So to summarize this thread, we have recommendations to run 0W16 all the way up to 20W50. That about covers it.
Recommended oil for 1975 Cadillac Eldorado 500 CID
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Rotella 30 or 40 weight will work well... Zero reason to use a 50 weight oil.
Originally Posted By: aquariuscsm
^^I forgot about that one. VR1 20W50 would be my recommendation. Plus it`s CHEAP! Isn`t it about $4 a quart at all the chains?
If our Walmarts had VR1 10w-30, I'd have bought them out a long time ago.
Originally Posted By: bubbatime
So to summarize this thread, we have recommendations to run 0W16 all the way up to 20W50. That about covers it.
Considering that the original manual probably recommended every grade available at the time, from thin to thick, depending upon ambient temperatures, this shouldn't surprise you.
^^I forgot about that one. VR1 20W50 would be my recommendation. Plus it`s CHEAP! Isn`t it about $4 a quart at all the chains?
If our Walmarts had VR1 10w-30, I'd have bought them out a long time ago.
Originally Posted By: bubbatime
So to summarize this thread, we have recommendations to run 0W16 all the way up to 20W50. That about covers it.
Considering that the original manual probably recommended every grade available at the time, from thin to thick, depending upon ambient temperatures, this shouldn't surprise you.
Personally, just for [censored] and giggles, I'd run Delo 400 SAE 30, since it's listed in the manual, and it's available.
I've run 425's, and 500's(76&77 Devilles). I'd use either SAE30(HD)or 15w-40 in it. 10w-30 HDEO would be my 3rd choice. The last 3 UOA's I've done on a 70's big block car with lower mileage on modern 10w-30 PCMO's have not been good.
Originally Posted By: SS1970chrysler
I've run 425's, and 500's(76&77 Devilles). I'd use either SAE30(HD)or 15w-40 in it. 10w-30 HDEO would be my 3rd choice. The last 3 UOA's I've done on a 70's big block car with lower mileage on modern 10w-30 PCMO's have not been good.
When it comes to the proper oil for old iron, this guy is the voice of experience.
Lots of people own old stuff for summer cruises.
This guy uses his old iron to drive every day in an area that sees real winter.
His is probably the best advice in this thread.
I've run 425's, and 500's(76&77 Devilles). I'd use either SAE30(HD)or 15w-40 in it. 10w-30 HDEO would be my 3rd choice. The last 3 UOA's I've done on a 70's big block car with lower mileage on modern 10w-30 PCMO's have not been good.
When it comes to the proper oil for old iron, this guy is the voice of experience.
Lots of people own old stuff for summer cruises.
This guy uses his old iron to drive every day in an area that sees real winter.
His is probably the best advice in this thread.
I've been inside more FoMoCo and Mopar than Caddy iron of that vintage when they were newer. Unless Cadillac had some miracle foundry, I'm sure they were roughly similar in machine quality.
But honestly, when you get to these old big blocks and some of the clearances and tolerances they lived with, especially as they aged, I doubt they (or you) would notice the difference between a 10w-30 and a 20w-50. We ran both vis routinely then, depending on compression/wear and how they were going to be used. Most of the factory recommendations of the day for street duty were for a 30.
This one looks to be driven like a parade car, and has a gentle valve train load as they go, so I'm sure a 30, or even a 40, will be plenty fine. BUT I would lean towards an HDEO, as they run much dirtier with their relatively sloppy Rochesters (even in smog tune).
Avoid the synthetics in these older beasts; many used a rope RMS, and would be more prone to leaks. No need for one anyway.
But honestly, when you get to these old big blocks and some of the clearances and tolerances they lived with, especially as they aged, I doubt they (or you) would notice the difference between a 10w-30 and a 20w-50. We ran both vis routinely then, depending on compression/wear and how they were going to be used. Most of the factory recommendations of the day for street duty were for a 30.
This one looks to be driven like a parade car, and has a gentle valve train load as they go, so I'm sure a 30, or even a 40, will be plenty fine. BUT I would lean towards an HDEO, as they run much dirtier with their relatively sloppy Rochesters (even in smog tune).
Avoid the synthetics in these older beasts; many used a rope RMS, and would be more prone to leaks. No need for one anyway.
I ran 20W-50 in my Cadillac when was it 110* F and above outside. The oil wasn't that thick at those temperatures. It gets so hot here in Central California during the summertime that you let your car sit in one spot too long, the tires will melt.
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