Mishimoto MMHOSE-RADO-99BK Silicone Radiator Hose Kit for 1999–2006 Chevrolet Silverado 1500 V8

Four-Ply Reinforced Silicone

Each hose is manufactured from four layers of high-grade silicone with embedded heat-resistant fibers. This construction improves resistance to heat, pressure, cracking and age-related hardening.

Key benefits include:

• Four-ply silicone construction
• Heat-resistant embedded fibers
• Maximum temperature rating of approximately 330°F
• Increased pressure tolerance
• Factory-style molded routing
• Black finish
• Suitable for stock and modified trucks
• Mishimoto Lifetime Warranty

Silicone hoses do not create horsepower or lower the thermostat setting. They simply keep the coolant inside the system, which is admittedly a fairly useful feature.

Upgraded Lower-Hose Connection

The kit includes a preinstalled quick-disconnect connection on the lower radiator hose. Mishimoto also replaces the failure-prone plastic portion found in the original arrangement with a more durable connection design.

Inspect the retaining mechanism and seal before installation. The lower connector must seat completely and lock securely before the cooling system is refilled.

What’s Included?

The kit includes:

• One upper radiator hose
• One lower radiator hose
• Preinstalled lower-hose quick-disconnect fitting
• High-quality worm-gear clamps
• Required hose-installation hardware

It does not replace every heater, bypass, throttle-body or expansion-tank hose in the truck.

Signs Your Silverado Radiator Hoses Need Replacement

Replace the hoses when you notice:

• Cracks near a hose connection
• Soft, swollen or oil-contaminated sections
• Coolant residue around a clamp or fitting
• Leakage from the lower quick connector
• A hose collapsing during cooldown
• Abrasion against the fan shroud
• Coolant odor after driving
• Repeated coolant loss
• Engine overheating

Follow our guide on how to find a coolant leak if the source is difficult to locate. The lower connector and radiator tank connections deserve close inspection on an older GMT800 truck.

Installation Overview

Only open the cooling system after the engine has cooled completely.

A typical installation involves:

1. Confirm the engine size and truck configuration.
2. Photograph the factory hose routing.
3. Drain the coolant into a suitable container.
4. Remove the intake ducting if it blocks access.
5. Release the lower-hose quick connector.
6. Remove the original upper and lower hoses.
7. Inspect the radiator, thermostat housing and water-pump connections.
8. Clean every sealing surface.
9. Install the new hoses without twisting them.
10. Fully engage the lower quick connector.
11. Position each clamp behind the fitting bead.
12. Verify clearance from the fan, shroud, belts and pulleys.
13. Refill with compatible coolant.
14. Bleed trapped air from the system.
15. Bring the engine to operating temperature and inspect for leaks.
16. Recheck the coolant level after the engine cools.

Mishimoto commonly recommends approximately 22 in-lb for its worm-gear clamps, with a published working range around 18–27 in-lb. Confirm the instructions included with the kit and never exceed the stated limit.

Use our cooling-system flush guide if the existing coolant is contaminated or overdue for replacement.

Check the Rest of the GMT800 Cooling System

New hoses cannot compensate for another cooling-system fault. Inspect:

• Radiator tanks and core
• Water pump and gaskets
• Thermostat
• Mechanical fan clutch
• Fan blades and shroud
• Expansion tank
• Pressure cap
• Heater-hose connectors
• Drive belt and tensioner
• Coolant condition

Our complete cooling-system guide explains how these components work together.

For an overheating Silverado, use these resources:

• Why a vehicle overheats while driving
• Bad thermostat versus bad water pump
• Seven signs of a failing radiator
• How to install an LR4 water pump
• Car overheating while the heater blows cold
• Can radiator stop-leak cause damage?
• When should you stop driving?

Frequently Asked Questions

What years does MMHOSE-RADO-99BK fit?

It is designed for the 1999–2006 Chevrolet Silverado 1500 with a compatible V8 cooling system.

Which engines are compatible?

Published applications include the 4.8L and 5.3L V8, plus select 6.0L Silverado 1500, 1500 HD and SS configurations.

Does it fit the 4.3L V6?

No. This kit is intended for V8-equipped trucks.

Does it fit a Silverado 2500 HD?

Do not assume so. The kit is primarily cataloged for Silverado 1500 V8 applications. Silverado 2500 HD trucks can use different cooling packages, radiators and hose routing.

Does it fit a GMC Sierra?

The hose layout may cross over to certain GMT800 Sierra and SUV applications, but MMHOSE-RADO-99BK is officially marketed around the Chevrolet Silverado 1500. Verify by VIN, engine, radiator and original hose shape before purchasing for another GM model.

Does it fit a 2007 Silverado Classic?

Mishimoto’s published application ends with 2006. Verify directly with Mishimoto before ordering for a 2007 Classic.

Are upper and lower hoses included?

Yes. The kit includes both main radiator hoses.

Does the lower hose include its quick connector?

Yes. A quick-disconnect fitting is preinstalled on the lower hose.

Will it fit an aftermarket radiator?

It should fit direct-replacement radiators retaining factory connection locations and sizes. Measure custom or universal radiators before ordering.

Will new hoses fix an overheating Silverado?

Only when leaking, restricted or collapsing hoses caused the problem. A failed water pump, thermostat, fan clutch, radiator or head gasket requires separate diagnosis.

Product Specifications