Dodge W150 Engine Coolant Bypass Hose Guide (1989-1993)
Everything you need to know about replacing the small but critical coolant bypass hose on your first-generation Dodge W150.
- The bypass hose is critical for preventing engine hot spots during warm-up.
- Failure is due to age; symptoms include leaks under the accessory bracket and overheating.
- Use a quality molded aftermarket hose from brands like Gates, Continental, Dayco, or ACDelco.
- Replacement is labor-intensive, making it a good time to service the entire cooling system.
Is Your W150's Bypass Hose Failing?
On a truck that's three decades old, rubber parts don't last forever. The bypass hose is constantly exposed to hot coolant and high pressure, leading to eventual failure. Because it's tucked under the accessory bracket, a small leak can go unnoticed until it becomes a big problem. Look for these signs:
- Mysterious Coolant Loss: You keep having to top off your coolant, but you can't find a major leak from the radiator or its main hoses.
- Engine Overheating: If the hose fails completely, you will lose coolant rapidly, causing the engine to overheat. This can lead to severe damage like a blown head gasket.
- Visible Leaks or Stains: Look for signs of coolant (typically green or orange) dripping from below the alternator and A/C compressor area. You may see crusty residue on the front of the engine or the timing cover.
- Damaged Hose: If you can see the hose, check for cracks, splits, or a soft, spongy, or swollen appearance. A hose that feels mushy to the touch is ready to fail.
Don't Ignore the Signs
A failing coolant bypass hose is not just an inconvenience; it's a direct threat to your engine. Continuing to drive with a significant coolant leak can lead to catastrophic engine failure.
Choosing the Right Aftermarket Hose
For the 1989-1993 W150, finding a new OEM Mopar bypass hose is highly unlikely. Thankfully, the aftermarket offers excellent, reliable options that meet or exceed original specifications. The most important factor is getting a molded hose designed for your truck's engine (3.9L V6, 5.2L V8, or 5.9L V8). Do not use a generic straight piece of hose, as it can kink and restrict flow.
Here's a breakdown of the available brands:
- Gates: Often considered the top choice in aftermarket hoses. Gates is known for its high-quality EPDM rubber that resists heat, ozone, and electrochemical degradation, which is the leading cause of hose failure from the inside out. Many professionals and DIYers trust Gates for fit and durability.
- Continental (ContiTech): Another premium German brand with a strong reputation for rubber products. Their hoses are engineered to OEM standards and are a reliable, high-quality choice.
- Dayco: A well-known and respected brand that offers a solid balance of quality and value. Some users note their hoses can feel slightly thicker, and they are a dependable option for any repair.
- ACDelco: While often associated with GM, ACDelco offers parts for many makes. Their hoses are generally considered professional-grade quality, and in many cases, they are manufactured by Gates.
Which Brand is Best?
Honestly, for your W150, you can't go wrong with any of these four brands. They are all reputable manufacturers. The biggest difference you might find is slight variations in price. Choose the one that is readily available and fits your budget; the quality will be sufficient to provide years of reliable service.
Estimated Costs
The cost to replace the bypass hose involves the part itself and the labor to install it. While the hose is inexpensive, the labor is more involved than a simple radiator hose swap.
| Item | Estimated Cost |
|---|---|
| New Aftermarket Bypass Hose | $13 - $27 |
| Shop Labor | $150 - $375 (1.5 - 2.5 hours) |
| Total Professional Replacement | $163 - $402 |
Frequently Asked Questions
Can I replace the bypass hose myself?
Yes, if you are an experienced DIY mechanic. The job requires draining the cooling system, removing the serpentine belt, and unbolting the alternator and A/C compressor to move them out of the way to access the accessory bracket. It is not a beginner-level task. If you are not comfortable with that level of disassembly, it is best to leave this job to a professional.
Do I need any special tools?
You will need a good socket set, a wrench for the belt tensioner, a drain pan for the coolant, and potentially hose clamp pliers. A fan clutch wrench may also be helpful. No highly specialized tools are required, but the job requires getting deep into the front of the engine.
Should I replace anything else at the same time?
Absolutely. Since you'll have the front of the engine disassembled, it is the perfect time to inspect and replace the serpentine belt, thermostat and gasket, water pump, and other coolant hoses like the upper and lower radiator hoses and heater hoses. This saves you from paying for the same labor twice in the near future.
Are there any recalls on this part?
No. Searches of the NHTSA database show no recalls or technical service bulletins (TSBs) for the engine coolant bypass hose on the 1989-1993 Dodge W150. Any failures are due to the age and normal wear of the part.
Technical Specifications
This is a molded EPDM rubber hose. Common aftermarket part numbers include Dayco 70637 and Gates 20693. Always verify fitment for your specific engine (3.9L, 5.2L, or 5.9L).
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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