What was supposed to be an advanced V8 engine to take on the Europeans and Japanese towards the end of the 80's ended up being an expensive to repair problem for a lot of people (including my cousin and his STS). Where did it go wrong?
GM started the development of what would be come the Northstar engine family back in 84 in anticipation of the coming onslaught of German and Japanese luxury sedans that would change the game at the end of the 80's. Its development coincided with some sophisticated stuff coming from Cadillac to combat the foreign brands such as the Allante, Eldarado and Seville. All these models were going to come with advanced features. The Northstar was supposed to be a centerpiece for some of these models.
When all was said and done the engine was originally 4.4 liters and was capable of pushing out 300 horses and featured some advanced designs and features that would ultimately prove to be a headache for many owners years later. From Wikipedia: GM specified cast-iron cylinder liners and the cast aluminum pistons included valve clearance. Northstar is an interference engine, the valves will strike the pistons if they lose timing. It has bronze piston pin bushings and free-floating piston pins. GM used cast aluminum cylinder heads featuring 4 valves per cylinder. The heads used dual overhead cams driven through the “maintenance-free” cam-drive chain case. The cams act directly on hydraulic lifters on the ends of the valves and are fed with a lubrication passage drilled through the cylinder head lengthwise. The intake valves are inclined at 25°, while the exhaust valves are canted to 7° with center-mounted platinum-tipped spark plugs. The cam covers are magnesium for light weight and sound damping.
The engine ended up being a cornerstone of Cadillac. It was introduced in the 93 Allante, which we all know came too late for the model and probably would have helped it had it been introduced with it in the first place.
The introduction of the Northstar on the Allante (and eventually made its way to the 93' Seville and Eldorado) also introduced what was called the Northstar System, which was a performance package. It came with:
- Heavy Duty 4 speed auto
- Road Sensing adaptive suspension
- 4 Wheel anitlock disc brakes
- Magnasteer variable power steering
Throughout its run the Northstar was a Cadillac only engine. Only until the mid 00's did GM give the engine to other models with it being used in the performance model Pontiac Bonneville GXP and in both the Buick Lucerne Super and the regular Lucerne V8.
Oldsmobile got a variant of the Northstar called the L47 internally. It was used in only the Aurora from 95-99 and them from 01-03 on the second gen. It was 4.0 liters and pushed out 250 horses which I always found a bit low, especially considering the same power could be had from supercharged 3800's from the same year.
Another Olds variant was the “Shortstar”V6 used in the Intrigue and base Aurora. Called the LX5 internally, it pushed out a measly 215 horses. It was never used in anything else and ceased to exist when Olds went to the great dealership in the sky.
The Northstar eventually grew to be a family of different engine variants. Along with the 2 Olds variants listed above, there was also:
- The origional L37 which was 4.4 liters and 290 horses. It only made 300 in certain performance high output models.
- The LD8, which was what the Northstar eventually became putting out 275 horses.
- The LH2, which was originally designed for fwd applications. It was modified for awd, specifically SRX, and was only ever used in the STS, SRX and XLR.
- The LC3, which was the superchaged version for the STS and XLR V’s. Both were identical, but put out differnt power numbers with weirdly the STS being more powerful.
Allegedly there was supposed to be a V12 Northstar for use in the Escalade back in 03', but sadly it never saw the light of day. An Ultra engine was also being developed to replace the Northstar, but it was canceled right before the BK. Rumor has it that the gorgeous Elmiraj concept from 2013 is powered by a variant of this Ultra engine.
So where did this sophisticated engine go wrong? Well from years of it being into production, problems are well known, widespread and easy to find out, and it mostly looks like quality problems. Combine that with how sophisticated GM designed the engine and they can prove to be costly, almost German like in their repair costs. Everything from head gaskets, which are to believed to be a problem on all the 4.6's, to crank sensors, 98-04 Seville’s vibrate 65-75 mph, motor mounts are a universally issue, the list goes on and on.
I always liked this engine and thought that if GM hadn’t had the quality problems this engine would probably still be around today. If the Japanese or Germans had done it it still would be. So where do you guys think it went wrong, either from experience or what you know?