View Full Version : "break in" period for new Northstar engine

11-07-07, 01:38 PM
Having a brand spankin new northstar put into my 2001 ETC.(dealer) Long block complete motor. Is there anything I should know about the break in period when I get my baby back? Hard accelerating, speed limits, etc. Any recommendations on how to drive it after the install and for how long (miles wise) until I dont have to worry about it? should I look at replacing anything else?

11-07-07, 02:01 PM
For the first 500 miles try not to run at any one rpm for extended periods. Don't run HARD, but don't baby it, either. Keep an eye on oil and coolant. It would be normal to add a small bit of coolant after things settle down in the first 250 miles. Perfectly OK to run posted limits, but as before, vary your speed a bit. Also perfectly OK to gradually work up to redline under light loads. DO NOT race it unloaded and in P or N. The absolute best thing would be to use the first 150 miles to make sure everything was mechanically/electrically OK, then take a freeway/side road trip to outside of LA and back.

From 500-1,000 miles, work the engine more, doing several WOT sequences after 750.

Not sure what the dealer/GM will say about oil/filter, but I would change to your favorite top grade oil and a WIX 51522 filter at 2,500. 5W-30 is recommended for your engine. Resist all temptation to dump snake oil enhancers into the engine.


11-07-07, 02:16 PM
For the first 500 miles try not to run at any one rpm for extended periods.... Resist all temptation to dump snake oil enhancers into the engine....

End of lesson.

11-07-07, 07:25 PM
With my new engine in my Seville STS, I had not gone further 4000 RPM , no hard launches a well . After hittin' 1500 miles, I had the oil changed as well

11-07-07, 08:55 PM
GM performance parts recommends driving it hard, and varying the RPM. The first few hours of running are critical to seat the rings properly. I'll see if I can find it

11-07-07, 09:11 PM
The engine should be driven at varying loads and conditions for the first 30 miles or one hour without wide open throttle (WOT) or sustained high RPM accelerations.

Run five or six medium throttle (50%) accelerations to about 5000 RPM and 55MPH (if application is a vehicle), and back to idle (0% throttle) in gear.

Run two or three hard throttle (WOT 100%) accelerations to about 5000 RPM and 55 MPH (if application is a vehicle), and back to idle (0% throttle) in gear.

Change the oil and filter. Inspect the oil and the oil filter for any foreign particles to ensure that the engine is functioning properly.

Drive the next 500 miles under normal conditions or 12 to 15 engine hours. Do not run the engine at its maximum rated engine speed. Also, do not expose the engine to extended periods of high load.

Change the oil and filter. Again, inspect the oil and oil filter
for any foreign particles to ensure that the engine is functioning properly.

There is also an SAE document on this: 2004-01-2917 (SP-1894)

11-07-07, 09:38 PM
I like this guys idea of a break in. To run it hard to properly seat the rings, etc.


I used his method to break my bike in. I beat the snot out of it, and have had no problems after 7,000 miles. I've also had lower than average oil usage.

11-07-07, 10:35 PM
Most cars are driven off the assembly line with a 30 sec idle. High performance cars are test driven hard while on the lot. That corvette with 20 miles probably has the hardest 20 miles of it's life on it.

11-08-07, 04:38 PM
Thanks guys for all the help. Lots of reading, I have lol. Man I cant wait to get my caddy back with that new northstar! Since Ive replaced everything else you could possibly think of, Ill be getting a "brand new" car back! yippee!

11-08-07, 04:56 PM
WooHoo !!! If there's any way to get to the tech who did the work, ask him straight out what oil is in the engine and when would HE change it. Read the fine print in the engine warranty BEFORE you head for the strip......:sneaky:

06-02-11, 03:45 PM
Approaching 500 on mine, going to do an oil change after work today, then after 1000 i was told to switch to synthetic.

06-02-11, 04:24 PM
Your engine uses flat tappet cam followers. You might want to look into the greater anti-scuff and anti-wear additive packages in the 10W-30 fleet/marine HD oils made by Chevron (DELO and variants), Pennzoil (LongLife) and Shell (Rotella). I prefer a WIX 51522 oil filter.

Yes, they're all rated for "diesel service" which simply means they have a greater soot detergency and anti-wear package than conventional "starburst" oils.

Why don't I use them ?? The 2000 and later Northstars use roller cam followers. The valvetrain does not need the extra protection, so I use 5W-30 Pennzoil Platinum synthetic and get over 4,500 miles/quart.

FWIW, after your first oil/filter change, cut the tapping plate off the oil filter case. Carefully remove the media pack, remove the ends and separate it from the center tube. Break the media into 10-pleat accordions. With a rag under, squeeze each accordion dry in a vise. Unfold each piece and inspect it for metal particles, disregarding the end at the case cut. Oil flows into the filter through the tapping plate holes and back to the engine through the center tube, so the "outside" of the media - the place where stuff will collect - is the side closest to the case. Silvery flakes are aluminum - piston skirts or bearing metal. Gray flakes are lead/antimony - bearing metal. Black/dark gray is iron - chain, cylinder bore, piston ring metal. You find much of anything other than some gasket flakes and a few dabs of silicone and you have troubles.