN CUBA NORTH (MIAMI) I WILL SWITCH TO 10W30.. IT DOES GET HOT HERE BUT WHEN I THINK OF EXTREME HIGH TEMPS IT WOULD BE MORE LIKE NEVADA OR ARIZONA ..

 

You use what the manufacturer recommends. Or, do your research (there are a few sites like www.bobistheoilguy.com) and go with what you think is best. I switched to Mobil1 10W30 on Sunday after using Mobil Drive Clean 5W30 (manufacturer recommended). I went with slightly heavier weight because of the "thinning" properties of synthetic. Basically, you can use 10W30 in just about any gas engine and be fine.

 

Best place to look is the user manual or a Ford webpage if there is one for this. In general...

In Florida I wouldn't worry as much about the ##W part versus the XX part of the ##WXX rating. In Florida I would guess a 30 weight is minimum. In summer you might go with 40 or 50. So.... I would either use a straight 30 to 50 weight oil or a multi vis like the 10W30 as a minimum and maybe up to 20W50 especially in an older engine in the summer. Older engines were also looser tolerance(either factory new or wear) so the weight needed to be a bit higher than 30 especially in summer.

With a synthetic I would go with anything from 5W30 and up. Synthetics are thin even in heavier weights but when they are at temperature they have the appropriate flow and cling characteristics. I have used the 0W30 synthetics and they make my engine a bit noisy on startup so like I said 5W30 and up for me in most cases. I have used 5w30 syn in near zero to well over 100 degrees and towing a trailer with no unusual noise or complaints.

If you can, they usually recommend a low spread in the ##WXX range. This might be old habit but things like 10W40 were not recommended due to the 30 point spread which meant that there were a lot of viscosity improvers in the oil which essentially are plastic which don't lubricate but had a tendency to "burn up" quicker than an oil with a lower point spread. Note that 20W50 even though it has the same spread starts with a thicker base so the 30 point spread is not an issue. This only applies to dino based oils, synthetics don't care.

Good Luck,

Jim Henderson

 

I think 10w30 in warm months and 5w30 in cold months is ideal for most situations involving a gasser. 15w40 diesel rated oil for a large vehicle pulling a load. I am stuck with 5w20 to protect myself from any hassle while under warranty.