Grade of oil - Page 2
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Page 2 of 2 FirstFirst 1 2
Results 16 to 23 of 23
500, 472, 425, 368 Discussion, Grade of oil in Cadillac Engine Technical Discussion; Those old engines ran very well on 30 wt except when the outside temp is regularly below 40. Switch to ...
  1. #16
    z06bigbird is offline Cadillac Owners Connoisseur
    Automobile(s): Sedan de Ville, CTS
    Join Date
    Mar 2007
    Location
    San Antonio, Tx
    Posts
    4,771

    Re: Grade of oil

    Those old engines ran very well on 30 wt except when the outside temp is regularly below 40. Switch to multi grade then.

    You will hear engine struggle to start if oil is too heavy.

  2. #17
    cadillacmike68's Avatar
    cadillacmike68 is offline Cadillac Owners Enthusiast
    Automobile(s): 68 DVC, 96 FLTWD Brg, 09 STS N* Platinum, 11 CTS Premium
    Join Date
    Jan 2005
    Location
    Heading back to the sandbox!?!
    Age
    52
    Posts
    986

    What is this about no zinc in newer oils???

    I don't want to burn out the bearings in the newly rebuilt 1968 DVC which does NOT have roller lifters. I'm not too concerned about the 2000 Eldorado with 103,000 miles, I'll just use 10w30 in that car nor am I concerned about the 2005 CTS, but i am concerned about my 1968 and the 1995 Fleetwood with 188,000 miles. I was using 10w30 but with its age, perhaps I might need to use 10w40 (I think the manuals say don't use this).

    What ever did 10w40 oil do to earn the wrath of neearly every car mfr???

    I used to use 20w50 in the 68 DVC but that was before the rebuild. I'm thinking 10w40 now. I'm certainly not going to use a 5w-anything in that car or the Fleetwood. On the other hand I don't want to have to stock 4 different oil weights in the garage - 2 coolant types is bad enough!

    Someone mentioned GM engine oil supplement having the zinc additive that we need. That stuff is like molasses and should help with thickening up the oil for the old 95 Fleetwood and 68 DVC.

    Does STP oil treatment have the same additives?? Either would be fine if they are both similar, but STP is available everywhere whereas the GM stuff is only available from dealers and maybe 1 shop in Tampa.

    damn friggin CAFE BS

  3. #18
    BluEyes's Avatar
    BluEyes is offline Cadillac Owners Enthusiast
    Automobile(s): 1970 Sedan deVille hardtop
    Join Date
    Feb 2005
    Posts
    595

    Re: Grade of oil

    I tend to use Rotella 5w40 synthetic. It's good for top-line diesels so it has all the good additives that the flat lifters want.

    If at all possible, you should go for a 5w-- or 10w-- oil. The first number is cold weight so a lower number means better cold flow for faster lubrication on a cold start especially if you drive the Cad during cold weather.

    The reason 10w40 is not reccomended on newer cars is that the engines are designed differently. Bearing clearances and design are different than they used to be and the bearings are designed to work with a 5w30 oil to take advantage of the reduced friction. Put 10w40 in there and the oil no longer flows through the system properly and will not lubricate the engine correctly.

    As for using straight weight oil, leave that ancient lube for the guys with flathead Fords and oil bath aircleaners! That 30 weight oil is going to be like sludge on a cold start and be murder on the bearings. My '70 FSM states SAE 30 and 20w40 oils only to be used at temperatures above 90*F, so summer in Arizona kinda weather... If you are truly hooked on single weight, the manual lists 20W oil for weather 32*F and above, 10W for 0-32F and 5W for weather below 0F (brrr).

  4. #19
    CaddySeville is offline Cadillac Owners Member
    Automobile(s): 81 Cadillac Seville
    Join Date
    Dec 2006
    Location
    Wausau WI
    Posts
    15

    Re: Grade of oil

    i use 10w-40 in my 368, last winter the temps got below 20F and my car started just fine.
    i was thinking of running quaker state high mileage 10w-30, would this benefit my engine or would it be just like running 10w-30 or 10w-40??

  5. #20
    BluEyes's Avatar
    BluEyes is offline Cadillac Owners Enthusiast
    Automobile(s): 1970 Sedan deVille hardtop
    Join Date
    Feb 2005
    Posts
    595

    Re: Grade of oil

    I don't thnk you'll have problems with the engine starting regardless of what weight oil you are running, the problem is running heavier oils in winter and the engine will be started but the oil hasn't made it to all the bearings yet

    10w40 will flow just as well when cold as any other 10w-- oil. That's how multigrade oils work, the first number is what weight is behaves like as 32*F and the second number is what weight it behaves like at 212*F. That's why synthetics are so great, you can get oils like 5w40 that flow great when cold, but keep their viscosity up as the temperature rises.

    The high mileage oils typically contain additives that will swell the seals on your engine to stop leaks. If your engine is not leaking, or not leaking enough to bother you, then do NOT use these oils. Once the seal has been swelled up by the additives, you are pretty much 'hooked' on the oil because if you take those additives away then the seal will sometimes shrink back and then you will have a nasty leak.
    If you want to change the oil from just being good ol' dino juice, then go synthetic. Synthetics in general hold up much better to high heat and extreme cold than conventional oils so your engine is better protected.

  6. #21
    cadillacmike68's Avatar
    cadillacmike68 is offline Cadillac Owners Enthusiast
    Automobile(s): 68 DVC, 96 FLTWD Brg, 09 STS N* Platinum, 11 CTS Premium
    Join Date
    Jan 2005
    Location
    Heading back to the sandbox!?!
    Age
    52
    Posts
    986

    Re: Grade of oil

    The 1995 Fleetwood manual says if its below 0F, use 5W-30. If it does not go below 0F, 10W-30 can be used. If it is always warmer than 40F, straight 30 can be used, but it has to be detergent (API SG or whatever) no non-detergent oild, or you can kiss your block goodbye.

    This is right from the manual. (not the part about kissing your block goodbye though)



    Since its' always warmer than 30F here, and 40F or above 10 months out of the year, I might go to a higher weight...

    Back in Mass, about 25 years ago, my brother put 50wt motorcycle oil in his 1970 Fleetwood 75 sedan. and then wondered why it wouldn't start in December

  7. #22
    limousine rider's Avatar
    limousine rider is offline Cadillac Owners Member
    Automobile(s): 1971 fleetwood, series 75<----Antique Land Yatch
    Join Date
    Jun 2004
    Location
    British Columbia, Canada
    Posts
    66

    Smile Re: Grade of oil

    Quote Originally Posted by cadillacmike68 View Post
    The 1995 Fleetwood manual says if its below 0F, use 5W-30. If it does not go below 0F, 10W-30 can be used. If it is always warmer than 40F, straight 30 can be used, but it has to be detergent (API SG or whatever) no non-detergent oild, or you can kiss your block goodbye.

    This is right from the manual. (not the part about kissing your block goodbye though)



    Since its' always warmer than 30F here, and 40F or above 10 months out of the year, I might go to a higher weight...

    Back in Mass, about 25 years ago, my brother put 50wt motorcycle oil in his 1970 Fleetwood 75 sedan. and then wondered why it wouldn't start in December

    As of now im running 10w-30 in all my cars but im starting to think i might want to go with a thicker grade now that the warmer weather is starting up. Maybe 20w-40 or is this to thick for a v8 ? One of my friends swears by it, all i want is the best oil presure and lubractor for my motor! what do you think about 20w-40 or is there an oil close to this grade but more available? Or is it to thick for the bearings to get lubed? what do you think about this?

  8. #23
    cadillacmike68's Avatar
    cadillacmike68 is offline Cadillac Owners Enthusiast
    Automobile(s): 68 DVC, 96 FLTWD Brg, 09 STS N* Platinum, 11 CTS Premium
    Join Date
    Jan 2005
    Location
    Heading back to the sandbox!?!
    Age
    52
    Posts
    986

    Re: Grade of oil

    I ran 20w-50 in my 1968 for 7 years with no problems. Your manual will probably state 10W-40

    My 1970 manual states that 10W-40 or 20W-40 can be used from 20F and warmer. or straight 30 if its above 60F.


    10W-30 is also ok for 0 - 100F...

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting