Customer Returned This Cadillac Northstar L37 4.6L V8, How Many Things Can We Find Wrong?

This could have been a world-beater, but GM, as always, snatched defeat from the jaws of victory

You could put that Northstar back together & it'll run! Re-seal the case halves, drill out the head bolt holes & put the helicoils in, drill the broken bolt out of the camshaft, replace the water pump & tensioner, & that thing will run for another 100K miles! I've done plenty of them! BTW, NEVER, EVER, use slicone sealer to seal the case halves. Use anaerobic sealer. That's all we used at GM. I appreciate your videos.

I've done Northstars including head and main stud conversions, not for the faint hearted! Once fixed they're a great engine! P.S. I can do the starters in under 30 minutes easily. The junk inside the water passages is most likely due to those horrid GM coolant tablets that GM told you to put in the cooling system! Some dumb goon has done a bottom end reseal on that oil pan and used too much silicone.

Seeing the cylinder heads after they went through the hot-tank was very satisfying, please show more hot-tanked parts in the future.

I guess i am the only one here who had a pleasant experience with a Northstar. Put 215000 miles on it. Did plugs once. Water pump belt and tensioner and a blower fan. Ran like a scalded dog and got great mpg. This engine was neglected. However, there was no catastrophic failure. Rods and bearings were intact. No piston to head contact. No stretched chains. Pure lack of preventative maintenance. Change your oil often and flush that coolant. Really a miracle with all of the silicone gasket material in the oil pump pick up.

As advertised by Cadillac the Northstar V-8 could be driven for 50 miles with no coolant...in an emergency. This engine looks like the owner ran an independent test on that theory. Jury still out on if it passed or failed...

I have never clicked on a video so fast. I am currently planning on building a 700 hp N/A Northstar for my 2008 DTS. This helped.

The Northstar head bolt debacle was corrected for the 01 model year and newer. I got 255k out of my 01 SLS before sending it to the boneyard with a bad transmission. Still ran strong...

I’m not mechanically inclined, but I’m fascinated by your videos, they never get old. Great work

Eric, they make a special tool that looks like a giant socket to remove the water pump from the housing. It turns about a quarter turn and pulls straight out. It seats in the housing against a large o ring.

My dad had a '94 Seville with the 275HP version. I did all the maintenance on it in the 13 years and 100k miles he had it, and nothing went wrong other than the water pump shaft seal seep and A/C compressor leak. These loved to rev and were pretty impressive for having been designed in the late 80's. Even the 4T80E trans shifted well. Too bad it was FWD. I remember reading about these having a limp-home feature where you could drive for 50 miles with no coolant. If overheated, it would run on 4 cylinders, alternating between banks so that the shut-off cylinders could air-cool themselves IIRC. If it got into this mode, the PCM would afterwards say "oil change required" as that would have cooked the oil.

As a retired Cadillac tech I can tell you the Northstar engine is an awesome engine. Incredibly well designed engine originally a LOTUS design. Early pre 2000 blocks had issues with head bolt threads. The later 2000 and up GM changed the alloy used in the engine block and eliminated the head gasket issue.

also the silicone used to seal the crankcase is an extremely common repair on Northstars...they love to leak in that area. However, the previous tech likely put WAY TOO MUCH sealant on there.

First, the RTV issue. There was a special policy repair on the lower block union oil leak. Was probably done by some idiot at a dealership. The blocks and head gaskets were upgraded to address leakage and thread pulling. The cooling system corrosion was due to low coolant, which allowed air into the system. The water pump had been leaking for a very long time. Very common issue. A special socket is used to turn the water pump out of its locks. I've seen them locked down, almost always resulted in head gasket failure. I own one, only because I couldn't find a decent used Lesabre. Working on cars for 45 years killed me physically, got to where I could no longer get in and out of my Duramax. I hope my 08 DTS will make it for a little. Good video.

Oh YES! As a Northstar owner (LD8) I've waited so long for this teardown video! Can't wait to see how this Rubik's cube of an engine comes apart.

I am of the belief, those who returned the core melted the pulley and broke the bolt. Only then did they discover the seized water pump. Of course it got left in the rain, before, during or after it got installed. Only for it to have to come back out. A super sketchy repower, right from the start. Thanks again for your hard work. I, like many others here really appreciate your efforts

I do a couple of these starters a year, you CAN pull the intake without messing with the fuel rail. Swivel 10mm socket and work that bolt up as you lift the manifold up then run it down as you put it back down. It's a little awkward but it's faster and easier than pulling the rail and messing around with seized fuel injectors on a plastic rail.

This Northstar appears to be fully rebuildable and there's a head stud upgrade kit for it that includes retapping the block for larger diameter studs, bigger studs included. Probably worth doing.

I had a 99 DeVille and that sucker was actually pretty fast. To this day it is still my favorite car I've ever had. Very comfortable and quick. And I always liked the old digital dashes. I would have had it much longer but I totaled it when I hit the back of a box truck!

Fun Fact: The Northstar V8, the C4 ZR1's LT4, and the V8 in your Lotus Esprit were co-developed and share many similar features and characteristics.