correct oil

[longtops]

What is correct oil for my d34,some straight 30 weight,some say 20w50.What say the experts?

[Niel Hoback]

As you can tell from this post, I'm not an expert at anything, but,,,, I have been using recycled 10w30 from my Buick for about ten years now. It must be good enough. Any oil out there is better than what these cars were using when they were new.

[RobertKB]

I run 20/50 in my three flatheads and they seem to thrive on it.

[oldmopar]

I use 5-30 in everything old and new seems to work for me. If it is burning some oil you may want to go with a heavier oil, maybe straight 30 if you are in a warm climate

[martybose]

I've pretty much settled on Rotella-T 15W40 for mine. It seems a good compromise compared to the other choices, and being a truck oil it has slightly more zinc than some of the others (although maybe not for much longer!).

Marty

[Reg Evans]

After you have drained the oil from the oil pan I would put my finger in the drain hole and see what's on the bottom of the oil pan. If it's clean I'd use a multi grade detergent oil. If there is a layer of sludge on the bottom of the pan I'd go with some 30 or 40 weight non-detergent. If the dirty gritty sludge it there you don't want to loosen this up and back into the system.

[Young Ed]

To add to what Reg said where a latex glove or something when you do that. The sludge is at least partially made up of unburnt lead from old leaded gas.

[Captain Neon]

Yes, the oil discussion. I use Rotella T 15w40 and I top off with Havoline 20w50.

[captden29]

i use rotella 30w. i use less oil with this than any other brand or weight. my flattie has 110,000 miles[original] and about 95 to 100 psi per cylinder. i switched to it for the zinc and got the added bonus of less oil burning. every engine is different. try it, you might like it. it is true though that almost any oil made today is better than what these engines got back in the day. i used to use recycled oil in my old 50 dodge and it ran fine on it. i use detergent oil. dennis

[longtops]

Hello captden29 I had purchased rotella 30w to use in my 50 coronet but decided to ask before I changed the oil.The car only has 52 thousand miles on it and I waned to be sure.Thanks all,I think I have made my decision with your help.