Requiem for the Cadillac Northstar

We may be seeing the last models with the Cadillac Northstar V8 engine.  Rumors are that the new Cadillac XTS, which will replace the DTS and STS, will not feature the Northstar.  With the retirement of the 1st generation SRX, and the XLR, no remaining models offer this powerplant, and the Northstar may go into retirement as well.  Let’s look in depth at this important power plant.

320 hp LH2 Rear-wheel Drive Variant

The Northstar V-8 was the basis for a technological renaissance at Cadillac, lending its name to an entire automotive system that includes the most advanced traction-enhancement, suspension and anti-skid electronics in the world when it was launched in the 1993 Cadillac Allante. The 90-degree Northstar was the first all-American dual-overhead cam aluminum V8 engine. Sixteen patents protected its advanced technologies; seven more have been granted since. In 1994, the original Northstar (RPO L37) was joined by a second version (LD8). Different camshafts and cam lobe profiles provided different power curves and very different driving characteristics. The L37 is more responsive, higher revving, with more peak horsepower and a higher redline (6500 rpm vs. 6000 rpm). The LD8 puts more emphasis on quick launch and part-throttle response, with greater peak torque. The L37 and LD8 are used in front-drive applications; the LH2 is the rear- and all-wheel-drive variant.

The Northstar was on the Ward’s 10 Best Engines list for 1995, 1996, and 1997.

Since the engine’s introduction, GM has steadily improved this premium V-8 and continued to push its technological envelope. In 2004, GM’s 4.6-liter Northstar V-8 made the transformation to be used in FWD and RWD/AWD applications. FWD applications benefited from a new, stronger forged steel crankshaft, a more powerful engine management computer, and several other key refinements that improved performance.

Also in 2004, the Northstar family of engines benefited from a host of new technologies and engineering features. For example, the LH2 Northstar debuted in the 2004 Cadillac XLR and SRX models, and in 2005 became optional in the 2005 Cadillac STS. Normally, a myriad of changes are required to adapt an existing engine to a new vehicle. In the case of the STS, only a different battery cable was required to enable the LH2 to bolt into an STS.

In the transition from FWD to RWD/AWD applications, the Northstar went from being transversely mounted to longitudinally mounted. Changes were major, and included the LH2 gaining variable valve timing (VVT), electronic throttle control (ETC), a boost in compression, a stronger engine block, a more powerful engine controller, polymer-coated pistons, high-performance exhaust valves, and a host of other technical enhancements. In total, the LH2 gained a five-percent power advantage over the FWD L37 Northstar.

The Most Powerful Production Northstar

The ultimate Northstar variant arrived in 2006 with the STS-V and the XLR-V performance cars.  This 4.4L Supercharged, Intercooled Northstar made 443 hp in the XLR-V, and 469 hp in the STS-V.

Supercharged Northstar

From its introduction as a 270hp engine to its final bow in 320 hp VVT Rear-wheel drive form, to Supercharged, intercooled, 4.4L 469 hp form in the STS-V from 2006-2009, the Northstar has delivered driving excitement.


  • Early Northstar engines had some gasket and seal issues. This was solved by 1995.
  • The Northstar has a reputation, deserved or not, for headgasket issues after 100K miles.  Magnifying this issue is that repair of head gasket problems requires removal of the powertrain due to packaging, and so requires a very expensive fix.  Several changes were made to the Northstar design over the 17 years of production, notably in 2000 and in 2004 that addressed this issue.
  • Lack of power updates:  the current 4.6L V8 in the Deville at 275hp has LESS power than the smaller 3.6L DI VVT V6 in the CTS.  That engine makes 304 hp.
  • Missing Ultra:  The Ultra V8 was the planned engine in development to replace the Northstar.  It would have been a V8 variant of the high-feature 3.6L engine, and so should have delivered over 385 hp.

Other Applications:

  • The Northstar has a good following among hot rodders especially for use in sand buggies (dune racers).
  • The least powerful Northstar was probably the 4L variant used in the Oldsmobile Aurora, which made 250 hp.  There also was a V6 variant based on this engine called the LX5  premium V6, that made 215 hp.
  • The Shelby Series 1 automobile used the 4L Northstar from the Aurora as its base engine, but also offered a supercharger as an option.

Conclusion: The Northstar was a very important engine for Cadillac.   Unfortunately, without technology updates to raise its effective output level, it has been surpassed by the performance of other Cadillac engines.  The expensive, hand-built LC3 Supercharged Variant solved the performance issues, but was a boutique solution and not the main production powerplant upgrade needed.

Cadillac Northstar Headgasket Repair

Cadillac Northstar Engine LD8

Cadillac Northstar Engine LD8

The Cadillac Northstar DOHC V8 engine is a terrific powerplant and has been in continuous production now for 17 years.  As with any mechanical system, eventually it will need maintenance or repair.   If the headgasket blows, or the head bolts pull, then the powertrain has to be removed from the vehicle, and the heads removed so that the gasket can be replaced.    The ‘shop manual’ repair for pulled threads in the block is to use TimeSerts to repair the holes.  A Timesert is a special type of threaded insert, and they have a manufacturer’s kit specifically for GM engines. I recommend anytime the heads come off a Northstar engine you go ahead and Timesert every bolt hole.  Northstar Performance of Langton, Ontario, Canada has developed a new repair system for the Northstar engine.

The Northstar Performance process?

  • The engine is removed from your car, thoroughly cleaned and inspected.
  • The cylinder block is machined to accept new custom cylinder head studs, designed by renowned Northstar enthusiast/technician Jake Wiebe, and exclusive to our shop.
  • Your engine is re-assembled with all new Fel-Pro seals and then re-installed.
  • Your engine is finally re-installed in your car with fresh oil, filter, and coolant.

What are these engine studs?

One piece CNC machined and heat treated studs completely eliminate the need for any type of threaded insert- the repair is the stud itself. There is a full 2 inches of thread gripping in the block- the most of any Northstar repair kit- and best of all it’s a one piece repair.

This message thread on the forum is a user review / report of the process:

If you can’t get your Cadillac to their shop in Ontario, Northstar Performance has a growing list of member shops throughout the USA and Canada who can install the Northstar Performance system for your Northstar engine.  Their webtool was not responding properly as I was writing this, but email or call them for a shop near you.

Northstar Performance also offers complete Northstar engines:

We offer the best remanufactured Northstar engines that money can buy. Our rebuilt Northstar engines are hand assembled to GM factory specifications, with a few improvements that would normally not be possible with mass production. Of course, all of the engines we sell are studded using our SureGrip studs so you’ll never have to worry about pulled head bolts again. Our 6 stage remanufacturing line involves disassembly and inspection, cleaning, machining, final clean, assembly, and testing. As of December 1st 2009, all engines will be run on a test stand at various RPMs before we ship, in addition to our normal compression and oil pressure testing phase.

How can I be sure I have a blown head gasket or pulled head bolts?

I know, don’t ask a barber to tell you if you need a haircut, but Northstar Performance also has a good diagnostic list to tell if you  have a blown headgasket.

What about cost?

  • A new engine installed by a Cadillac dealer can cost as much as US$10,000
  • The TimeSert kit costs US$450, plus you then need to remove, apply the Timeserts, replace the gasket, and apply to your engine.
  • A do-it-yourself kit from Northstar Performance costs US$550 with ground shipping, or US$649 with overnight shipping.  Plus you then need to remove your engine, apply the studs, replace the gasket with the one included in the NSP kit, and apply to your engine.
  • For CDN$2,200 Northstar Performance offers a drive-in, drive-out package.   For a single fee they will remove your Northstar, repair it, and replace it in your vehicle.

Contact information for Northstar Performance:

Northstar Performance graphic


Phone: 519-875-2970

Mailing & Physical Address:

Northstar Performance
2491 West Quarterline Road
RR4 Langton, Ontario N0E 1G0

Northstar Performance also has a subforum on

Cadillac is defined by Performance and Luxury, not by Cylinder Count

The Press has been agonizing over the idea that a new future Cadillac might have a 4-cylinder engine.  I addressed this a while back.  However, had an editorial on the subject today, (subscription required), bemoaning the idea that a REAL Cadillac cannot have a 4-cylinder engine and that it would be the Cimarron all over again.  All the bad things I mentioned in the previous article.

Let’s look at the facts.  Here are the performance output graphs for two powerplants:

Engine Dyno Saturn Sky Redline 2L Turbo 4

Engine Dyno Saturn Sky 2L Turbo 4

Engine dyno Cadillac DTS Northstar V8

Engine dyno Cadillac DTS Northstar V8

What do these show? That for a Driver, the GM Powertrain’s I4 Turbo will perform identically to the Northstar V8.

As one of my GM Engineer friends said, horsepower sells but you drive torque. Why do we WANT V8 or V12 or V16 engines? Because they give terrific torque at very low RPM very smoothly. So, especially in a large Luxury Cadillac, high torque at a low RPM means that the vehicle moves out smartly as soon as you engage the accelerator. So what is the problem with small displacement 4-cylinders? They tend not to make as much torque, and they make power higher in their RPM band. They use gearing to take advantage of the higher RPM power. But that means the power is not RIGHT THERE when I put my foot down.

How can we mitigate that? By using direct injection, high compression, and turbocharging as done with the I4 turbo. Now it puts out torque and horsepower similar to our current V8, for identical performance with better fuel economy at idle and off-power. We already have it available, in production. A new powertrain control module tune available now raises output to 280-290 hp for this engine, so it actually will be somewhat stronger than the Northstar V8 in the current DTS.

But what we WANT is that performance. It does not matter if it comes from an engine with 8 cylinders, or 6 (like my CTS) or 4 like a 1915 Cadillac or even 1 like the first Cadillacs. It matters that the engine is a precision built powerplant that provides smooth power delivery RIGHT NOW when I want to go. THAT is the definition of Cadillac. It is a premium high-precision vehicle that focuses on performance and luxury.

Bring me the new latest technology and stop worrying about change. Make a terrific Cadillac with luxury and performance and people won’t care how many cylinders it has.