2001 BUICK PARK AVENUE

Typical onset: 60,000-120,000 mi

Symptoms: Coolant loss with no visible external leaks, White residue or 'milkshake' in oil cap area, Rough idle when cold, smooths out when warm, Coolant smell from exhaust, possible misfire codes

Fix: Replace lower intake manifold gaskets (use Fel-Pro 1200 or better, NOT Dex-Cool compatible OEM paper gaskets). Must remove upper plenum, fuel rails, ignition assembly. Strongly recommend doing valve cover gaskets, spark plugs, and coolant flush simultaneously. 6-8 hours labor for competent tech.

Estimated cost: $800-1,400

Typical onset: 80,000-150,000 mi

Symptoms: Pink or strawberry milkshake appearance in transmission fluid, Transmission slipping, delayed engagement, or complete failure, Coolant level dropping, transmission fluid level rising, Radiator leaking from plastic end tanks at cooler line connections

Fix: The radiator's integral transmission cooler develops pinhole leaks allowing coolant into ATF, destroying the 4T65-E transmission. Requires radiator replacement with external auxiliary cooler installation, complete transmission fluid flush (often too late), or full transmission rebuild/replacement if contamination occurred. Prevention: replace radiator proactively at 100k and add external cooler. Trans rebuild: 12-16 hours.

Estimated cost: $2,500-4,200

Typical onset: 90,000-140,000 mi

Symptoms: Whining or grinding noise from front of engine that increases with RPM, Supercharger oil leaking from front seal, Loss of boost pressure, reduced performance, Check engine light with fuel trim codes

Fix: The Eaton M90 supercharger's input coupler and front bearing wear out. Requires removing supercharger, replacing coupler, front bearing, and seals. Many shops replace entire rebuilt supercharger unit ($800-1,200 part). 4-6 hours labor. Also inspect serpentine belt tensioner and idler pulleys during this job.

Estimated cost: $1,200-2,000

Typical onset: 70,000-130,000 mi

Symptoms: Clunking when shifting from Park to Drive or Reverse, Excessive engine movement visible when accelerating/braking, Vibration felt through steering wheel and floorboard at idle, Driveline shudder on acceleration

Fix: Hydraulic transmission mount collapses, causing powertrain to sag and shift violently. Right engine mount also prone to failure. Replace both transmission and right engine mounts as a pair. 2-3 hours labor total. Inspect front lower cradle for cracks while underneath.

Estimated cost: $350-600

Typical onset: Not mileage-specific, age-related

Symptoms: Window drops into door, won't stay up, Grinding or clicking noise when operating window switch, Window moves slowly or unevenly, Window stuck in down position

Fix: Plastic regulator clips and gears break, especially driver's door. Requires door panel removal and regulator replacement (comes as complete assembly with motor). 1.5-2 hours per door. Front windows fail more than rears.

Estimated cost: $250-400

Typical onset: 80,000-140,000 mi

Symptoms: Clunking or popping noise over bumps, especially when turning, Steering feels notchy or catches when turning from center, Rattling from front suspension on rough roads, Uneven tire wear on front tires

Fix: Upper strut mount bearings wear out, causing noise and poor steering feel. Replace strut mount assemblies; recommend doing both sides with struts if originals (struts typically need replacement by 100k). 3-4 hours for mount-only replacement, 4-5 hours if doing complete strut assemblies with alignment.

Estimated cost: $400-800