Oil for my classic Cadillac?

[mojogator]

Hey guys, I've spent several hours here researching and have learned a LOT, I also have more questions than ever - ha ha.

I have a '55 Cadillac coupe powered by a 1970 Cadillac 472. The engine is basically stock and with unknown mileage.

I'd like to hear some oil recommendations - as per the sticky, here's some info -

I live in the middle Tennessee area and it does get hot here. This is a HEAVY car and has A/C.

The car will be driven mainly in the warmer months, more precisely April thru October. I drive it mainly as a cruiser, with the occasional throttle smash. I drive it both on short in-town errands and on the interstate to shows a couple hundred miles away.

I think the original owners manual called for 10w40.

I do have a couple of oil leaks but new gaskets are on the to-do list. AFAIK it's not 'using' any oil, no smoke, etc. No other major mechanical problems.

I'd like to hear your input as to brand, viscosity, additives, etc. FWIW I normally use Valvoline or Castrol in my 'project cars'

Thanks...

 

[Bgallagher]

I say try Quaker State Defy in the 10w-40 flavor. It's rated SN and is a synthetic blend with a good dose of zinc. Get a good oil filter (Pure1 etc.) and enjoy

 

[Boss302fan]

Rotella

 

[user52165]

Not really a concern. Any oil sold now is lightyears ahead of what it was spec'd for. I'd be more concerned with what (how much) has to go into the gas tank.

 

[QuietPortage]

Rotella T Triple 15w40
Mobil 1 15w-50
Mobil 1 10w-40 HM

Pick your poison. I'd suggest running whatever you pick for 3k and doing a used oil analysis.

 

[Rob_Roy]

If you need parts/gaskets call these guys and ask for their opinion on the engine oil at the same time: http://www.cad500parts.com

 

[MetalSlug]

I would say QS defy too, with seal condition and it cheap

 

[Rand]

not to jump on the bandwagon but you will want a higher zinc oil in that engine.

QS defy 10w40 or HDEO's(15w40) are easy to find and would work well.

 

[ARCOgraphite]

15-40 has no to limited apps in passenger cars, Any dino Motocycle 10w40 "4T" will do fine (Castrol, Valvoline) as probably will the new QS Defy. I would avoid "synthetics".

 

[D189379]

Mobil 5W20 just to be different.

 

[NateDN10]

Originally Posted By: D189379
Mobil 5W20 just to be different.

And for no other reason.

 

[daves87rs]

Originally Posted By: Rand
not to jump on the bandwagon but you will want a higher zinc oil in that engine.

QS defy 10w40 or HDEO's(15w40) are easy to find and would work well.



This.

 

[dave1251]

You will be fine with any conventional 10W-40 as long as your engine is stock. You may be able to use a 5w30 but I would not use a 5w30 without analyst and a tune from a expert in this field. A 5W-40 or 15w40 HDEO would not hurt either you have plenty of options just use the one you are comfortable with. What is the current fill in the crankcase or what oil did you use before? Valvoline and Castrol are very good oils and you can use either and rest easy. Also thank you for keeping a piece of American history on the road!

 

[ARCOgraphite]

Many older cam in block amaerican iron Vee Eights have a valve lift around 0.4" and 0.05" duration of < 205 degrees which is a mild cam ramp with low tappet loading. Still, it'll be unserviceable with << 120K miles regardless of ++ zinc or zinc lite. Moly may be the answer.

 

[D189379]

Originally Posted By: NateDN10
Originally Posted By: D189379
Mobil 5W20 just to be different.

And for no other reason.


And because nobody will come up with a "proven" reason not to.

 

[mechtech2]

10-40 or 15-40. the 15-40 HDEO is what I'd use.

BTW,
The cooling system is not made for that engine or AC, so make sure you have a large radiator, and good fan and shrouding. Fan shrouding makes or breaks a cooling system.

 

[SS1970chrysler]

I run many engines of that vintage and older with a good 15w40. Just my $0.02

 

[67lemans]

QS Defy in 10w30
or an HDEO in 10w30 or 15w40

That is what I run

 

[fdcg27]

IIRC, GM was no longer specing 10W-40s in 1970, and was specifically warning against their use.
The original requirement for that engine was probably 10w30.
This is a pretty mild engine by any standard.
The Caddy engines made their power at low revs, since they were certainly of the big displacement school, and had modest specific output.
I think a conventional 10w30 would be okay in this engine, although a modern 10W-40 or 15w40 might be better.
Any oil you'll put in it now is far better than the best oil that could have been found in 1970, though.
Having said all of the above, if it were mine, I'd give it either Mobil 1 High Mileage 10w40 or Mobil 1 15W-50, or at least Maxlife SB 10W-40.

 

[Nickdfresh]

Any name-brand high mileage 10w30 or 10W-40...