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70s Eldorado Engine Oil

Started by Mike Shawgo, July 25, 2008, 02:06:09 PM

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Mike Shawgo

Hello all,

I hate to bring up the much debated topic of engine oil again, but you guys have the real experiences, not just the opinions.   I'm fretting about what oil to use in my 71 Eldo.   It burns oil, but doesn't smoke.  I also hear lifter ticking for just a minute after I start the car after it has been sitting for a few days.  It isn't leaking anywhere on the floor.   Otherwise, it runs great.

My mechanic told me he thinks I should use 20W50 oil in it.  I bought some 20W50 and had a garage putting it in for me, and suddenly noticed I had bought synthetic (Valvoline High-Mileage 20W50 Synthetic).  Actually, the car seems to be running quiet and smoother with this oil, and the lifter ticking seems to have stopped when I start the car, but now I've read some more on the internet and I'm worried that the 50 weight is too heavy, and also that the synthetic might cause deterioratioin of my seals.

Should I stay with the synthetic 20W50 and see if the oil burning diminishes, or should I change it?     I just don't what to do any damage to the engine, seals, or oil pump.

Does anyone have any experience with oil for the 500 engines?   I'm not trying to reduce the costs or frequency of oil changes, I'm more concerned about the engine running smoothly, and avoiding engine repairs down the road.   By the way, the Eldo is a convertible an only driven in warm weather.

--Mike Shawgo

Ted in Olympia WA

20-50 is what I burn in all of mine and it will work just fine for you.

I don't know about the synithetic part of the question but I assume it will be great also, the only down side is the cost.

I would run it till the next oil change (for you I assume this will be next year at this time) and then go to a 20-50 normal oil.

TED
Selling used Eldorado Parts from 1971-1978.  Member Number 25659.

Mike Shawgo

Thanks Ted, that's good to know.

To me, the cost for oil and oil changes is not an issue, if it helps avoid the greater cost of engine problems down the road.  I'd certainly rather pay for good oil and frequent changes than pay for an engine overhaul or replacement later on!

--Mike 

Otto Skorzeny

I was told by my restoration guy and the engine rebuilder to use 20/50 also. I too use it in all my old vehicles. I live in Atlanta so it's not exceptionally cold in the winter but it does get hot in the summer. It works fine.

I put a brand new Ford crate engine in my '79 F100 and was told to use Penzoil. Like everybody on the planet you hear good and bad about virtually every brand oil out there. I used to think Castrol was the only way to go. Now I think as long as it meets the SAE and API requirements and the manufacturer's specs, any brand will do.

Having said that, since the Ford people said to use Penzoil in the new engine, that's what I'm going to use. The cost difference between it and other brands seems like a lot but is really negligable in the grand scheme of things when you consider how much you have invested in your vehicle. I'd change the oil monthly if they said too. It's still cheaper than a rebuild.

As for synthetic? Ther's really no reason to use it. If you rebuild the engine and the engine guy says use it from the start, then go for it. If you've been using regular oil all this time there's really no benefit to be had by switching to synthetic now.
fward

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TJ Hopland

For summer driving no problem. My only concern would be those cool spring/fall mornings/evenings when it may be a bit on the cool side.   I guess that would depend on where you live.  The synthetic would in theory help you on those cold mornings.

Downside I have heard about synthetics on not regular driven motors is it does not 'stick' like regular oils did so extended sitting things are not as well coated.  Also have read that it responds to moisture differently so the marine people don't like it for non regular use stuff.  Dont know if its true, just what I hear. I ran a 5 40 in my deville last winter and it seemed to start cold better.  Did not seem to leak any worse than regular oil did.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Mike Josephic CLC #3877

#5
What these engines were designed to run on was a standard (non synthetic)
10W-30 or 10W-40.  I've used 10W-40 Quaker State in my '73 501 Eldorado
engine since it was new and have never had a problem.  Yes, it's a 500 cubic
inch displacement but the GM term for the engine was "the 501".

The 20W-50 oil was only recommended for those areas in the country where
average temperatures were in the 90-100 degrees F. range (like Phoenix in the
summer).  Otherwise, the 20W-50 is to heavy in my opinion for most uses.

Also, the light "clattering" noise you hear from time to time tells me you may
not be changing the oil frequently enough.  This engine is very sensitive to
dirt -- the best way to keep it happy is to change the oil at least annually,
whether it has been driven or not.  Water and particulate matter settle in the
bottom of the oil pan even just sitting.

BTW, I've owned my '73 since 1973 and the engine runs like the day it was new.
Just had it out today for a drive.

Mike


1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
-------------------------------------
CLCMRC Museum Benefactor #38
Past: VP International Affiliates, Museum Board Director, President / Director Pittsburgh Region

Mike Shawgo

Mike,

On the contrary, most friends accuse me of wasting money on oil changes, because I change it as soon as I get it out of storage in the spring, and then usually twice during the summer, and once more before storing it in the winter.   The way I feel, we usually spend plenty on pampering a vintage car, why skimp on oil changes?

So far from everyone's comments, I think I'll leave the synthetic 20W50 in for the rest of the summer, then change it back to real oil.  I'll have to think about the 20W40 vs. 20W50.   Am I making too much of this?  I just want what's best for the 501.

--Mike

Mike Josephic CLC #3877

Mike:

The info I gave you was right out of the shop manual as far as the recommended
weights to use.  As far as "over doing" oil changes, my feeling is better safe than sorry.

Mike
1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
-------------------------------------
CLCMRC Museum Benefactor #38
Past: VP International Affiliates, Museum Board Director, President / Director Pittsburgh Region