Need suggestions for Northstar Motor

[mag176]

Hi all,
I just recieved a 2001 Cadillac Deville from an aging relative, sad when a man cant drive anymore. Anyways,he bought it with 40,000 on it,it just turned over to 70,000. Started the car and the low oil message appeared. He told me he had oil in the garage. He proudly has used Penzoil 30 HD.
No oil showed on the dipstick so I put it in and drove to the first oil change place I could find. Iffy Lube. I do all my own maintaince but I was 100 miles from home and wanted two change the oil now. The oil cap recommends 5-30 so it got castrol conv. motor oil put in.
Coming home I noticed a Iffy Lube sticker in the window and the car had an oil change less than a 1000 miles ago. Im thnking they only put in five quarts. Cap. is 8 quarts w/ filter.
Motor sounds perfect. Maybe an RX treatment and keep an eye on the oil.
Thanks in advance.
Mark

 

[sciphi]

Start romping on that thing for about 1000 miles or so to clean up the internals. Not to excess.

Change the oil again, and start your ARX treatment.

I did the same thing to a 99 Buick LeSabre I got from an elderly relative a year ago. The motor runs fine with 57k on the odometer.

 

[jldcol]

A few on here have said these motors can/do use oil, although there are different versions of them, so I do not know if one of these is yours. If now properly filled watch the oil level, as any good BITOGER would anyway. Dry dipstick I think even with that still about 5 qts. in sump, enough to keep motor safe.

 

[tig1]

Some Caddy's have had oil consumption problems. Google it and see what comes up.

 

[wgtoys]

I would do 3,000 mile OCIs with any good brand conventional oil and do three UOAs in a row to see how things are looking. There is really no way to know how the engine was maintained up until now. I'm not normally a 3k mile guy, but in this case I would go that way to gather some data.

Some Northstar owners have reported high (in modern terms) oil consumption in the 1 qt/1000 mile range.

Also, change out the coolant, transmission fluid and brake fluid. All are probably the originally installed stuff and they would be well served by freshening.

 

[artificialist]

Northstar engines do require 8 quarts of oil, so I could understand if some oil change places rip off customers by putting in only 5 or 6 quarts.

Many people have reported that carbon clings to the piston rings, and the way to get rid of them is to pull out the spark plugs, put some GM Top Engine Cleaner or Seafoam, and let the car sit overnight. After that, the engine must be cranked with plugs out to get rid of the solvent. Put the plugs back in, and drive the car hard.

And +1 on replacing the other fluids.

 

[calvin1]

Originally Posted By: sciphi
Start romping on that thing for about 1000 miles or so to clean up the internals. Not to excess.

Change the oil again, and start your ARX treatment.

I did the same thing to a 99 Buick LeSabre I got from an elderly relative a year ago. The motor runs fine with 57k on the odometer.


Amen to that! It's a 32v V8! If there ever was a car that wanted the old Italian tuneup, this is it. How many of these actually get driven beyond 5% of their capabilities?

 

[bobfather99]

Keep an eye on the coolant too. If it becomes acidic it can eat up your head/intake gaskets.

If it were me I would flush the coolant out, and use your preferred brand of new stuff. I would also use the GM coolant tabs, just to be safe. I would change every other fluid you have as well.

 

[Fordiesel69]

Originally Posted By: bobfather99
Keep an eye on the coolant too. If it becomes acidic it can eat up your head/intake gaskets.

If it were me I would flush the coolant out, and use your preferred brand of new stuff. I would also use the GM coolant tabs, just to be safe. I would change every other fluid you have as well.


x2. I prefer zerex G05 for a dexcool replacement.

On the northstars, my buddy recommends gm top engine cleaner in the cylinders with your old oil. Then change oil and run an arx treatment for recommended intervals. Good top quality synthetics will cut back in the carboning, and a few WOT runs per month will help keep it clean.

 

[mag176]

Thanks for all the ideas. I have had a number of people say Romp on it once in a while and it will keep the carbon out of the rings. Coolant change will be done this week with gm tablets put in. Still dont know whether to use dexcool or G05.
Thanks again, Marl

 

[tig1]

Originally Posted By: mag176

Thanks for all the ideas. I have had a number of people say Romp on it once in a while and it will keep the carbon out of the rings. Coolant change will be done this week with gm tablets put in. Still dont know whether to use dexcool or G05.
Thanks again, Marl




A good synthetic will keep carbon deposits from forming around the rings.

 

[mag176]

Maybe after a ARX treatment. Northstars sometimes leak at the half case which you have to suffer with or spend 1500. to fix, or so I have read.
Mark

 

[Chris142]

Hope you never have to put a starter or water pump in that pile.

 

[CBOYLE15]

I have had a few Northstars. These motors are designed to use some oil. Just add it when necessary. The lower half shaft design of tne motor's may or may not leak oil. If you are lucky it will not be a leaker. If it does leak and it bothers you you will have to make a decision to fix or get rid of it. You have to pull the powertrain out. It is a two day job at a good dealer with some new factory fixes that will last a while. The cost is about $3K. Drain and refill the coolant with 50 50 of Dexcool only with 3 crushed GM tabs on the Lower hose NOT the recovery tank. Northstars like to be run hard. Their are a few Caddy forums out their that you may want to read. My 1999 was a real leaker My 2001 has been good. I do not recommend Synthetic oil. My preference is GTX 5W30
Good Luck

 

[mag176]

Thanks CBOYLE15,
Coolant changed today, tabs went in hose. I found a couple of caddy forums you mentioned, good stuff there. Doesent drop oil on floor but I see a little oil mist and dirt on the bottom of the motor. Have to get it on ramps and check it out. If that was as bad as it was going to get ,I could live with it.
Engine sounds great when you jump on it and it runs like a stripped a$$ ape.
Thanks again, Mark

 

[CBOYLE15]

A couple more things.
Do not use ANY additive in the motor.
Use exactly 7.5 quarts with a filter. Do not just pour in 8 quarts.
Run it up in 2 gear to about 70 MPH and let off the gas as it slows down the Northstars like the sucking on deceleration that helps with the carbon. Do it 2 or 3 times in a row.
Enjoy your Ride!
Charlie

 

[lexus114]

Just curious,why don`t you recommend synthetic oil in this application?

 

[CBOYLE15]

My 1999 SLS never leaked a drop until I changed it over to Mobil 1. Just my experience. We recently took delivery of a 2008 STS with a 3.6 Direct injection. Mobil 1 is required.