Advice on Cadillac with 4.6 Northstar...

[GLISHO]

Hey everyone, I've searched and searched but haven't found a whole lot on what people prefer on Northstar-powered Caddy. I'm about to buy a 97 STS from my parents with about 160k on the clock. My dad uses Dino oil (whatever's cheapest, unfortunately. Usually Meier's brand oil) and I was hoping to switch to a higher-quality oil as SOON as I get the car so it'll hopefully last me a bit. I'm thinking Valvoline Maxlife as the car burns QUITE a bit of oil as it sits. Should I stick with Dino oil or switch to a Synthetic? I'm not really worried about "cost" as I work for an oil distributor and can get either oil for quite cheap Thanks for your insight!!

 

[HTSS_TR]

If you can get Maxlife Full Synthetic 5W30 from your work, it will be a good choice.

 

[RF Overlord]

GLISHO, I'm by no stretch of the imagination very knowledgeable about the Northstar, but I've heard that the older ones DO burn oil due to poor design or a manufacturing defect. Apparently it doesn't matter what oil you use. I think you'd just be wasting your money on synth as it won't help the consumption.

 

[crazyoildude]

fast reliable car, the northstars are sometimes prone to oil leaks and sometimes they have head gasket problems.. Those 4.6 northstars are expensive to fix...sometimes the head bolts pull out and an insert sometimes has to be installed although sometimes larger head bolts seem to work also..
Other than that it is a nice car we have a 4.6 here at the shop for an engine rebuild it is a 1996 seville and it has 222,000 miles on it... This guy changed the oil only once a year! Sludge city
I personally have one and love it
Don't use synthetic in that northstar it will leak!

 

[GLISHO]

Alright, Dino oil it is! Yeah I heard that the oil consumption was due to very soft piston rings in the earlier Northstar engines. I guess I'm just looking to minimize that problem haha. I was thinking of Lucas oil stabilizer but I read a lot of negative stuff about that recently so fuggetabout that.

 

[Hokiefyd]

I had a '97 SLS and an '01 STS. I'd use some 10W-30 MaxLife or other high mileage oil in the '97. It recommends 10W-30 oil and that's probably what I'd stick with. 5W-30 oil should be fine also. My '97 had a slow leak at the rear main seal, but the '01 was tight as a drum. Run the engine hard or the rings tend to get sticky. It's a good engine.

 

[artificialist]

Some Northstar engines were prone to oil burning because they were prone to having carbon deposits on the piston rings.

The solution is to pull out all spark plugs, put decarbonizing solvent in each cylinder, letting it sit overnight, crank the engine with plugs out, then put plugs back in.

When the Northstar works, it works well, however, when it breaks, it does so in an expensive way.

 

[ronrackley]

Love those Northstars, but it seems the older ones always used significant oil. My wife and I are going on our third and fourth Devilles with that engine. I ran my 2000 to almost 170,000 miles and we traded my wife's 2001 at close to 150,000 miles. Both were running like new when we let go of them earlier this year and I assume they will each last for many more miles.

The 2000 used about a quart every 2000 miles when I first got it with about 20,000 miles and was up to a quart about every 1500 miles at the end, running Mobil 1 10-30 or Pennzoil Platinum 10-30. I just kept adding oil and didn't worry about it.

The 2001 we got with about 100,000 miles and it always drank a lot of oil - like a quart every 700 miles when I changed it to Pennzoil Platinum synthetic 10-30 at first. I tried Pennzoil HM 10-30 for two OCIs and it maybe went up to a quart every 800 miles. Finally was getting about 1000 miles to a quart with Shell Rotella 15-40. That's what it drank the remainder of the time we owned it and we just lived with it. I carried a quart in the trunk on trips, if you know what I mean.

The oil usage with our 2000 and 2001 Devilles didn't seem to be related to anything else at all. Both ran great, got about the same gas mileage no matter what oil we had in them (25 - 26 MPG at 75 MPH on our flat Florida Interstate highways) and we weren't seeing drips on the driveway. There was no smoke or spark plug fouling. Where it was going was always a mystery to me.

The 2003 and 2005 Devilles we have now never have to have oil added during their 5000 mile OCIs. That is nice, but they don't drive any better than the old ones did.

I hope you find encouragement in my words.

 

[addyguy]

Originally Posted By: artificialist
Some Northstar engines were prone to oil burning because they were prone to having carbon deposits on the piston rings.

The solution is to pull out all spark plugs, put decarbonizing solvent in each cylinder, letting it sit overnight, crank the engine with plugs out, then put plugs back in.

When the Northstar works, it works well, however, when it breaks, it does so in an expensive way.


Another way to 'fix' this is a very hard Italian tune-up. Although put in a luxury car, these engines need to be run hard to work optimally.