1995 cadillac seville oil

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crazyoildude

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Ok guys i need a vote here a friend of mine takes his 1995 Cadillac Seville with the 4.6 northstar to my shop for service..
The engine calls for 10w30 and that is what i always use (10w30 high mileage Pennzoil)
He wants me to put 5w30 HM in there for the winter and asked me what i thought about it.. I told him what i thought and then said i would ask everyone on my favorite forum.. I also use either a/c delco or purolator filters for him this car is babied most of the time and he always lets it warm up at least 5 minutes in the winter, car has 175,000 miles and runs like new
 
either is fine. 10w30 is ok to at least 0F

if there is going to be starting below that 5w30 would be better.

there is very little difference in those oils.
 
Dont be afraid to drive a little more "spirited" once in awhile. Babying a Northstar can gunk up the rings ove the long term.

As for oil, I agree, keep using what you want to use. Its your car, after all, not your mechanic's car!!!

AC or Purolator filters, no problem there!!
 
like bobfather said, it seems the 'health' of a Northstar engine is directly attributal to how it's driven, and not the way most would think.

If this engine 'granny driven', the rings gunk up, stick in the bores, and the engine start consuming crazy oil. This engine NEEDS to be 'opened up hard' regularly to run right. If this isn't done, it doesn't really matter wehat oil you use - it will get consumed. If this is done, oil consumption will be less.

What is oil consumption like now?
 
When using 10w30 regular pennzoil it does not burn any oil at all although there is an oil leak, on the other hand with high mileage 10w30 it hardly leaks at all and does not ever need make up oil even on a long trip at between 50 and 80 mph its just the noise that bothers everyone again its not always present.. I think im going to get the high mileage oil out of there tomorrow and put in the regular 10w30 for the winter the hm seems really thick
 
The HM stuff is thick, but it still meets the 10W cranking values...I'd switch to the 5W-30 HM. Then you get the 'best of both worlds'.....
 
It is pretty thick i don't like using it in the cold winter months i might go to the yellow bottle for the winter.. What does everyone else do on here?
 
A cadillac powertrain engineer said the 10W-30 was recommended for the direct acting cams, as they are not roller on the 93-99 Northstars. However, he also stated that the earlier oils were not as good as current oils, so the 10W was recommended for possible higher temps (summer) and making sure the hydrodynamic film stayed thick enough on the cam lobes.
-However, with recent day quality 5W vs 10W oils, that issue isn't a problem. He said either is just fine, and long term testing showed no problem with either 5W or 10W. The best is to use 10W-30 when temps will consistantly be above 60'F, and use the 5W-30 for winter or when temps will be cold (usually lower than 60'F). The 5W-30 will help to get oil to the upper-end of the Northstar upon cold winter starting.

A friend used Castrol HM 10W-30 in a 95 Seville in MN. It rapped for a bit until the oil was circulated. If it gets cold, the 5W may be the best overall choice for that engine in winter and 10W in summer. Good luck!
 
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I am driving my 2nd N* caddy this one being a 1996. I have not had any major issues with either engine and perhaps I baby the thing too much as mentioned. They have a tendency to build up carbon in the quench zone of the chamber causing a rapping that goes away if you power on to a interstate WOT. These engines during the 96-99 era commonly had frequent ex. cam & valve bucket failures. This defect was over shadowed by the extremely high rate of head gasket failures. GM dropped the ball sending many thousands of defective engine block castings out the door. Castings were so porous the oil leaked right out pan, side of the block, same issue with the coolant. Head machined threads turned into powder, If you had no warranty $5500 to $7000 is the cost to repair. That is catastrophic. Cam bucket/followers were not up to par causing those failures. These failures all could occur any time after 40,000mi. If the exhaust cam is what failed feel lucky. It could be fixed for half the expense of a head gasket. I have used M1 10/30 for 450000mi. droped every 4000. I going to start using Mystic now due to it being $10 cheaper per change.
 
I did not know that the 4.6 Seville Northstar came in a Diesel form...I wondered about that as one of my neighbors Seville [99 I think] sounded just like diesel whenever I heard it pass..It also smoked a bit also....I thought it was just carbon building up as all she ever did was stop and go driving and no highway.
 
The Northstar gets a bad rap but its actually a pretty sweet engine. The heads are basically a modified version of the LT5 heads off the early 90's ZR1 corvette. It was a 5.7L DOHC 32V V8. The heads were designed by Lotus for GM. Although plagued with head gasket problems and a few other problems its a very strong engine that loves high rpms. It was Tested for 300 hours at redline multiple times. Its too bad GM put this motor is a bunch of grandpa and grandma cars and not a little RWD 2 door coupe or a manual transmission. The motor was designed to be run hard which is why when babied the rings gum up and the motor uses alot of oil. The procedure for that was to go on the highway in second car and floor it up to redline then come off the gas and let the rpms fall back down to about 2500 and repeat this 2 or 3 more times. I had a 93 STS with 195,000 on it when i get rid of it. It was still running strong, used very little oil and never had the headgaskets replaced. I paid 3 grand for this car and it was in mint condition, I basically drove this car like it was a rental everywhere i went. The car was a beast. The best oil for this motor up till 99 when the roller motor went into service ( and this was recommended by a GM engineer who designed the Northstar ) is Rotella 15W40. You can read all about this motor in the Technical section on the cadillac forums all you want.

www.cadillacforums.com
 
here in my engine shop we see our fair share of northstars with head bolts pulling out of the block but i have to say most of them have over 150,000 miles on the clock.. I happen to own a 95 myself has around 40,000 miles on it i purchased this car new... In my opinion there is nothing like a Cadillac..
 
under $3500.00 in my shop done correctly
We helped pioneer the rebuilding process using in some cases head bolts from a mb
 
I want to agree with DSteven using the 5w30 in the northstar of that era problem is most of those northstars leak oil mine had a slight leak from day one.. I would say everyone we see here for engines leak a little granted most have over 150,000 when we see them
 
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