Why Does Cadillac's Northstar Engine Get Such A Bad Rap?

The Cadillac Northstar V8 has, let's telephone it, a "negative reputation." And why is this? Some of you raised your hands for illustration an A+ student who sits astatine nan beforehand of nan people and shouted, "Head gaskets!" Very good, you get a golden star, but it is truthful overmuch much analyzable than that. The existent mobility is why caput gaskets thin to rustle connected early Northstar V8s. The biggest issue, and nan 1 that makes galore potential secondhand owners excessively frightened to ain one, is that nan good alloy threads of nan torque-to-yield caput bolts connected early engines would portion correct retired of nan aluminum block. 

Over time, galvanic corrosion would eat distant astatine nan threads, and erstwhile nan bolts were stripped, nan heads could propulsion distant from nan block. Coolant would past get into nan cylinders, and of course, compression would drop. Aside from caput bolt problems, early Northstars could besides create an lipid leak because nan rear main seal wears down faster than it should. As explained by 8020 Automotive, GM didn't property nan main seals into nan artifact from 1993 done 1999, but changed nan creation successful 2000 to forestall early leaks.

Speaking of '93 to '99 examples, excessive lipid depletion is communal acknowledgment to piston rings that build up c deposits, ruining their expertise to seal against nan cylinder wall. New rings fixed this problem successful 2000. Oh, and GM still wrestled conclusion from nan jaws of victory, because from 2000 to 2002, nan c conscionable built up wrong nan cylinders instead, starring to overheating. Also, valve screen gaskets tin leak and drip lipid onto nan motor mounts, alternator, A/C compressor, and exhaust manifolds, which are not perfect places to person lipid dripping.

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Trying to find a definitive reply connected erstwhile GM yet fixed nan caput bolt rumor is for illustration trying to find an nonsubjective reply astir who's nan alien astatine nan extremity of John Carpenter's "The Thing". At slightest we cognize why the Cadillac logo utilized to person ducks successful it. Northstar Performance's Swap/Interchange page timeline shows changes made to nan motor complete nan years, including longer caput bolts introduced successful 2000. However, according to a work bulletin per Wise Auto Tools (opens a PDF) in late MY2002, GM introduced fixes for nan stud issue, raising nan thread commencement tallness and nan artifact bolt spread extent by 7mm.

While it mightiness look this negates Northstar Performance's timeline, looking astatine that aforesaid bulletin, we spot that it recommends a circumstantial TimeSert kit for fixing 2000-2003 Northstar caput bolts, past shows a array pinch circumstantial bolt dimensions, implying nan bolts were nan aforesaid during that four-year period. According to some nan work bulletin and Northstar Performance's timeline, nan good M11x1.5 bolts were replaced successful 2004 pinch coarser M11x2.0 bolts, truthful it seems that was nan twelvemonth that GM sewage superior astir fixing nan Northstar's issues. But, spell to Repairpal, and spot that 2004 and 2005 Cadillac DeVilles person reports of caput bolt problems anyway. 

Then, spell to nan forums, arsenic good arsenic nan comments conception connected Motorweek's reappraisal of nan 2006 Cadillac STS-V, and group support referring to 2003 caput bolt revisions. It's imaginable group are conflating nan caput bolt rumor pinch nan acold commencement motor sound problem, which was, according to nan work bulletin, a information suffered by 2000-2003 Northstars.

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These days, Northstar Performance offers a kit to permanently repair nan caput studs successful your aged Northstar and, arsenic The Car Wizard explained, makes nan Northstar wholly reliable, though nan hole is costly and time-consuming. Can you ideate doing this hole connected a Mosler Cadillac Twinstar pinch 2 Northstars? Shudder. You could debar nan 4.6-liter Northstar issues wholly by getting 1 of nan 2 cool mill supercharged Northstar Caddies: The XLR-V aliases nan STS-V. Watch nan STS-V Motorweek review, moreover if for nary different logic than to perceive John Davis's cleanable voice, and you'll announcement that nan displacement has shrunk from 4.6 to 4.4 liters, yet horsepower ballooned to 469 hp, rivaling nan W211 Mercedes-AMG E55 (443 successful nan XLR-V). 

In summation to reducing nan bore and decreasing compression successful mentation for supercharging, nan artifact is sand-cast alternatively of die-cast, nan platform is semi-closed, nan h2o overgarment was improved for amended coolant flow, and nan caput gaskets were changed complete to coated multi-layer alloy to grip nan accrued pressure. The champion part? Owners study nan LC3 is stout pinch nary gasket issues, and STS-Vs are ridiculously cheap. Sure, nan XLR-V has erstwhile been referred to arsenic "the biggest disappointment successful car history," but yesterday's awkward creation is today's quirky and unique.

Unfortunately, by nan clip nan niche supercharged 4.4 type came retired — and nan gasket issues were besides mostly solved for nan N/A 4.6 — nan harm was done. Perhaps GM took excessively agelong to admit and reside nan problem, aliases possibly nan attraction shifted to nan LS arsenic nan capacity V8 of choice, acknowledgment to its durability and comparative simplicity, but nan Northstar was dormant by 2011.