Oil and Filter Question?

[mavric240]

I have an 1998 Cadillac Deville 4.6L N* 45,412 (Original miles). I am the second owner, and it has been well looked after.

My question is this...
Being a flat tappet motor with 300HP do I need to add any Zinc to my oil since it was originally designed for the SH specification?

I've been told that the SN oil specification does not have the needed additives for the protection of the flat tappet designed engines such as the N*. Everything I've read states that the N* needs the higher Zinc content due to the flat tappet higher horsepower design. If I should be adding ZDDP what would you recommend I use and how much should would I use? Speaking with another N* owner of the same year as mine told me he uses Shell Rotella 10w30. (I know its not a race car nor do I treat it as such) The car has only had Valvoline 10w30 with the exception of the oil from the factory and with the exception of the factory filter has had only Wix oil filters. The car has only had 6 oil changes in its life. Just looking to keep it as pristine on the inside as it is on the outside. Your input and comments are appreciated and welcomed.

 

[gregk24]

M1 HM has a fair amount of zinc, so does QS Defy. Both are HM oils but should suit your needs.

 

[ThirdeYe]

I would think that would be a great candidate for a higher mileage oil such as Mobil 1 HM, which is still SL rated due to the higher zinc levels it contains. At that age, some of the seals may benefit from the seal conditioners as well.

 

[aquariuscsm]

My car was originally specd for SH oil as well. I wonder what SH oils looked like back then? In 1996 I had my 87 Olds Trofeo. I always used GTX in it. Back then I didn't even know what SH meant.

 

[901Memphis]

I would use Mobil 1 High Mileage 5w30. You will want the 5 winter ratings for Ohio winter starts. That being said any good API SL, SM, SN oil should have sufficient anti wear additives for the flat tappet unless extra spring pressure was added.


Even Mobil 1 AFE 0w30 would be a good choice. Maybe even Caterham blend it Mobil 1 0W40 European Formula plus TGMO 0w20.

 

[NHGUY]

Cant believe that such an "advanced" engine as the North Star would use flat lifters and not roller.Just like 1982 when GM used a pushrod 4 for the J cars when everybody else had OHC engines the previous year (2.2 Chrysler/1.6 Ford)

 

[bigt61]

It's an overhead cam engine - no lifters. Very similar to what's in my 99 Aurora (4L version). I'd use any high quality 5W-30 synthetic.

Engine cutaway:
http://s.mlkshk.com/r/79LY

 

[Oil Changer]

Not to sound like a fanboy, but these older, well-maintained vehicles are perfect candidates for Mobil 1's ESP oils. If it were mine, I'd use M1 0W-40.

 

[volk06]

Originally Posted By: Oil Changer
Not to sound like a fanboy, but these older, well-maintained vehicles are perfect candidates for Mobil 1's ESP oils. If it were mine, I'd use M1 0W-40.


It needs some valvoline instead.

 

[berniedd]

A good HDEO like the aforementioned Shell Rotella 10w30 or Delo would fill the bill. Sure, they are for diesel engines, but you shouldn't have any problems using either.

 

[mavric240]

great information I will check out those oils, M1 HM sounds perfect.

 

[riggaz]

I wouldn't add zddp that's for sure, you'll most like just upset the additive package which will lower it's performance and negate any gain made with the extra zddp. Are there no API SJ or SL available? They will definitely be backward compatible with SH.

 

[Red91]

Any SN rated conventional is more than adequate for this application. There is no need for "high zinc". I bought into that for awhile, glad I got away from it. If it were mine, I'd run Quaker State conventional 5W-30 or 10W-30 and a WIX filter, 4K-5K OCI. If you have to have higher zddp, Quaker State Defy is a great oil as well.

 

[bubbatime]

I'd run Maxlife 5W30 or Defy 5W30 in it if I owned it...

 

[Greasymechtech]

Use any current spec full synthetic PCMO.

HM oils are an option. Thicker(Euro oil) is also.

I was engineered for a cave and prefer the winter house and summer condo. Zinc is overrated.

I've seen plenty of white sludge in E10 gas powered northern cool climate vehicles. Current spec PCMO's deal with white sludge. No ethanol in diesel fuel so i don't recommend HDEO's ability to deal with corngas.

 

[SilverC6]

Originally Posted By: volk06
Originally Posted By: Oil Changer
Not to sound like a fanboy, but these older, well-maintained vehicles are perfect candidates for Mobil 1's ESP oils. If it were mine, I'd use M1 0W-40.


It needs some valvoline instead.



Only after you run out of Pennzoil....

 

[SilverC6]

Originally Posted By: Greasymechtech

I was engineered for a cave and prefer the winter house and summer condo.


+1, good stuff here...