20-50w oil

Christopher Cline · Sep 26, 2019

anyone ever run 20-50w not diesel rated oil to help with tolerances and leaks on these old engines? I was thinking about switching from 15-40 to 20-50

7.3 Idi
295,000
Non-turbo
All original internals

IDIBRONCO · Sep 26, 2019

That's not a good idea. Our engines are "dirty" running engines. Since they have so much blow by by design, there is a lot of contaminants in the oil compared to a gas engine. Diesel oil had additives that help clean this up better than gas oil does. As for tolerances, the oil pump in our engines is absolutely amazing. It puts out a huge volume of oil. Bearing tolerances are usually a non issue unless it was run low on oil or didn't have regular oil changes.

Eli · Sep 27, 2019

Most 20W-50 is 'S' rated oil, you need a 'C' rated oil for a Diesel - preferably a modern 'C' rated oil ending in -4 for 4-stroke (old Detroits and such need a -2 oil).

Eli

jaluhn83 · Sep 30, 2019

The viscocity change wolnt make much difference, and the lack of a diesel rating will absolutely screw you. Non diesel rated oil will become acidic quickly from the dirty blowby (true of all diesels, not just idi) and cause way more damage than the problems you want to 'fix'

FordGuy100 · Sep 30, 2019

How much blow by does it have, and whats its oil consumption? If its more than 1 quart per 500 miles, a different oil might be something to look into (as long as its diesel spec). Do you have an aftermarket oil pressure gauge?

u2slow · Sep 30, 2019

For something thicker and diesel rated, try SAE 30 or 40.

nelstomlinson · Sep 30, 2019

I used to run a diesel 20W-50 in my VW diesel. It's still available: https://www.mobil.com/English-EG/Commercial-Vehicle-Lube/pds/GLEGMobil-Delvac-Super-20W50

A thicker oil like that will probably be OK for summer. You really don't want to try to start your engine in winter with that in the pan.

MR.T · Sep 30, 2019

I've been using diesel rated 20w-50 amsoil aro for ~10years (or longer). Still starts well at 20F without the blockheater.

nelstomlinson · Sep 30, 2019

MR.T said:
I've been using diesel rated 20w-50 amsoil aro for ~10years (or longer). Still starts well at 20F without the blockheater.

20F ABOVE zero? That's still summer!

Seriously, when it starts to get cold, the thicker oils do slow the starting RPMs. I use the Rotella 5w-40 in the winter, and it does help with starting on those cold mornings.

ttman4 · Sep 30, 2019

Yeah oil can get thick sometimes in winter cold! Remember once back in early '70's cut the end out of old style qt oil can with 30wt, -35F below. Literally had to dig it out with a putty knife like paddle, was just like #2 gun grease. Never forgot this.
When it gets 0 & -10 & -20F & -30F & such round here with my 15-40, I start thinking, hummmm.... I wonder??? LOL

Christopher Cline · Sep 30, 2019

Sorry for the late response, so it has normal blow by, compression is still 400’s it leaks like a siv though, I go through a quart about every tank and a half. If it’s 20F here the it’s a bad day haha it hardly ever gets below 35 in the winter. Maybe I’m january, I have a functioning block heater and leave it plugged in anything below 45F. I did notice it stopped consuming\leaking oil after switching to del o 400 15-40 and two quarts of Lucas additive, the stuff that looks like honey when it pours. Oil pressure when hot at idle is about 6-8 psi at cruising 30-35 psi

lotzagoodstuff · Sep 30, 2019

Any chance you were running Rotella oil before you switched?

20-50w oil

Christopher Cline

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IDIBRONCO

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Eli

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FordGuy100

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u2slow

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ttman4

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