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