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I’ve heard that 15w40 is good for the old ford pushrod engines, is this true? Reason I’m asking is I have a 77 f150 with a 351m 330k miles (I believe) that’s pretty worn out but still runs good. Oil pressure hangs around 0-5 psi at idle and 25 psi at highway speeds. Will 15w40 help this motor hang in there until I’m able to rebuild it?
I run DeloLE 15w40 exclusively in mine, but in the past used 20w50 too. I have read a few here call 351Ms junk, but mine lost enough oil pressure in 1992 that the OEM gauge read zero, I thought it was the sender as it never knocked. I drove it all weekend, watched the Atlanta 500, visited family in western Ga, loaded up and drove over 500 miles home, with a bed full of tools. A check with a real gauge once home showed a max of 4 psi. I rolled in new bearings hoping to get a few months out of it. In 2023 I revisited the bearings for a look, and rolled in a new set. I can't fault the 351M.
I run DeloLE 15w40 exclusively in mine, but in the past used 20w50 too. I have read a few here call 351Ms junk, but mine lost enough oil pressure in 1992 that the OEM gauge read zero, I thought it was the sender as it never knocked. I drove it all weekend, watched the Atlanta 500, visited family in western Ga, loaded up and drove over 500 miles home, with a bed full of tools. A check with a real gauge once home showed a max of 4 psi. I rolled in new bearings hoping to get a few months out of it. In 2023 I revisited the bearings for a look, and rolled in a new set. I can't fault the 351M.
Of course I can’t verify it’s truly 330,000 miles but from what I know about the truck before I got it I believe that’s right and never rebuilt as far as I know. That poor 351 has seen better days but I don’t think it plans on giving up. I’ve put about 2,000 miles on it with oil pressure peaking around 25 psi once warmed up and it hasn’t complained yet so i figure I’ll treat it to some thicker oil and see how long it’ll last. They can handle more abuse than the average motor. I would think twice before I called them junk!
I've ran either 15/40 or a combo of DELO 15/40 and 10/30 XLE in my 300-6 and in my '94 Dodge 2500 V-10 for many years, the Dodge since I got it in 2007, and the Ford since the late 1990's. It won't hurt a thing.
Either change the oil fairly soon the first time or two, or at least change the oil filter, as there will be a good cleaning.
Here's what my '87 300 looks like inside from running diesel oil.
Originally Posted by Chevron Delo-400-LE-SAE-15W-40-Technical-Datasheet
APPLICATIONS Delo 400 LE SAE 15W-40 is a mixed fleet motor oil recommended for naturally aspirated and turbocharged four-stroke diesel engines and four-stroke gasoline engines in which the API CJ-4 service category and SAE 15W-40 viscosity grade are recommended. It is formulated for engines operating under severe service and a wide range of climatic conditions. Delo 400 LE SAE 15W-40 is excellent for use in engines equipped with features like four-valve heads, super charging, turbo-charging, direct injection, shorter piston crowns, higher power density, intercooling, full electronic management of fuel and emissions systems, exhaust selective catalytic reduction, exhaust
Run what you want but you will not see a C designation on any gas car being factory recommendation for oil
It was always CC or CD, CE and CF and now up to "CJ"
None of them (with a C) are recommended for gas engines
Read some more
Show me a gasoline vehicle owners manual that shows that spec
You will not find one
Delo XLE 10w40 is rated for gas and diesel, if you can still find the 10w40. The 15w40 I have left is also rated for SN.
I have used 15w40 and 10w40 oils in both my pickups for many years with nothing to show but a much cleaner engine inside, better oil pressure on the old and worn bearings, and s smooth quite engine.
What's diesel going to do, suddenly cause a rod to shoot through the block or make the engine become a diesel? Diesel oil is some of the best refined and toughest oil you can get, that's why it works in trucks that weigh 80,000 lbs.
In older engines, it will smooth and quieten them up and cut or eliminate oil usage. I've ran it lots of years and lots of miles. My 300 in the Ford and V-10 in the '94 Ram love it.
Anyway, that's my sales pitch. Anyone can run what they want, even kerosene.
I'm running Delo 15w40 in everything I own, and have since 1999 when I bought my first new diesel SD, I have yet to have any issues that are oil related on anything... although when I rebuilt the 351Measly in my 77 F250/4x I used the Valvoline oil for high zinc for the cam break in and 2 oil changes. My 77 F150/4x/351Measly has had Delo 15w40 run in it since I've had it, appx 20yrs, my 66 F100 w/300 same same.
I also have stationary generators at some of my Off-Grid sites that run 24/7/365 that I'm running Delo 15w40 in, one has appx 22,500 hrs, 2 are at appx 10k hrs and another 2 are around 1k hrs, the 2 gens with 10k hrs grenaded themselves around 3k hrs when they were using Amsoil, stationary propane generator specific high dollar oil... they were rebuilt and I have used Delo 15w40 in them since... so that's my sales pitch, nod to Yardbird
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Amazing.
