15/40 oil

randyj68 · Post by **randyj68** » Mon May 28, 2012 9:18 pm

Just wondering the pro's and con's or in general opinion here. I have a 390, no clue true mileage, purchased the engine last year so I could drive my old truck around. It's using some oil, will smoke some when I first change the oil but i'm not going to be able to rebuild it for a while. I was curious if anyone has ever ran 15/40 oil, I know its primarily for diesels, but have heard folks using 20/50 in engines that smoke and use some oil, didnt know what the consensus is with the 15/40. Thanks!

hazelnut · Post by **hazelnut** » Mon May 28, 2012 10:17 pm

I buy it in 5 gallon buckets and run it in everything. Never seen any problems with it. Im sure my focus really don't like the thicker oil but it's still running good with 190,000 miles on it.

averagef250 · Post by **averagef250** » Mon May 28, 2012 10:50 pm

I sort of agree. I bought a couple hundred gallons of new Valvoline blue 15/40 awhile back from a craigslist guy who "got a deal on it from work". I think it accidentally found it's way into his pickup at night maybe? I bought it all for $80.

Anyway, been running it everything. Lawnmowers to lathes and air compressors it works pretty darn good.

I used to buy a couple dozen different kinds of oil. Now I just have 15/40 and ISO 46 tractor hydraulic fluid. Sounds a little ghetto I guess, but it seams to work pretty good. I was spending $120/5 gallons for mobil DTE and Vactra 2 for my machines. I decided to try tractor hydraulic for $45/5 gallons and noticed that some gearboxes sounded better, clutches worked smoother.

The money I save on oil I spend on good filters, so I guess it's all a wash.

1972hiboy · Post by **1972hiboy** » Tue May 29, 2012 12:28 am

I use 15/40 in all my FE's. Works pretty well. If i was in colder parts of the country I might use something a lil lighter but here in the central coast of cali its fine. The last two cams I broke in specifically said use delo 400,rotella ect. I think it was because the oil is high in zinc? I could be wrong but if the cam manufacturer asked for it then it was good enough for me.

1970 Hi-Boy · Post by **1970 Hi-Boy** » Tue May 29, 2012 6:05 am

I too use 15W-40 in my 360, a synthetic with added zinc for protection of the older engines. It still starts up easy on cool mornings being synthetic and not thickening. Engines of today have much tighter tolerances that's why they use such a light oil in them.

Kurt Combs · Post by **Kurt Combs** » Tue May 29, 2012 10:26 am

I ran a 15/40 oil in my old 360 and my oil pressure gauge showed a decrease in pressure at highway speeds of 65-70 mph. The pressure seemed to improve with the use of 10/30. I would recommend you change the oil and see what happens. I had the best luck with Castrol GTX 10/30. My experience is, ask 10 people about what oil to use and you will probably get 10 different answers.

mark F-100 · Post by **mark F-100** » Tue May 29, 2012 3:10 pm

Rotella 15-40 is what I use.Good for breaking in new cam also because it has added zinc which is good for our motors.

Whateverman · Post by **Whateverman** » Tue May 29, 2012 5:14 pm

i try to use 20w 50 whenever possible -even in winter,in the last few years lighter weight oils seem to turn into weasel pee in rapid fashion

cdeal28078 · Post by **cdeal28078** » Tue May 29, 2012 8:20 pm

15/40 Rottela in my 460. Works well and will stick with it.
clint

randyj68 · Post by **randyj68** » Thu May 31, 2012 2:54 pm

I always like opinions, unless they are from my wife! Thanks for the responses

eggman918 · Post by **eggman918** » Thu May 31, 2012 4:49 pm

I was told that Wife's dont have opinions only facts

Kurt Combs · Post by **Kurt Combs** » Thu May 31, 2012 5:58 pm

Good thing is wives only know the difference between corn oil and olive oil, not 10-30 and 15-40. Okay, before I get flamed as being a chauvinistic _-hole, I know some wives do know their way around a shop, just not the two I have been married to.

Jarred Hodges · Post by **Jarred Hodges** » Sun Jun 03, 2012 9:59 pm

I run 20w50 supertech in my 390 and it doesn't leak or burn any oil. I tried 10w40 castrol in the truck and it either leaked or burned a quart in a couple months. I never figured that one out

cowbay · Post by **cowbay** » Mon Jun 04, 2012 5:38 am

Jarred Hodges wrote:I run 20w50 supertech in my 390 and it doesn't leak or burn any oil. I tried 10w40 castrol in the truck and it either leaked or burned a quart in a couple months. I never figured that one out

See I run run 10W40 in my 390 and she does not burn at quart at all. Goes back to the old saying different strokes for different folks

tidybowl · Post by **tidybowl** » Mon Jun 04, 2012 7:26 am

I ran a shop for 6 years and tried so many different oils because most of the time somebody was trying to sell me hundreds of gallons. Oil is NOT all the same. I've seen flame tests done and watched oil like Penzoil turn to tar in a heart beat. Our Bumps are like the oil it'self. Their all different. Since most of us are on a beer budget I've found the house brand, i.e. Auto Zone "Costal" has to meet the same specs as the big boys. Choose your weight and buy the cheep stuff. If you change your oil often you have nothing to worry about. That's my wife's opinion. JUST KIDDING

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