Rotella Oil

30-9

Well-known member
Hi all

I recall reading on here that Rotella 15 40 was a good oil for our flatheads.

So I was in the auto store today and went over to the Oil area and picked up a bottle. It read it's for diesel motors.

So did I mis-read the post or is Rotella 15 40 diesel oil good in a flatty?:D
 
In my opinion, no. you did not misread. I use it in My '51 Merc. with a flathead, I also use it in my '30 coupe with a Y-block. it is a very good oil.
 
I do not know this positively, but i was told by a mechanic years ago that you could use diesel motor oil in a gasoline engine but you could not use gasoline engine oil in a diesel.
 
I use Rotella oil in my 1940 Coupe per the recommendation of a local flathead specialist.
This week I carried my 1966 Mustang with 289 to Ford Dealer for free oil change that I won as a prize in a recent Mustang Car Show. The dealer recommended Rotella 15W/40
for my car. I agreed. Will see how it performs in the Mustang.
 
I use Rotella T 15/40 in both of my YBlocks. One has gone from coast to coast twice. No problems. I wish I could say the same for the rear main seal.

ZDDP right up there.
 
Guys,a word of caution here about using a modern high detergent oil in older engines that were designed to use non-detergent oil. Namely,DO NOT use high-detergent oil in a older engine that has has ran non-detergent oil all it's life and has never been rebuilt. If you do,it will bust loose all the sludge and clog up your filter and your oil passages. The result will be your oil pressure will drop to zero. If you are lucky,you will notice this before bad things happen and will stop the engine,drain it,remove and replace the oil filter,fill the engine with 30 or 40 wt non-detergent oil,and then run it for a while at home until you see the oil pressure start to drop again,and then replace the oil filter again and add a quart of non-detergent 30 or 40 wt oil. Repeat as necessary.

By all means use it if you have a engine that has been hot tanked and rebuilt. It's much better oil.
 
Read this before wasting money on Rotella. I use Valvoline
Cummins Blue in all of my diesels and some off the flatheads.
This is much better than Rotella I like the Molly as well as the
Zink. G.M.
 
Last edited:
Back
Top