Jeep 4.0 Engine | Reliable Used Motors in NH

Introduction: The Legendary Jeep 4.0 Engine
The Jeep 4.0 engine (inline-six) is one of the most beloved powerplants in automotive history. From 1987–2006 it powered Cherokees, Wranglers, Grand Cherokees, and Comanches through decades of on-road miles and serious off-road abuse. Known for bulletproof reliability, excellent low-end torque, and simple design, the Jeep 4.0 inline-six routinely exceeds 250,000 miles—many run past 300,000.

When your 4.0 finally needs replacement, dealer quotes of $5,000–$8,000 and reman options at $3,000–$5,500 can exceed vehicle value. At 603 Auto Salvage, we stock quality used Jeep 4.0 engines—typically $1,200–$2,800—pulled from accident vehicles and low-mileage donor Jeeps. Browse our Shop or Contact us for a fast VIN match.

Understanding the Jeep 4.0 Inline-Six

The 4.0-liter inline-six evolved from AMC designs and became Jeep’s workhorse for two decades. Learn more about Jeep’s legendary inline engines on the Jeep AMC Inline-Six Wikipedia page.

• Displacement: 4.0 L (242 ci)
• Configuration: Inline 6-cyl; cast-iron block; cast-iron (early) or aluminum (later) head
• Bore × Stroke: 3.88″ × 3.41″
• Output: 173–190 hp; 220–235 lb-ft
• Compression: 8.8:1 (early) to 9.2:1 (later)
• Fuel system: Multi-port injection

Key features: Seven main bearings, hydraulic roller lifters, simple pushrod valvetrain, excellent low-RPM torque, and renowned durability. For original specifications, see Jeep’s official website.

Factory applications: 1987–2001 Cherokee (XJ); 1987–1992 Comanche; 1991–2006 Wrangler (YJ/TJ); 1993–1998 Grand Cherokee (ZJ); 1999–2004 Grand Cherokee (WJ select models).

Jeep 4.0 Engine Pricing: Real-World Comparisons

Typical 603 Auto Salvage Pricing (Jeep 4.0 I6)

• High mileage (180k–250k): $1,200–$1,600 (std) / $1,600–$2,000 (with accessories)
• Medium mileage (120k–180k): $2,000–$2,400 (std) / $2,400–$2,800 (with accessories)
• Low mileage (<120k): $2,800–$3,400 (std) / $3,400–$4,000 (with accessories)

Common Jeep 4.0 Inline-Six Issues & Fixes

Before you buy, review the most common problems Jeep 4.0 owners face. The enthusiast forum JeepForum offers community insight on maintenance and rebuilds.

• 0331 head cracking (1999–2001): Cracks between cylinders 3–4; prefer 0630 or TUPY heads.
• Rear main seal leak: Common but fixable; labor-intensive repair ($800–$1,400).
• Timing chain wear: Rattle at cold start; chain replacement restores timing accuracy.
• Piston slap & oil use: Typical of high-mileage 4.0s; not immediately catastrophic.
• Overheating: Often caused by neglected cooling systems; see Car and Driver’s Jeep reliability data.

How to Evaluate a Used Jeep 4.0 Engine

Mileage, Head Casting & Source History

• Ask for odometer photos and title proof.
• Prefer 0630 or TUPY head castings for strength.
• Check why the donor vehicle was retired (rear-end vs. rollover).

Compression & Oil Condition

• Compression: 120–150 PSI with <10% variance.
• Clean oil and no sludge = good care history.

External Inspection & Completeness

• Check for leaks, broken mounts, and cracked manifolds.
• Confirm all sensors, injectors, and harnesses are included.

What’s Included with Our Jeep 4.0 Engines

• Complete long block with head, pan, and timing set
• Intake, exhaust, alternator, power steering pump, AC compressor (if equipped)
• Fuel rail, injectors, throttle body, distributor (pre-2000) or coil pack (2000+)
• Full wiring harness, verified mileage, compression data, and warranty documentation

Wrangler 4.0 vs. Cherokee 4.0: Fitment Notes

Need fitment help? Visit the official Jeep Wrangler page for model-specific specs or ask our team to confirm compatibility.

• Accessory layouts differ between Wrangler and Cherokee.
• TJ oil pans vary for ground clearance; swaps may need pan changes.
• Mounts and sensors vary by chassis and year—confirm before purchase.

Customer Results: Real-World Jeep 4.0 Engine Swaps

Mike P., Londonderry NH: “Found a 2000 4.0 with the better 0630 head for $2,400. Installed over a weekend—saved >$4k vs. reman.”

Sarah M., Portsmouth NH: “Complete 4.0 at 156k for $2,200; two years of daily driving, zero issues.”

Dan R., Manchester NH: “~15 engines from 603. They know 0331 vs. 0630/TUPY. Honest, fair pricing, top quality.”

FAQ: Buying a Jeep 4.0 Inline-Six

How much does a Jeep 4.0 engine cost?

Typically $1,200–$4,000 depending on condition; most units $2,000–$2,800.

0331 vs. 0630/TUPY—what’s better?

0331 heads (1999–2001) are prone to cracks; 0630 and TUPY are more durable. Reference details at JeepForum discussion.

Can I use a Cherokee 4.0 in a Wrangler?

Yes, with minor swaps (oil pan, mounts, sensors). We help verify compatibility.

Do you test engines?

Yes, compression-tested when possible with results documented before sale.

How to Buy a Jeep 4.0 Engine from 603 Auto Salvage

1. Identify needs: Year, model, and casting number.
2. Contact us: Send us a message or call 603-392-7313.
3. Review options: We’ll explain mileage, casting, condition, and warranty terms.
4. Inspect on-site: Visit in person—bring tools for deeper inspection.
5. Purchase: Pay via cash, credit, or debit.
6. Pickup or Delivery: Same-day pickup or local delivery available.

Why Choose 603 Auto Salvage for a 4.0 Jeep Motor

• Jeep-specific knowledge (Renix, Chrysler EFI, TUPY heads)
• Documented testing and inspection
• Transparent, fair pricing with full documentation
• Complete assemblies with sensors/harnesses
• Local pickup convenience and fast service

Conclusion: Your Next Jeep 4.0 Inline-Six Is Ready

The Jeep 4.0 engine earns its reputation for longevity and torque. Skip expensive dealer quotes—get a tested, warrantied engine from 603 Auto Salvage and keep your Jeep adventure-ready. Browse our Jeep inventory or check NHTSA Jeep safety data for your model. Call 603-392-7313 today.