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Cummins Water Pump 3.9L 5.9L 3903749 4B 6B

Cummins Water Pump 3.9L 5.9L 3903749 4B 6B

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$42.99
$42.99
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Direct replacement water pump for Cummins 4B (3.9L) and 6B (5.9L) diesel engines. Prevents engine overheating by circulating coolant through the cooling system. Essential component for reliable engine operation in Case IH tractors and industrial equipment.


Part Number:
• 3903749


Replaces OEM Part Numbers:
• 4429404, 3802004, 3913432• 3802358, 3802970, 3286277• 3920311, 3389145, 3960342• 4089700, 3960309


Fits Cummins Diesel Engines:
• 4B (4BT) 3.9L• 6B (6BT) 5.9L


Fits Case IH Tractor Models:
• MX100, MX135, MX150, MX170• 140, 1620, 1640, 1644, 1896• 2096, 2144, 2166, 2188, 2344• 5120, 5130, 5140, 5150• 5220, 5230, 5240, 5250


Application:
Designed for Cummins 4B and 6B diesel engines used in Case IH tractors, industrial equipment, and other applications. Ensures proper coolant circulation to prevent engine overheating and damage. Critical for reliable equipment performance.


Installation Note:

Replacement requires draining coolant, removing drive belt, disconnecting hoses, and removing/installing water pump. Professional installation recommended. Always use fresh coolant and follow Cummins specifications.


Ships fast from our USA warehouse with same-day processing on orders placed before 3 PM PST.

Not sure it fits? Call (818) 261-3896

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COMPATIBILITY

Fits These Cummins Engines & Case Tractors

✓ Cummins 4B 3.9L Diesel Engine
✓ Cummins 6B 5.9L Diesel Engine
✓ Case IH MX100 / MX135 / MX150 / MX170
✓ Case IH 140 / 1620 / 1640 / 1644 / 1896
✓ Case IH 2096 / 2144 / 2166 / 2188 / 2344
✓ Case IH 5120 / 5130 / 5140 / 5150
✓ Case IH 5220 / 5230 / 5240 / 5250
✓ Other 4B / 6B Powered Equipment

WHAT'S INCLUDED

Complete Water Pump Assembly

💧
Water Pump Assembly
✅
OEM Quality
🔧
Cummins 4B / 6B
📐
Part #3903749
🚜
Case IH Compatible
🚚
Same-Day Shipping

WHEN TO REPLACE

Warning Signs of Pump Failure

Replace your water pump immediately if you notice:

⚠️ Coolant leaking from pump
⚠️ Engine overheating
⚠️ Bearing noise or grinding
⚠️ Temperature gauge running high
⚠️ Visible corrosion on pump
⚠️ Steam from engine compartment

CUSTOMER REVIEWS

Trusted by Tractor Owners Nationwide

★★★★★ 4.6 out of 5 stars (927 reviews)
★★★★★
Perfect Fit
VERIFIED REVIEW

"Exact replacement for my Ford 4600. Installed in 20 minutes and tractor fired right up. Quality part at a great price. Will order from Arko again."

Mike T. • Verified Buyer • March 2026
★★★★★
Fast Shipping & Great Support
VERIFIED REVIEW

"Ordered Monday morning, received Wednesday. Called with a fitment question and spoke to someone who actually knew tractors. Part works perfectly on my Kubota."

James R. • Verified Buyer • March 2026
★★★★★
Better Than OEM
VERIFIED REVIEW

"This gasket kit saved me hundreds compared to dealer pricing. Quality is excellent, everything fit perfectly. No leaks after 50+ hours of operation."

David L. • Verified Buyer • February 2026

FAQ

Common Questions

Which Cummins engines does this water pump fit?

This water pump fits Cummins 4B (3.9L) and 6B (5.9L) diesel engines used in Case IH tractors and other industrial equipment. Compatible with Case IH MX100, MX135, MX150, MX170 and many other models. Part number 3903749. Call (818) 261-3896 for fitment confirmation.

What OEM part numbers does this replace?

This water pump replaces multiple Cummins OEM part numbers including: 3903749, 4429404, 3802004, 3913432, 3802358, 3802970, 3286277, 3920311, 3389145, 3960342, 4089700, 3960309. These are all interchangeable Cummins part numbers.

Does this fit both 4BT and 6BT Cummins engines?

Yes! This water pump is compatible with both Cummins 4B (4BT - 3.9L) and 6B (6BT - 5.9L) diesel engines. The cooling system design is the same for both engine families.

What's your return policy

We offer free returns within 30 days if the part doesn't fit or you're not satisfied. Parts must be unused and in original packaging.

Do you offer technical support?

Yes. Call (818) 261-3896 and we'll help you confirm fitment, answer installation questions, or troubleshoot issues.

How long does shipping take?

Orders ship same-day if placed before 3 PM EST. Standard delivery is 3-5 business days.

Keep Your Cummins Engine Running Cool

OEM-quality water pump for Cummins 4B and 6B diesel engines. Prevents overheating and engine damage. Ships same-day.

ADD TO CART — $35.99
📞 Questions? (818) 261-3896